Starting problem when hot

[toneypenna]

Hello to everyone:
64 230 SL:

My new problem is car starts immediately when cold.  When it's warmed up or hot will not start.
Example, yesterday I started the car let it run for about 1/2 hour shut it off, won't re start.
I have read the technical manual, and many thread's regarding this.
I have tried 1/2 and full throttle with no positive result.
I have recently changed the TTS with a Bosch switch. It wasn't bad, at the time had difficulty starting when cold. I found a broken wire at TTS switch, repaired it and that solved cold start  problem. I only  changed the switch because one of the terminals was loose due to the bakelite or whatever that is on top of the switch was broken and the terminal was loose.
Yesterday, expecting that the engine would not start when hot, I rigged up a momentary switch to the CSV to see if that would help, but never got to try it. Before I tried to restart when it was hot I put a test light to the CSV expecting no power,  however I did have  power while cranking, from what I understand this is not correct, the CSV is only supposed to activate for cold starts. Activating the CSV at this time with the momentary switch would be redundant. Please correct me if I'm wrong.
Car has a new battery and even though it cranks well hot and cold, grasping at straws I put a charger on it thinking possibly if it would spin faster, it may start. No difference.
Although I don't think this problem is related, I have recently removed the head and had the valves and guides re done to solve a smoking problem

Any ideas of where I'm going wrong or additional tips on how to correct this.

Jim

[Pawel66]

The CSV is activated also when hot. For a brief moment, but it is. It is called a Cold Start Valve, but it also helps in hot start, the name is misleading.

My issue with hot start was clogged fuel filter causing fuel starvation. One of the experts here wrote once that hot start is the leanest condition the engine is ever in.

During restoration I had an intermediate in-line fuel filter installed between the tank and pump. I measured fuel flow at the end of return line, got poor result and that in-line filter was the first I looked at - it was full of debris. I replaced it, hot start came back. But it was just my case.

[ja17]

Jim,

First perform a fuel pressure and volume test. Next determine if your 230SL has version 2 or version 3 starting aids, (the 230SLs could have either). Version 2 uses a time switch along with the thermo time switch and one second relay. Version 3 uses no time switch. Report back on your findings.

[toneypenna]

Jim,

First perform a fuel pressure and volume test. Next determine if your 230SL has version 2 or version 3 starting aids, (the 230SLs could have either). Version 2 uses a time switch along with the thermo time switch and one second relay. Version 3 uses no time switch. Report back on your findings.

Interesting thought, I will check it out.

Thank you Jim

[toneypenna]

Jim,

First perform a fuel pressure and volume test. Next determine if your 230SL has version 2 or version 3 starting aids, (the 230SLs could have either). Version 2 uses a time switch along with the thermo time switch and one second relay. Version 3 uses no time switch. Report back on your findings.

Joe

I believe I have version 2, there are three relays on the inner drivers side fender. The first  (front) controls the CSV along with the TTS, the next I believe is windshield wiper relay, and then a round one that I believe control's the Injection pump solenoid. Does that denote Version 2?
I'll have to read up  in the technical manual on the fuel pressure and volume test, probably won't get to actually checking that out until Saturday. Will get back to you with results.

As always, thanks for your input.
Jim

[ctaylor738]

My 63 has four relays:  cold start valve (via TTS), injection pump solenoid, windshield wipers, and the round one second relay for the cold start valve.  The injection pump solenoid moves the rack to full rich when the starter is turning and in my experience is the most important in getting a 230 to start.  I have seen a couple of cars where this relay was removed, so you might poke around and see if there is an extra four-pin socket or some taped-off wires in the vicinity.

Good luck.  This can be a frustrating problem.

CT

[ja17]

Look for the Thermo Switch to identify Version 2. The thermo switch is a sensor which has only one wire going to it. Only version 2 will have the thermo switch. Both Version 2, and Version 3 have the Thermo Time Switch that have two wires going to them. Counting the relays will not identify the Version. Only the earliest 230 SL Pagodas had Version 2. Most 230SLs had Version 3.

[ctaylor738]

Hmm.  Sorry for hijacking the thread, but is this Version 0?

My '63, number 133 has two thermo switches.  One is the standard time switch with two wires.  The second (in the back) has a single wire.  Both provide ground to the cold start valve relay.  I believe the single wire switch was for engines up to #404.

Cheers,

CT

[BobH]

Hello to everyone:
64 230 SL:


...Before I tried to restart when it was hot I put a test light to the CSV expecting no power,  however I did have  power while cranking, from what I understand this is not correct, the CSV is only supposed to activate for cold starts. Activating the CSV at this time with the momentary switch would be redundant. Please correct me if I'm wrong...


Jim

As i understand it, on your car, the intake starting valve (CSV) receives a one second pulse from the time switch/time relay/one second timer, the round relay.  This happens regardless of engine temperature.  The contacts should provide a signal to the starting valve during cranking for one second only, as an aid to warm starting.  If you are receiving a signal there for more than one second, perhaps the thermal coil is open circuit and the contacts are remaining closed, if it is switching the intake starting valve for the full duration of your cranking, then the engine may well flood.  Perhaps unplug this timer relay and then see if it helps with your warm starting problem.  For cold starting the TTS provides the signal to the starting valve, so the one second relay doesn't play any part in cold starting

[rwmastel]

Look for the Thermo Switch to identify Version 2. The thermo switch is a sensor which has only one wire going to it. Only version 2 will have the thermo switch. Both Version 2, and Version 3 have the Thermo Time Switch that have two wires going to them. Counting the relays will not identify the Version. Only the earliest 230 SL Pagodas had Version 2. Most 230SLs had Version 3.

