Accelerator stuck on full at start-up

[sharky1]

Hello everyone I am new MB member just joined!!
I have a problem can anbody help me,
Just bought 250 diesel 1995 Auto/ I changed from 1994 200 petrol Auto/
My problem is this, drove car for few days/great improvement over 200/ driving great until today that is, switched off engine after returning home/decided to go out again turned on ignition without foot on accelerator and engine accelerated excessively in park lucky enough I switched off engine checked usual accelerator cable & mechanism everything fine, tried repeadtly same symtoms? cable is not kinked or even getting stuck? can someone shed some light on cause. Cannot start merc without this happening just jumps straight up to full acceleration cannot find fault, used to work on petrol mercs quite a lot never came accross this before?
Please help

 

[brandwooddixon]

You could try resetting the adapted throttle position.
Turn the ignition to point 2 (the furthest without starting the engine)
Depress the accelerator to the floor for a few moments, but don't trigger the kick down.
Leave for about 2 minutes and turn the ignition off.
Then try again.

Only other worry would be oil getting into the manifold, say from the turbo charger.

 

[sharky1]

Hi Chris thanks for help I will do what you advise, I meant to state that I have a non turbo model though?
1995 E250 Diesel Automatic

 

[sharky1]

No luck with what you suggested chris I have tried everything I can think of I have tried cleaned butterfly flap checked all vacum connections and hoses, checked all electrics etc no prior warning of this problem car was driving perfectly just cannot figure it out any other suggestions for me to try would be much appreciated
Regards Sharky

 

[sharky1]

I still have a major problem can anbody help me,
Just bought 250 diesel non turbo 1995 Auto/ I changed from 1994 200 petrol Auto/
My problem is this, drove car for few days/great improvement over 200/ driving great until today that is, switched off engine after returning home/decided to go out again turned on ignition without foot on accelerator and engine accelerated excessively in park lucky enough I switched off engine checked usual accelerator cable & mechanism everything fine, tried repeadtly same symtoms? cable is not kinked or even getting stuck? can someone shed some light on cause. Cannot start merc without this happening just jumps straight up to full acceleration cannot find fault, I hav checked for all vacum leaks etc/ I have even tried resetting cable throttle. I havent changed anything in engine etc before this happened/What can make the eccelerator jam fully open at start-up? throttle mechanism is working ok no sticking, cable fine, throttle mechanism does not move when car is started at start-up accelerator is not touched yet roars into life doesnt stop revs go off the clock if engine is not switched off????
PLEASE PLEASE PLEASE HELP ANYONE
HAPPY ST PATRICKS DAY TO ALL MEMBERS
FROM SHARKY

 

[panason1c]

It could be a 'governer' fault within the injection pump that is causing full throttle actuation.

Might be an idea to speak to your local Bosch injection agent.

 

[sharky1]

Thanks
Will do
Do you think it means new injector pump
or can a repair be carried out?

 

[panason1c]

More often than not they will probably recommend a factory rebuilt exchange unit.

 

[Parrot of Doom]

Is yours a drive-by-wire version? Cable terminates at a potentiometer at the back of the engine bay?

 

[panason1c]

Is yours a drive-by-wire version? Cable terminates at a potentiometer at the back of the engine bay?

I would think a 1995 model is too old for drive by wire.

 

[sharky1]

I really don't want to be fitting new injector pump unless absouletly necessary, is there anything else that may cause such a problem?

 

[sharky1]

Don't really know if mine is a drive-by-version or not? is that the injector type?I know there is no electronic sensor attached to MAF like in some models i have seen only a vacuum controlling butterfly at air intake unit. I really don't want to have to change pump only if absouletly necessary for abvious reasons

 

[sharky1]

My Mad accelerator

Realy don't know what version it is, I really don't want to have to change the injector pump only if really neccesary for obvious reasons, is there any other components that I can check that may cause such a problem?
rgds sharky1

 

[panason1c]

If your throttle cable runs from the pedal and goes directly all the way to the injection pump then you DONT have the electronic 'drive by wire' version.

If, as you say, the throttle cable is working freely and is not holding the inj' pump open then i cant think of any reason other than the inj' pump itself being faulty.

You really need to let an injection specialist look at your car, or describe the problem over the phone, for an accurate diagnosis.

 

[sharky1]

Thanks for all the valuable information as I live in a small town in Ireland I don't think it will be that easy to get a very acurate diagnosis but will do my best, unfortunate that I had the merc only a few days when this happened so didn't avail of much pleasure driving it, I have had a petrol merc for years e200 1994 with virtually no problems what so ever over the years still have it but nor very economic.

 

[sharky1]

Still no luck with mad accelerator at start up

I have tried all advice from members and I truly Thank everyone here but stll no joy problem still remains have just been told about idle speed solenoidat back of pump that may be causing problem I am just going to check this out and the info I got concerning it, if I am real lucky and this works out I will post the fix shortly and will include pics later on this week
Maybe I am jumping the gun but who knows maybe this is the problem
Rgds
Sharky1

 

[panason1c]

Hope it works out for you but i suspect that the solenoid you refer to is the fuel cut off solenoid which cuts off the fuel supply to stop the engine when you switch off.

 

[sharky1]

No look with fuel cut off solenoid, that didn't solve anything, problem still remains engine revving up as fast as it can at start-up. I have tried everything everyone advised but to no avail.

 

[merc convert]

Maybe someone with more knowledge can confirm this, would disconnecting the battery reset the ECU to factory settings?

 

[sharky1]

Hi everyone Just to say Thanks to all for your invaluable knowledge & assistance in helping with my Mad accelerator ata start-up
Well I sure hope its cured now. Yesterday I was kind of resigned that I would be changing the Injector pump which I didn't wanty to have to do as the expense of this would be pretty high. So I decided to again check all Vacuum lines & pumps but this time I disconnected and reconnected all. When I arrived at the Injector pump vacuum lines when I disconnected vacuum pipe at the top of Injector pump the one that looks like a black coloured plastic bottle top with a pipe inserted in its top, not to be confused with the vacuum line thats connected to a metal type disk (flying saucer like) at the rear of Injector pump, Anyway I disconnected vacuum pipe from top of injector pump and extreme air escaped and I mean extreme, I reconnected pipe and turnrd the igniton fully, merc started normally first go with normal revs and acceleration, returned to text book revs when fully warmed up. Merc now has got plenty of power very responsive, no flat spots or untold acceleration problems, engine tickover very smooth no vibration or shaking. Has been tested extensively over the last 24hrs and all is behaving itself. I must admit that it is driving superbly. Just wondering if anyone experienced simular symtoms like these in the past and sourced what had caused such problems. Just wondering is this a precussor to further problems down the line or is it that some where in the vacuum lines there was some sort of leak and now its cured.
Anyway I would just like to thank all members that contributed in assisting me in tracking down my problem.
Thanks to all for contributing your invaluable knowledge and expertise expertise with out it I would have I think giving up before now. Just having a forum like this is so reassuring as a Mercedes owner, Before now I thought of Mercedes Diesels as some kind of un-known Dinosaur best well left alone but my opinion is slowly changing according as I gain sme knowledge on the subject Thanks to everyone here of course. I only hope that by contributing some little knowledge here helps someone else in a pickle like I was.
Thanks again all members for sharing your invaluable knowledge
Kindest Regards
Newly Discovered Dinosaur species owner
sharky1