Author Topic: engine breakdown ?  (Read 2015 times)

yves

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engine breakdown ?
« on: September 21, 2019, 20:12:45 »
While i was refurbishing my steering box which had leaks , i have polished the throttle links . When i tried to start after all these job done the engine goes very hight in Revs  and then cut….. i must have done a mistake with the throttle linkage but i Don't know what hapened ?
On the photos below  : the two linkage rods polished : 1


I wonder if there is something wrong about the air trap coming from the air filterbox (2)  , because i have also unsettled the trap mecanism and fitted after polishing but every thing seems OK  spring and trap all closing  when the throttle pedal is free and opening completely when i press the pedal !!!


 Some body can help me  ?
Thank's
PS : i don't know  the "job" of the part 3 on the pic  ?  it seems to be a switch  and i  think it is ok when i push the piston

« Last Edit: September 21, 2019, 21:56:10 by yves »
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Tyler S

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Re: engine breakdown ?
« Reply #1 on: September 21, 2019, 20:59:54 »
The linkage looks correct. Is the brake booster hose or warm running device vacuum hose disconnected?
1968 (67) 250sl. 4 speed manual. DB180 Silver
1955 220 Cabriolet A. White Grey
2019 E450 Wagon. Majestic Blue
1936 Ford PU Flathead V8. Creme on tan interior.
1989 Volkswagen T3 Westfailia Campmobile. Dove Grey (blue)

jeffc280sl

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Re: engine breakdown ?
« Reply #2 on: September 21, 2019, 21:02:36 »
Damn sorry to hear about your problem.  I believe part #3 is a device to slow/ease the return of the throttle linkage to the stop position.  Without the device I think the linkage would snap back to the stop position.  Maybe you're looking in the wrong area.  These two links are pretty simple and straight forward.  When you were taking the steering box out and in you may have upset something on that side of the engine

yves

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Re: engine breakdown ?
« Reply #3 on: September 21, 2019, 21:55:10 »
You'r right Tyler i'll have a look there , but what is the warm running device vacuum hose  and where is it ?
I have checked all the hoses …. and Nothing seems disconnected …. I am disapointed, and doesn't know which way to solve the issue ?



The problem appears whithout pressing the throttle pedal. Just turning the key to start. May be there is too much air in the mix air fuel ? The engine goes very high in revs  as if i was with the pedal completely pressed  and then it suddenly cuts off as if  a security device  was switched on
« Last Edit: September 21, 2019, 22:03:11 by yves »
Happy owner of a 69 blue 280SL ,  63 FHC  osb E-type , 55 FHC XK 140 to be restored...

yves

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Re: engine breakdown ?
« Reply #4 on: September 22, 2019, 09:21:37 »
Always looking to solve the engine  problem, i found Under the dash a connector which was unplugged and seems to be a switch connected with the clutch pedal …?
I have plugged  it and started the engine …...obvioulsly no difference, but i Wonder what is this switch used for ?

Happy owner of a 69 blue 280SL ,  63 FHC  osb E-type , 55 FHC XK 140 to be restored...

Tyler S

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Re: engine breakdown ?
« Reply #5 on: September 22, 2019, 12:44:56 »
Yes you have too much air entering the system somewhere. Be sure the throttle plate “trap” as you call it is completely closed. There should be no gap between the plate and the bore. If you disassembled the linkage plate/lever on the throttle body and didn't get it back in the same position this could explain it. You may need to adjust it or the stop screw. 

The switch on the clutch pedal is for the fuel cut system. But this wouldn’t necessarily be causing the issue your having.
1968 (67) 250sl. 4 speed manual. DB180 Silver
1955 220 Cabriolet A. White Grey
2019 E450 Wagon. Majestic Blue
1936 Ford PU Flathead V8. Creme on tan interior.
1989 Volkswagen T3 Westfailia Campmobile. Dove Grey (blue)

yves

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Re: engine breakdown ?
« Reply #6 on: September 22, 2019, 13:34:21 »
Hi tyler, i have checked : the trap is completely closed when the throttle pedal is up and opened when it is down
Happy owner of a 69 blue 280SL ,  63 FHC  osb E-type , 55 FHC XK 140 to be restored...

yves

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Re: engine breakdown ?
« Reply #7 on: September 22, 2019, 13:39:25 »
i had a look in the engine bay to see if i have disconnected some thing but all seems to be in place
i don't know what i eed to verify
Happy owner of a 69 blue 280SL ,  63 FHC  osb E-type , 55 FHC XK 140 to be restored...