Correct me if I'm wrong, but I believe what you wrote could be rewritten:
Version 2 = single wire thermo switch
Version 3 = single wire thermo switch plus dual wire thermo time switch

[BobH]

Hmm.  Sorry for hijacking the thread, but is this Version 0?

My '63, number 133 has two thermo switches.  One is the standard time switch with two wires.  The second (in the back) has a single wire.  Both provide ground to the cold start valve relay.  I believe the single wire switch was for engines up to #404.

Cheers,

CT

Hello Chuck, from what i've read yours is version 11, i'm not too sure if there was a version 0 or 1?  Early cars up to late 63 had the thermo switch, a simple switch which opened the ground contact when the coolant temperature increased, and also the thermo time switch, which did the same, but also had a heater coil built in, which also opened the contact after a predetermined period of cranking.  i don't quite understand why both switches were fitted, it would be interesting to find out.  The one second timer relay was also fitted to assist in warm starting.  From what i understand the thermo switch was subsequently removed in late 63

[ja17]

Mercedes had five versions of starting aids for these mechanical fuel injected engines. Version I was an early system used on some other models produced before the W113 cars. Version 1 was never used on the Pagoda engines. Version 2 was an early version used on the next  models including the earliest 230SLs. This version 2 can be identified as having a thermo-switch). Don't confuse this with the round "time switch" which is simply a 1 second relay. By far the most common version used on the pagoda engines was version 4 (late 1965 to sometime in 1970) . You cannot gather all this information in one BBB. You would need to study both. The best source of information is our technical manual which has graphs, diagrams and pictures. Much of the information is original from our group and cannot be found anywhere else. In addition Version 2 can be modified to perform the same as version 3. Also Mercedes produced a factory modification kit for version 4 to improve starting if needed. It can be complex to understand all the versions. My personal notes on "starting aids" is a loose leaf binder with about 200 pages of information!

[rwmastel]

My personal notes on "starting aids" is a loose leaf binder with about 200 pages of information!

I'll be over this weekend with a mobile photo copier!   

[mauro12]

Could be also leaking delivery valves on the injection pump . They don’t keep enough pressure and fuel is boiling inside the tubes . You need to crank several times in order to build up pressure in the lines .
Correct me if I’m wrong .

[rwmastel]

Yes, that's possible.  There are a lot of things possible.  We just need to suggest good tests to narrow down and eventually identify the problem.

[toneypenna]

Look for the Thermo Switch to identify Version 2. The thermo switch is a sensor which has only one wire going to it. Only version 2 will have the thermo switch. Both Version 2, and Version 3 have the Thermo Time Switch that have two wires going to them. Counting the relays will not identify the Version. Only the earliest 230 SL Pagodas had Version 2. Most 230SLs had Version 3.

I stand corrected, which i'm getting real used to with this car. It appears to have version three, just the TTS with two wires, I looked all over the block and could not find another one with one wire.
I did find this (picture attached) it's on the inside of the right front fender. Looked in the tech manual, couldn't find anything there either, maybe I'm using it wrong or didn't look in the right place.
Hoping to get to the fuel tests on Saturday, and will report back.

As always, Thank You

Jim

[ja17]

Jim, that is the voltage regulator.

[BobH]

As i understand it, on your car, the intake starting valve (CSV) receives a one second pulse from the time switch/time relay/one second timer, the round relay.  This happens regardless of engine temperature.  The contacts should provide a signal to the starting valve during cranking for one second only, as an aid to warm starting.  If you are receiving a signal there for more than one second, perhaps the thermal coil is open circuit and the contacts are remaining closed, if it is switching the intake starting valve for the full duration of your cranking, then the engine may well flood.  Perhaps unplug this timer relay and then see if it helps with your warm starting problem.  For cold starting the TTS provides the signal to the starting valve, so the one second relay doesn't play any part in cold starting

If you're getting power at the intake starting valve (CSV) all the time when you're cranking, that's not correct, you'll also be getting power at the injection pump solenoid, (if you have one) so will definitely flood the engine

There will be a problem with the starting aid system, the relay or the time switch, pictures of both are on here

https://www.sl113.org/forums/index.php?topic=36601.0

Easy to investigate these first, either unplug the timer and see what happens, or disconnect the wire at the CSV and pump solenoid (if you have one, depending on your pump type) and see if that improves the warm start

[ja17]

Chuck, you do not have two "thermo switches" the one with two wires is a "thermo time switch".  Rodd, Version 2 has both, a single wire "themo switch" and a two wire "thermo time switch". Version 3,4,5 do not have a single wire time switch. You can look at my graphs in "The Starting Aid Tour" and see what device is activated, how long it is activated, and at what temperatures it is activated according to the Version. I made and posted charts for versions 3,4 & 5.

