Acceleration-like problem

Guten Tag, I have a 1989 Mercedes-Benz 190E 2.6, with some 160 thousand miles on it. I don't know how long the problem has been occuring, if it was progressive or if it was more instantanious. In any event, the basic problem is that if I press on the accelorator after coming to a stop the car hesitates as though it is not getting enough fuel. If I am on the highway and I floor it I get the feeling that it is not getting enough fuel as well, and if I back off the pedal I get more power. It also idles rather low, and when put in gear the idle becomes progressivly lower. I have removed the air flow sensor, and given it a through cleaning, replaced the fuel filter, and the cap, and the roter, and the plugs. If I disconnect the idle air pump it idles higer, and than if I reconnect it while the car is running it dies. But I can instantly re-start it. Currently I have the cable for the accelerater adjusted so that the idle switch is not contacted, and the car runs better. I hope I have provided enough information and I hope that someone can help me. My next ideas are that the over voltage protection relay may be to blame, if I shake it, it rattles. But the car runs without it connected.

As I drove home tonight I considered the possibility that the old wires may be arching to oneanother. I had noticed a strong smell of gasoline, and it may feel as though not all cylenders are running. So I'll give it a go, and let everyone know.

-Andrew

[mctwin2kman]

When you pull the OVP Relay does the idle change? Have you checked your plugs, wires, cap and rotor? When was the last time they were change? Next test you O2 sensor as well. I am betting the OVP is bad since you said it rattles. I have two and neither ratter or make any sound when shaken.

I changed the cap and roter afew hundred miles ago. The wires look older than dirt aka: original. Idle does change when I unplug the OVP. But it could still be a culprit. Another notion I am entertaining is the air pot. On my old 2.3 their was a bit of play, in that it could be pushed down about a centimeter or so. However on this car that flap has no play. Which could lead to problems with the fuel distributer. I can "help" the flap up. But it does not have that "spring" action that the other car, and my neighbors 300 E has. Comments? Suggestions?

[derryb]

how old is fuel filter?

Just replaced it, was not the problem.

Any more suggestions?

[ron@rydinterior]

I just purchased a 1990 300 E and having the same problem. when I purchased the car it ran fine, but missed inspection by .o5 on the oxygen test?? so the technician said to put fuel injector cleaner into the gas tank and come back and it should pass. well I did and now I am having the same acceleration problems, you give gas and it putters, and if you push it, it will eventually stall but will start (usually) right up. please if anyone knows what to do please tell us! I'm affraid to drive it knowing that I may break down!!

[JoeR]

I'm having a similar, but intermittent, problem on my daughter's '87 300E.

In troubleshooting, replacing (O2 was due at 282,000 mi. and filter) and checking various things, I decided to unplug the EHA and see what happened. The problem has yet to happen, so that eliminates a number of possible items, including fuel supply and ignition. I have to find time to get back to it, but now I can isolate the problem to anything related to the electrical fuel injection control.

Good luck! Any anyone who finds a solution, please post results!

[ron@rydinterior]

Hey Joe, I know next to nothing about cars, what is 02? and what is the EHA? where do I find it so that I can unplug as well. also if I unplug it can I still drive the car?
thanks Ron

[JoeR]

O2 = oxygen sensor, located on top of exhaust.

EHA = electro-hydraulic actuator, black box on rear side of fuel distributor with plug.

[ron@rydinterior]

thanks Joe!!

Ok so I have replaced the wires and the OVP relay. Car still does that thing where if I floor it, it hesitates, and runs not so well. Could it be the EHA? Or perhaps the teperature sensor? Who can help???

hopefully this will be helpful

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I had a 88 300E .when the hotter weather came the car started to stall for no reason.changed the voltage regulator , a few other things.Make the long story short..someone at mercedes told me to take out the computer(behind the battery , under the hood) The car will start up in a kind of safe mode(higher fuel consumption, slower acceleration but IT WILL GET YOU HOME!!!...lol BTW show me another car which will do that!!!) Now if you drive the car around for a day or 2 and the stalling doesnt reoccure, the problem is 99% with the computer.You can get a new one or used one but what i did is......... (i remembered that german printed circuits gave my problems already before ,poped up printed circuits,loose soldering joint,)...took the comp out,seperated the 2 inside panels and reheated all joints ...appr 200.....and drove the car for another 150000 no problem.But thats just how i solved it.

[Nateuton]

Hey I was having similar problems with my 91 300E, it seemed to be something in the Idle control circut. But on yours it might be the injectors??
I replaced mine to no avail..
I replaced my cap and rotor, deffinately needed, but no differece.
I replaced the EHA, it was leaking, no difference.
I replaced the OVP, no change, but more about this later.
I pulled of the idle conrol valve and ran 7 volts through it to check and make sure it was working, and reinstalled it.
ONLY then did the car start acting right.
I don't know if it was the combination of a new OVP and testing the ICV or what...
I put the old OVP back in (it rattles) and it does not make a difference, so hard to say.
It has been suggested that the "Potentiometer" might have been a problem, but I don't think it was in my case.