Author Topic: Car stalls when warm  (Read 20926 times)

FDouma

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Car stalls when warm
« on: February 04, 2013, 19:48:22 »
Hi, I am restoring a 1963 220seb Coupe and have a stalling problem when the car reaching 80 degrees Celcius. While searching the internet for answers I found your website.

The car start quickly when cold (except for some spitback) but when idling it idels at 1100 Rpm. After app 10 minutes idling the RPM drops to 900 RPM and the car start to vibrate a bit, maybe because the feul is to lean.  When the temp gauge on the dashboard reaches 80 degrees Celcius  the car starts to stall. If you try to start engine again, it would not start. After cooling down the next morning, the engine start again.

While searching your website I found the Engine Starting Aid tour that was really helpfully.My car is fitted with the thermostatic system (version II) 
I understand that when starting the cold start valve (CSV) and the cold start soleniod (CSS) are activated. When the CSV is activated the valve opens in the manifold for exstra fuel at specified temputures. When the CSS is activated the rack in the injection pump move foward.

My question is, what happens at  80 degrees Celcius and why is the car stalling?

As I understand it the mechanical thermostat in the injection pump set out when getting warm to de-activate the CSS (mine is working) and the thermo time switch de-activated the CSV through a relay if coolant is above the cut off temputure. The time switch causes the CSV to be activated for 1 second even if coolant temputure is above the thermo time switch cutt of temputere.

I assume that the car is getting to much fuel when warm and it could be one of the following reasons:
1) The time switch is defect and activated for more then 1 second
2) the valve in the CSV is stuck, and does not close manually (The car is always in cold start mode)
3) the CSV relay is defect.

Regards

Frans




w113dude

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Re: Car stalls when warm
« Reply #1 on: February 04, 2013, 21:40:39 »
Hi Frans,

Go to search page look under WRD warm running device, It's the unit on the top of the injection pump, these are very common to get stuck & after the engine warms up it shuts down, there is plenty about on this forum.

ja17

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Re: Car stalls when warm
« Reply #2 on: February 05, 2013, 01:23:47 »
Hello Frans,

Check the basics first.


A lot of things can cause warm running and hot starting problems.

Your engine should be in tune. Check your compression, check the points, especially check  your idle timing and timing at 3,000 rpms.  A fresh set of NGK BP6ES spark plugs is an inexpensive but good investment since you will have the plugs out to check the compression.
 

You will need to make sure that the basics are in order first. Start with the Linkage Tour. Your engine linkages must be correct. Some of the dimensions will not be the same on your 220SE as our W113 cars but the section on the intake venturi switch is critical and a lot of the other information is relevant. The main fuel filter should be clean.  Your fuel pressure should be up to specs. Low fuel pressure could be caused by fuel line restrictions, plugged fuel screens in the electric fuel pump or fuel tank and defective check valve  on the fuel return line. Vapor locking fuel in the system can happen on hot engines if the fuel return line is restricted or the pump check is blocked. A lean running fuel mixture will also aggravate warm starting problems.  A split linkage test on your warm engine will confirm this.

Good that you checked and understand your starting aids. Un-hook the metal fuel line going to the cold starting valve on the intake manifold. Remove the metal fitting screwed into the intake. Check to make sure that the fine screen in this fitting  is not clogged. Also check the the slide valve moves freely.  Re-assemble.

Get familiar with the "split linkage test" and see if your mixture is really going lean after all systems are checked.

Split linkage co test
http://www.sl113.org/forums/index.php?topic=11162.0


Joe Alexander (ja17)
Blacklick, Ohio

Joe Alexander
Blacklick, Ohio
1969 Dark Olive 280SL
2002 ML55 AMG (tow vehicle)
2002 SLK32 AMG (350 hp)
1982 300TD Wagon turbo 4spd.
1963 404 Mercedes Unimog (Swedish Army)
1989 flu419 Mercedes Unimog (US Army)
1998 E430
1974 450SLC Rally
1965 220SE Finback

ja17

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Re: Car stalls when warm
« Reply #3 on: February 05, 2013, 05:25:04 »
Hello Frans,

You may also want to check the ignition spark plug wires and ends with an ohm meter if you have one. Don't make radical adjustments on your fuel injection until you make sure all the basics are in order.
Joe Alexander
Blacklick, Ohio
1969 Dark Olive 280SL
2002 ML55 AMG (tow vehicle)
2002 SLK32 AMG (350 hp)
1982 300TD Wagon turbo 4spd.
1963 404 Mercedes Unimog (Swedish Army)
1989 flu419 Mercedes Unimog (US Army)
1998 E430
1974 450SLC Rally
1965 220SE Finback