[toneypenna]

Jim,

First perform a fuel pressure and volume test. Next determine if your 230SL has version 2 or version 3 starting aids, (the 230SLs could have either). Version 2 uses a time switch along with the thermo time switch and one second relay. Version 3 uses no time switch. Report back on your findings.

Joe

Finally got to do the fuel pressure test  yesterday.
Looked all over couldn't find a TS so I would think this is version 3.

My findings, fuel pressure 19lbs. Volume:  allthoug I didnt actually measure the1 litre in 15 seconds flow rate, there is a good flow and from experience I believe it would qualify for those specs. Additionally, I have timing set about 32/35 any further and it wants to kick back on the starter.
The following is my experience with it yesterday: Starts cold no problem, after reaching operating temp, it started difficult once with promting by holdoing accelerator open. After that wouldn't  start at all, just cranks like ther is no spark, however when I check for spark there is.  Put a test light on the cold start valve and it lit for a second or two during cranking, from what I've read this is correct. Hooked up momentary switch to the TTS held it on during cranking, light stayed on, however had no effect on it starting. Left it and haven't gone back to it, but when I do it will probably start right up.

I'm lost with this, any help you can give would be greatly appreciated.

Jim

[ja17]

Your making progress. Next check the starting solenoid on the injection pump. It should activate for at least one second on any cold and hot starts, with version 3.

[toneypenna]

Your making progress. Next check the starting solenoid on the injection pump. It should activate for at least one second on any cold and hot starts, with version 3.

Joe
It appears this car wants to do me in. Pulled the coil wire so it wouldn't start while testing the injection pump solenoid. put test light on it and it lit for about 3 seconds during cranking. While I was at it I thought I would test the CSV again, test light also lit for a bout 3 ,seconds. I  plugged the coil wire back in turned the engine over and it wanted to start on the initial revolution but didn't. Sounded like a carburated engine would if you tried to start it with out stepping on the accelerator. ( Initially fire off but immediately stall) Tried again this time holding the throttle open various degrees, no luck. Left it sit for about 20 min same result, checked for spark again, it has spark.
Naturally never got a chance to test the injection pump solenoid when at operating temperature.
Had to leave, going back later will try to start it then.

Jim

[alchemist]

You may search "Mercedes Hot Vapor Lock" which was and still is a notorious problem in the 1970's and for a variety of Mercedes models such as 450SL. It has to do with bubbles in the gas lines when the car is hot. Good Luck.

[toneypenna]

Joe

Tried again to start it, no go. So now it looks like I have to fix a cold start problem before we can adress the hot start problem. I believe I'm  getting a gas odor after trying to start. Also in snooping around looking for something I noticed that  the CSV has a crack in it,  the valve doesn't look that old but looks like someone previously tried to  repair it as I see what appears to be glue on it. The crack is in the housing only almost like the ear was broken and they glued it back on. I'm attaching a picture. Can't see how this would cause my problem but stranger things have happened.

Thanks,

Jim

[alchemist]

Smelling gas is an indication of flooding. You may check the spark plug after cranking and smell it. If you find sign of flooding, then you need to adjust the knob at the back of the injection pump. Turn it counter clockwise few notches when the engine is not running.

[rwmastel]

Tried again this time holding the throttle open various degrees, no luck.

Alchemist,
This is probably the source of the fuel smell, holding the throttle down while cranking & not starting.

[toneypenna]

You may search "Mercedes Hot Vapor Lock" which was and still is a notorious problem in the 1970's and for a variety of Mercedes models such as 450SL. It has to do with bubbles in the gas lines when the car is hot. Good Luck.

Thank you for your input. I'm surprised to hear of a vapor lock problem on the later Mercedes that I believe were also fuel injected. The way I or we used to correct vapor lock problems on older carbureted domestic cars was to install a three nipple fuel filter ( I think were used in Jeeps) between the mechanical pump and the carburetor and run the third nipple back to the vent line on the tank, in essence a return line.
Since fuel injected cars run at a higher pump pressure and also have a return line, I didn't think vapor lock could be a problem, but I suppose anything is possible.
Thanks,

Jim

[toneypenna]

Smelling gas is an indication of flooding. You may check the spark plug after cranking and smell it. If you find sign of flooding, then you need to adjust the knob at the back of the injection pump. Turn it counter clockwise few notches when the engine is not running.

Good thought, I will check it out. Never had this problem before, wasn't running rich when it last started, but who knows.

Thanks,

Jim

[ja17]

Vapor lock on these cars is usually due to fuel not circulating back to the fuel tank. The fuel flow is a continuous loop on these engines, which depends on the cool fuel circulating from the tank to keep all the components (IP, fuel lines and gasoline) cool. When circulation is poor, the heat from the engine warms the entire system and can cause the fuel to vaporize. Difficult hard starting can result. The most common problems of poor circulation are; low fuel pressure, low fuel volume (flow rate), a plugged fuel return line, plugged fuel filter, plugged fuel pump screen, plugged tank screen, debris in fuel tank or a stuck or improper fuel return check valve at the injection pump. Modern alcohol fuels can aggravate the problem since they have a lower boiling point than traditional gasoline. 