jeffc280sl

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Re: engine breakdown ?
« Reply #8 on: September 22, 2019, 13:56:19 »
the switch on the clutch pedal is part of the emissions system.  it is related to the fuel cut off valve in that on deceleration fuel is cut off to reduce emissions.  if the fuel cut off switch on the rear of the FIP is engaged after starting, the engine would be deprived of fuel like a security device shutting down the engine.  try removing the wire to the fuel cut off switch to see if it makes a difference,

This link will tell you about the warm running device.

https://www.sl113.org/wiki/Engine/WarmRunningDevice
« Last Edit: September 22, 2019, 14:03:02 by jeffc280sl »

Tyler S

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Re: engine breakdown ?
« Reply #9 on: September 22, 2019, 14:38:00 »
Jeff, that was my initial thought as well but he stated the clutch pedal switch was previously disconnected. There would be no way for the cut solenoid to be activated as the power for that circuit has to travel through the clutch switch. Unless something is miswired or the relay’s contacts are stuck together. Or the enrichment solenoid and cut solenoid wiring reversed. But that wouldn’t explain the engine racing as the enrichment solenoid is only activated durning cranking.
 The cold start valve may be supplying the additional fuel for that brief moment and then the car stalls when it is depleted. But the racing engine leads me to believe there is some sort of vacuum leak as well. IE Car starts from cold start valve enrichment then goes lean and stalls.

Yves, Did you remove or do anything to the linkage lever attached to the injection pump?
« Last Edit: September 22, 2019, 14:55:37 by Tyler S. »
1968 (67) 250sl. 4 speed manual. DB180 Silver
1955 220 Cabriolet A. White Grey
2019 E450 Wagon. Majestic Blue
1936 Ford PU Flathead V8. Creme on tan interior.
1989 Volkswagen T3 Westfailia Campmobile. Dove Grey (blue)

jeffc280sl

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Re: engine breakdown ?
« Reply #10 on: September 22, 2019, 14:58:30 »
Tyler,

Sound logic.  I think Yves feels like he's chasing his tail.  I think we all have been there.  My fuel cut off switch has been removed and my car runs great.  I think removing the wire from this switch is a good step to take.  The results may lead us to the next step.

Tyler S

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Re: engine breakdown ?
« Reply #11 on: September 22, 2019, 15:05:15 »
Jeff, absolutely! Process of elimination.
1968 (67) 250sl. 4 speed manual. DB180 Silver
1955 220 Cabriolet A. White Grey
2019 E450 Wagon. Majestic Blue
1936 Ford PU Flathead V8. Creme on tan interior.
1989 Volkswagen T3 Westfailia Campmobile. Dove Grey (blue)

yves

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Re: engine breakdown ?
« Reply #12 on: September 22, 2019, 20:19:36 »
Thank's Jeff and Tyler …..Job done  :)
ii was thinking that the only thing i eventualy modified was the air intake valve from the air box.
So i have taken out the hose between the air box and the intake manifolds and verify how the valve Butterfly was going closed and opened. I didn't see some thing wrong except grease  and oil deposit around the valve. I have cleaned the valve and the manifold. After i have re checked the opening and closing movement with the throttle linkage.
Started the engine and bingo….. the engine ran without climbing in the revs…. Just the idle too low and the engine stopped .
I have tried some shims between the adjusting screw and the Butterfly lever and found the right adjustment.
Finaly the engine runs quite good at idle .
I am not mechanic and i have tried to adjust the idle with the 2 adjusting possibility see above :


I have first adjusted the lever with the screw 1  and after with the screw 2 .
Is it the right thing to do ?
Sorry for those questions which may be  obvious for  many of you  ::)

PS : i have no more leak at the steering box …. job done but it was hard enough to put in back the box !!!
PS bis : i will unplug the clutch switch tomorow…..
Happy owner of a 69 blue 280SL ,  63 FHC  osb E-type , 55 FHC XK 140 to be restored...

Tyler S

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Re: engine breakdown ?
« Reply #13 on: September 22, 2019, 20:29:08 »
Remove the linkage rod and Adjust screw #1 as the stop for the butterfly valve. It should be completely closed but not hang up when opening. Then adjust and reinstall the linkage rod to the appropriate length.

Start the car and use screw #2 to adjust your idle air delivery.
1968 (67) 250sl. 4 speed manual. DB180 Silver
1955 220 Cabriolet A. White Grey
2019 E450 Wagon. Majestic Blue
1936 Ford PU Flathead V8. Creme on tan interior.
1989 Volkswagen T3 Westfailia Campmobile. Dove Grey (blue)

jeffc280sl

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Re: engine breakdown ?
« Reply #14 on: September 23, 2019, 00:23:32 »
very good news yves.  congrats