[toneypenna]

Vapor lock on these cars is usually due to fuel not circulating back to the fuel tank. The fuel flow is a continuous loop on these engines, which depends on the cool fuel circulating from the tank to keep all the components (IP, fuel lines and gasoline) cool. When circulation is poor, the heat from the engine warms the entire system and can cause the fuel to vaporize. Difficult hard starting can result. The most common problems of poor circulation are; low fuel pressure, low fuel volume (flow rate), a plugged fuel return line, plugged fuel filter, plugged fuel pump screen, plugged tank screen, debris in fuel tank or a stuck or improper fuel return check valve at the injection pump. Modern alcohol fuels can aggravate the problem since they have a lower boiling point than traditional gasoline.

Joe,

Thanks again for the enlightenment,
I know I have good fuel pressure and volume but before I can go any further on the hot start problem I have to get it to start when cold. Have tried almost every time I walk by it, just won't start. I'm hoping for some time tomorrow to try to get to the bottom of it. The only thing I did before the cold start problem developed was reset the timing so back to basics  first I'll try retarding it a bit and see if that helps. Still don't know if the repaired CSV would have any effect on either or both of the problems, I gueess I can always take it off and inspect it further.
Hope i'm not wearing out my welcome with you. I'll let you know what I find.

Again, Many Thanks.

Jim

[ja17]

If it has fuel, spark on time, and compression it will start. First try giving it a squirt of starter fluid and see if it kicks. If it does your problem is no or not enough
fuel.

[toneypenna]

If it has fuel, spark on time, and compression it will start. First try giving it a squirt of starter fluid and see if it kicks. If it does your problem is no or not enough
fuel.

Joe

Got a chance to spend some time on the car late today. To recap, we had power to both the CSV and pump solenoid on cranking for about 3 seconds when cold and 19 PSI on the fuel pressure taken at the return line with adequate flow.
Solved the cold start problem by retarding the spark probably 3 to 5 degrees which tells me I had the timing  to far advanced. (thought I had it at 35 at 3000 RPM.)
Let the car get to operating temp, shut it down, tested the CSV and Pump solenoid again while cranking when hot and got the same results, both lit the test light for about the same  3 or 4 seconds. Also checked fuel pressure again when warm and I'm assuming it's the same. For some reason my snap on gauge stopped working, so I used another one I had that only went to 10 PSI max , it pinned the gauge and bounced like it wanted to go further.
Tried to re start it a couple of time when hot and it would finally start on the second or third revolution only if I held the throttle open about 1/2 way. I let it run and checked the timing and it's now set at 38  so I left that alone. Let it run, shut it down numerous times and it restarted with difficulty with the throttle held open about 1/2 way.
Other than that it idles happy at about 750 / 800 rpm. I think I'm making some progress but I keep thinking that there is something simple that I'm not seeing that causes this hard hot start.
Any suggestions or corrections as to how to make it start easier when at operating temp would be greatly appreciated..

Jim

[ja17]

Try disconnecting the two starting device one at a time, during warm starts, to see if it helps. You could be flooding when warm.

[rwmastel]

Following along out of general interest...

Why would pressing the gas pedal 1/2 way when cranking help start a car already in a flooding or fuel rich configuration?  The open air flap on the intake is needed?

[alchemist]

Thank you for your input. I'm surprised to hear of a vapor lock problem on the later Mercedes that I believe were also fuel injected. The way I or we used to correct vapor lock problems on older carbureted domestic cars was to install a three nipple fuel filter ( I think were used in Jeeps) between the mechanical pump and the carburetor and run the third nipple back to the vent line on the tank, in essence a return line.
Since fuel injected cars run at a higher pump pressure and also have a return line, I didn't think vapor lock could be a problem, but I suppose anything is possible.
Thanks,

Jim
Jim: I am referencing fuel injected Mercedes in the 1970's and 1980's. I mentioned 450SL which is fuel injected with Bosch injection system with no carburetor. The vapor lock problem still exist in these fuel injected Mercedes.

[Pinder]

Im also following along.  for what is causing this. I would guess the warm up device on the IP.  when cold it has the right fuel mixture  but then when all warmed up its allowing too much fuel causing rich state.

[ja17]

Rodd,
The mixture equation is not proportional since the flyweights in the injection pump spin very slow during cranking. It seems to me that the more throttle you give, the leaner the air to fuel mixture becomes. Injected fuel increases with rack movement (throttle linkage position, engine rpms and engine temperature). Since rpms are low during cranking, additional fuel from the rpms is virtually non existent. With more throttle, a higher percentage of air would be introduced along with a smaller ratio of fuel. Experimenting with throttle position can help determine starting issues, (both lean and rich). Don't depend on smell. Faulty ignition or fouled plugs will release unburned fuel. Low ignition voltage, especially with the low power coils on the early ignitions, can contribute to poor starting also.

[toneypenna]

Try disconnecting the two starting device one at a time, during warm starts, to see if it helps. You could be flooding when warm.

Joe
Looks like you were right again. What I did on Saturday: Started it cold no problem, let it get to operating temperature, shut it down, tried starting, wouldn't start. Disconnected CSV at relay, still wouldn't start, then disconnected IPS at relay and it started running rough at first. I'm assuming due to  burning off excess fuel. Shut it down and restarted it 6 or 8 times, starting immediately on the first crank the way it should, let it sit about two hours, as I was leaving I tried to start it, wouldn't start while CSV and IPS were still still disconnected.

Went back on Sunday, Wouldn't start, connected the CSV it started with no problem, then connected tie IPS while running and again let it get to operating temp then shut it down.
Tried starting with the two starting devices connected, wouldn't start. This time I disconnected the IPS first and it started, but  with difficulty, shut it down and disconnected the CSV and it started  with no problem like it should.

Note I did disconnect both starting devices each time, one at a time,  but in different sequence.

As you initially suggested, it looks like I have a fuel problem when at operating temp. What would be my next step, is there a remedy for this?

As always, thank you for your time and knowledge.

Jim

[toneypenna]

Thank you for your input. I'm surprised to hear of a vapor lock problem on the later Mercedes that I believe were also fuel injected. The way I or we used to correct vapor lock problems on older carbureted domestic cars was to install a three nipple fuel filter ( I think were used in Jeeps) between the mechanical pump and the carburetor and run the third nipple back to the vent line on the tank, in essence a return line.
Since fuel injected cars run at a higher pump pressure and also have a return line, I didn't think vapor lock could be a problem, but I suppose anything is possible.
Thanks,

Jim
Jim: I am referencing fuel injected Mercedes in the 1970's and 1980's. I mentioned 450SL which is fuel injected with Bosch injection system with no carburetor. The vapor lock problem still exist in these fuel injected Mercedes.

Agreed, I was not try to contradict you, just wasn't aware a fuel injected engine could suffer from vapor lock. I stand corrected. I realize carburated and fuel injection systems are completely different ballgames. My thinking was to correct vapor lock in a carburated engine we added a return line to the tank and it usually solved the problem. Sorry if there was a misunderstanding.

Jim

[ja17]

Jim, do you have a modern gear reduction starter on your car? You'll never guess how this may be richening your starts, if you do.

[toneypenna]

Jim, do you have a modern gear reduction starter on your car? You'll never guess how this may be richening your starts, if you do.

Not as far as I know, sounds and looks like a normal starter, however I did convert to an electronic 123 distributor a while ago. At the time I searched the forum and the consensus for this was favorable upgrade.
I don't want to mess with the fuel adjustment on the injection pump unless I have some direction so I don't make matters worse. Is this a possibility or is there something else I can try?

Jim

[ja17]

Have you tried using a lot more pedal during hot starts?

[toneypenna]

Have you tried using a lot more pedal during hot starts?

Joe

Been through the more and less pedal when hot more than a few times, sometimes it does and sometimes doesn't start no matter what amount I depress the pedal. The few times it did start it was with great difficulty. Not a reliable way to restart when at operating temperature. The only way it has started as it should at operating temp is by disconnecting the CSV and IPS. as you suggested, then it starts no problem. Question is how to correct this? It's evidently an excess fuel problem, can this be adjusted in some way? I would think that leaning out the fuel mixture (which I don't have any experience with) may have an adverse effect on the overall way the engine runs. In other words, setting the fuel mixture for hot starting may be to lean for cold start and overall running of the engine. I have searched the tech manual and forum on this type of problem but have not come up with a definitive answer. Possibly I'm not looking in the right places.
My other thought was to rig up some sort of switch to disable the CSV and IPS to facilitate starting when hot. Just a thought, I don't even know if that's possible. I really wouldn't want to go that route unless it was absolutely necessary for fear of causing another problem. I would much rather have the car functioning as it should.

Many Thanks,

Jim

[ja17]

If yours is actually version 3, then the two starting aids are wired together. Reducing fuel supply to the IP solenoid would result in a reduction of fuel at the CSV. Do you know how to do the "split linkage test"?

[ctaylor738]

The only way to really test the cold start valve is to remove it, turn it around, reconnect the fuel line, and the wiring (jumpers are OK). Put the valve in a plastic bag and crank the starter.  To be effective, the valve has to spray, not pee or dribble.

To test the solenoid, remove the cap on the fitting at top front of the pump and thread a M5x40 bolt or screw into the end of the rack.  Crank the starter and see it the screw moves out.

I feel your frustration.  My 230sl is a real pain to start hot as well.  Even if it is shut off for less than a minute, it takes a lot of cranking with the accelerator on the floor to get it going.  When it starts to fire, it's one cylinder at a time.  But no stink out the exhaust.  All of the "starting aids" have been tested and are working.  It hasn't left me stranded yet, but there have been a couple of close calls.

Cheers,

CT

[toneypenna]

The only way to really test the cold start valve is to remove it, turn it around, reconnect the fuel line, and the wiring (jumpers are OK). Put the valve in a plastic bag and crank the starter.  To be effective, the valve has to spray, not pee or dribble.


CT
I believe what you’re telling me is to test if these devices are working mechanically. Testing with a test light only tests if they are working electrically.
Correct? I will try this, however I believe they are working because of the following.9
What’s confounding me is when it doesn’t start hot, if I disconnect the CSV and the IPS at their respective relays, it starts immediately as it should.
Thank you for your input.
Jim

To test the solenoid, remove the cap on the fitting at top front of the pump and thread a M5x40 bolt or screw into the end of the rack.  Crank the starter and see it the screw moves out.

I feel your frustration.  My 230sl is a real pain to start hot as well.  Even if it is shut off for less than a minute, it takes a lot of cranking with the accelerator on the floor to get it going.  When it starts to fire, it's one cylinder at a time.  But no stink out the exhaust.  All of the "starting aids" have been tested and are working.  It hasn't left me stranded yet, but there have been a couple of close calls.

Cheers,

CT

[toneypenna]

If yours is actually version 3, then the two starting aids are wired

If yours is actually version 3, then the two starting aids are wired together. Reducing fuel supply to the IP solenoid would result in a reduction of fuel at the CSV. Do you know how to do the "split linkage test"?
[/quote

No I don’t, is it in the technical manual?
I’ll search for it unless it’s a simple thing and you wouldn’t mind explaining it.

Thanks
Jim

[Lorsar]

https://www.sl113.org/wiki/Restricted/Linkage-tour

[ctaylor738]

Jim -

Yes, that's exactly what I'm saying.  Testing the electricals will not tell you that the cold start valve is spraying or that the rack is actually moving.

Earlier, I had cold start problems as well.  After verifying the electricals and testing the as described, I found I had a peeing cold start valve.  I installed an expensive new valve that sprayed perfectly.  Still no start.  A new battery got it going after long cranks.  In desperation, I disconnected the cold start valve and was astounded when the car started on the turn of the key.  I have left it that way since.

I also have a manual switch for the cold start valve, but it makes no difference on hot starts.

I call it COPS - Cranky Old Pump Syndrome.

My theory is that the Warm Running Device alone gets the engine going when cold.  Hot, the injection pump is not developing enough pressure to open the injectors.

I have a new starter that I am going to install to see if higher cranking speed will help the hot start.

Cheers,

CT

[toneypenna]

https://www.sl113.org/wiki/Restricted/Linkage-tour

Thank you, I have already done all those adjustments and installed all new socket joints to alleiate the play in the linkage.

Jim

[toneypenna]

If yours is actually version 3, then the two starting aids are wired together. Reducing fuel supply to the IP solenoid would result in a reduction of fuel at the CSV. Do you know how to do the "split linkage test"?

Joe

Is the split linkage test the same as the linkage and idle adjustments listed in the tech manual? If yes I previously did that along with replacing the ball sockets to alleviate the play in the linkage.

Jim

[ja17]

Don't confuse the split linkage "test" with The Linkage "Tour". The split linkage test is a way to perform a basic fuel injection mixture test.

[toneypenna]

Jim -

Yes, that's exactly what I'm saying.  Testing the electricals will not tell you that the cold start valve is spraying or that the rack is actually moving.

Earlier, I had cold start problems as well.  After verifying the electricals and testing the as described, I found I had a peeing cold start valve.  I installed an expensive new valve that sprayed perfectly.  Still no start.  A new battery got it going after long cranks.  In desperation, I disconnected the cold start valve and was astounded when the car started on the turn of the key.  I have left it that way since.

Ct,

Thank you for your input, My problem is it starts when cold but wont start hot. If I disonect the CSV and the IPS at their respective relays it starts right up when hot, but wont start with them disconnected when cold. I have to do some research on this, but I'm thinking of wireing a switch that will disengage both the CSV and the IPS when hot to assist in starting. Your thoughts?

Jim

I also have a manual switch for the cold start valve, but it makes no difference on hot starts.

I call it COPS - Cranky Old Pump Syndrome.

My theory is that the Warm Running Device alone gets the engine going when cold.  Hot, the injection pump is not developing enough pressure to open the injectors.

I have a new starter that I am going to install to see if higher cranking speed will help the hot start.

Cheers,

CT

[toneypenna]

Don't confuse the split linkage "test" with The Linkage "Tour". The split linkage test is a way to perform a basic fuel injection mixture test.

Joe
Thanks, I’ll look further in the tech manual for the split linkage test.
Jim

[ja17]

Remember fuel returning to the fuel tank is critical for hot starts. The fuel return line of the injection pump is where the check valve or special fitting is located.  It most allow fuel to return to the tank. You can remove the gas cap and blow some air in the return line up front and listen for air bubbling in the gas tank.

[toneypenna]

Remember fuel returning to the fuel tank is critical for hot starts. The fuel return line of the injection pump is where the check valve or special fitting is located.  It most allow fuel to return to the tank. You can remove the gas cap and blow some air in the return line up front and listen for air bubbling in the gas tank.

Joe

Haven't had any luck finding  the split linkage test in the tech manual, can you point me in the right direction?
It seems not only can't I correct this starting ptoblem, I can't even locate  testing procedures in the manual.
I suppose this frustration shall pass.

Jim

.

[rwmastel]

I believe a link to the video in the below thread is in that same part of the Tech Manual.  It's good to see video & hear sound as it is being explained.  A good separate text write up is also helpful, but I'm also having difficulty finding it.  I know it exists.

https://www.sl113.org/forums/index.php?topic=29836

[toneypenna]

I believe a link to the video in the below thread is in that same part of the Tech Manual.  It's good to see video & hear sound as it is being explained.  A good separate text write up is also helpful, but I'm also having difficulty finding it.  I know it exists.

https://www.sl113.org/forums/index.php?topic=29836

Rodd,

Thank you so much for that U Tube link, After some of these tests are explained to me it"s basic automotive stuff that I can't come up with. That's what makes this forum an invaluable source of knowledge. I'll be doing that test today.

Again thank you,

Jim

[ctaylor738]

Jim,

I believe you can go to full manual control of the starting aids as follows:

- disconnect the pink wire from the thermo-time switch
- extend the wire to reach where you want to mount the switch
- connect the wire to one side of a "momentary" switch of your choice
- connect the other side of the switch to ground
- mount the switch

I recommend you mount the switch to the left of the steering column so you can operate the ignition switch with your right hand and the new switch with your left.

Cheers,

CT

[toneypenna]

Jim,

I believe you can go to full manual control of the starting aids as follows:

- disconnect the pink wire from the thermo-time switch
- extend the wire to reach where you want to mount the switch
- connect the wire to one side of a "momentary" switch of your choice
- connect the other side of the switch to ground
- mount the switch

CT

Thank you for this, it's what I may have to do. Something I don't understand maybe you can enlighten me. If I disonnect the pink wire from the TTS, doesnt that in itself disable the TTS and by running the wire to a monentary switch, wouldn't that enable the TTS? Does this also effect the IPS. My object is to disable both these devices when hot so engins starts.

JIm

I recommend you mount the switch to the left of the steering column so you can operate the ignition switch with your right hand and the new switch with your left.

Cheers,

CT

[toneypenna]

Joe

As you suggested I blew air into the return line, heard air bubbles in the fuel tank, allthough initially there seemed to be some hesitation for the air to get through. The second time it was immediate.
Also did the split linkage test as you suggested. Engine sped up when I introduced additional air at the throttle body. Tells me it's running rich. Shut the engine down,  Went to the click adjustment knob on the back of the pump and tried to lean it out by turning counter clockwise. It seems I have another problem here. Push the knob in and turn, doesn't engage, cant get it to give any definite clicks. Something is not right. Question, If I were to remove the large hex nut is it possible to inspect whats going on in there? Is this a simple thing or are there a lot of parts that I'm going to have to deal with? Would like to know what I'm getting into before I cause myself another problem.

Don't confuse the split linkage "test" with The Linkage "Tour". The split linkage test is a way to perform a basic fuel injection mixture test.

  I checked in the tech manual and couldn't info on this.

Thank You

Jim

[Pinder]

Jim

 when I first tried to adjust the Injection pump using the knob by pushing it in and turning, it was very difficult to do as it is very stiff to turn.  push it all the way in and move it left and right until you feel it slotting in. at that point it will feel like it went in a bit furth and when you try to move it left or right it wont easily move, then apply more pressure and it will move like a 1/4 turn.

Here is a great video that my help you to get a good understanding how the fuel / air mixture  changes or should change as the car warms up.

https://www.youtube.com/watch?v=F6sxlOFmoYw&t=1569s

Regards

 Pinder

[ctaylor738]

Jim,

As I read the late 230sl wiring diagram, the thermo-time switch provides ground to the relays that control the pump solenoid and the cold start valve.  You would replacing that function with your new momentary switch.

CT

[toneypenna]

Jim

 when I first tried to adjust the Injection pump using the knob by pushing it in and turning, it was very difficult to do as it is very stiff to turn.  push it all the way in and move it left and right until you feel it slotting in. at that point it will feel like it went in a bit furth and when you try to move it left or right it wont easily move, then apply more pressure and it will move like a 1/4 turn.

Here is a great video that my help you to get a good understanding how the fuel / air mixture  changes or should change as the car warms up.p

Pinder,

Thanks for your input, great video.

My problem is the knob turns freely, no resistance, but when you push it in and turn it to engage in the slot  it doesn't, feels like isn't doing anything. If it were to engage it would go in a little farther, it doesn't. That's whats making me think something is wrong inside. I'm picturing a pin on the inside end of the knob that when you push it in it engages with a slot on a shaft. Without looking in there, it feels like the pin isn't there or os broken.

Jim
https://www.youtube.com/watch?v=F6sxlOFmoYw&t=1569s

Regards

 Pinder

[toneypenna]

Jim,

As I read the late 230sl wiring diagram, the thermo-time switch provides ground to the relays that control the pump solenoid and the cold start valve.  You would replacing that function with your new momentary switch.

CT

CT

I should have thought about this like a rational adult before I answered your post. With what you are suggesting, I would be disabling both devices, the CSV and the IPS. Then the momentary switch would engage both when needed. This would help my problem, the two devices would be dormant during a hot start and could be engaged with the momentary switch when needed for a cold start.
I was not questioning you, just didn't full understand it until I gave some further thought.

Thank You for your input.

Jim

[rwmastel]

Tony,

Please don't reply within the quote.  Put your text below it.

"I'm picturing a pin on the inside end of the knob that when you push it in it engages with a slot on a shaft. Without looking in there, it feels like the pin isn't there or os broken."

Yes, you can think of it like you're operating a spring loaded flat head screw driver.
- push in against spring resistance
- turn to find the slot, seat the driver into the slot
- turn with some effort

[Pawel66]

https://www.sl113.org/wiki/Fuel/Injection#Pump

On the picture in our Technical Manual, the hex head screw in the middle, which is the idle (up to ca 1500rev/min) adjustment screw, is rotating between the two "leaf" springs on top and at the bottom of the screw head. This is where the clicks come from and it is also the source of resistance when you turn this screw.

I do not have a picture of it (I am sure it is there somewhere on the Forum), but the screw with the knurled knob sticking out of the FIP, has a wide screwdriver-like tip. You need to push it in, turn slowly so that tip gets into slot in the hex head of the screw. Then you will feel much more resistance while attempting to turn it - because of the two leaf springs. But if attempt to turn the adjustment screw requires a lot of force - perhaps something got stuck there...

[toneypenna]

Tony,

Please don't reply within the quote.  Put your text below it.

"I'm picturing a pin on the inside end of the knob that when you push it in it engages with a slot on a shaft. Without looking in there, it feels like the pin isn't there or os broken."

Yes, you can think of it like you're operating a spring loaded flat head screw driver.
- push in against spring resistance
- turn to find the slot, seat the driver into the slot
- turn with some effort

Rodd,

Sorry about that, didn't intentionally reply within the quote,  didn't notice until it was posted and then didn't know how to fix it. I'll watch more carefully in the future.

Haven't had time to address my problems with  the car, Holiday obligations took precedent, will get back to it and post my findings.

Thanks,

Jim

[ja17]

Make sure the engine is warmed up before adjusting the IP. Cold running adjustments are different. Remember the thumb screw on the back of the IP just regulates mixture up to around 1500 rpms. for a warm engine. Turning the thumb screw clockwise (sitting in the drivers seat looking forward), RICHENS the mixture in the up to 1500 rpm range.

[toneypenna]

Make sure the engine is warmed up before adjusting the IP. Cold running adjustments are different. Remember the thumb screw on the back of the IP just regulates mixture up to around 1500 rpms. for a warm engine. Turning the thumb screw clockwise (sitting in the drivers seat looking forward), RICHENS the mixture in the up to 1500 rpm range.

Joe

Thanks for the tip. With the Holidays and playing catch up with the lost time, I haven't had much time to delve into my problems with the car. I should be getting back to it this week. Will post my findings

Jim

[toneypenna]

Been away for a while , and thought I would close out this thread by letting everyone know thanks to all of you, my problems have been resolved. Regarding the click adjustment that I couldn't turn, I took off the cover, put a screwdriver on it and turned it one click back and forth, evidently it was stuck. Put the cover back on and using the split linkage test, I was able to adjust and get an acceptable idle.
Regarding the hot start problem, I disconnected the ground side of TTS switch and wired a momentary switch to control it manually as suggested and that solved the hot start problem. Another problem I had that i never posted was an intermittent brake hang up. Booster and Master had been replaced for vacuum and fluid leaking problems. Found the RF Caliper hanging up, replaced that, but still had the same problem.Finally found the brake kinkage pivot below the booster was sticking. Took it all apart cleaned and lubricated that and problem was solved.
Without going into a long story as to why, I'm going to be sending this car to my Nephew in California, If anyone can recommend a reputable shop to service / repair this car when needed, It would be greatly appreciated. This 64 230 SL will be living in the Malibu,Thousand Oaks, Agoura Hills,Calabasas area.
Again, thank you all for sharing your knowledge and expertise.
 I will also be posting my request for a shop recommendation on the discussion board

[rwmastel]

Regarding the hot start problem, I disconnected the ground side of TTS switch and wired a momentary switch to control it manually as suggested and that solved the hot start problem.

Well, not solved I would say.  It's a work around.  Maybe getting the TTS system replaced or repaired would be a good first task for your nephew.

[ctaylor738]

Jim,

Way to hang in there!

CT

[toneypenna]

Well, not solved I would say.  It's a work around.  Maybe getting the TTS system replaced or repaired would be a good first task for your nephew.

Yes, I agree, I would have liked to have had it working properly. I changed the TTS twice, first one was defective. My problem as outlined in my posts was car started fine on initial start when cold, would not start when at operating temperature unless I disconnected the CSV and IPS relays, then it started fine. I searched the tech manual and the forum, plus the many  reply's to my posts by members and this was the only fix or work around I could come up with. Thank you for your input.

Jim

[stickandrudderman]

Something often overlooked is whether the cold start device is functioning properly; that is does it add air for fast idle when cold and does that air reduce as the engine warms up.
If it's stuck you can be chasing starting problems until the cows come home.

[toneypenna]

Something often overlooked is whether the cold start device is functioning properly; that is does it add air for fast idle when cold and does that air reduce as the engine warms up.
If it's stuck you can be chasing starting problems until the cows come home.

I did test the CSV back when I was having the problem. I removed it, turned it around , hooked up the fuel line, put it in a plastic bag and it sprayed fuel as it should. However it is moot at this point as I just sent the car to my nephew in California with a momentary switch hooked up to enable the CSV that apears to be only needed during cold starts.. Thank you for your input.
I'm looking for a reputable shop in the Malibu, Thousand Oaks, Agoura Hills, Calabasas area to service the car when needed.
Any recommendations will be greatly appreciated.

[stickandrudderman]

I'm talking about the cold start mechanism on the pump, not the cold start spray valve on the inlet manifold.

[toneypenna]

I'm talking about the cold start mechanism on the pump, not the cold start spray valve on the inlet manifold.

Thanks for clarifying that.

Jim