1991 300e Slugish gas pedal
 

This is not my car, it is a friends car. She bought it new a long time ago. Car has been maintained (with records ) at the dealership since the day it was bought, awesome looking and driving still after 180,000 miles.

recently, the car developed a problem where you hit the gas, with minimal response, and and you need to really floor it to get engine to respond. it is very sluggish and lacking on power... the dealer took it in and started changing parts left and right but did not cure the problem. they suspected and changed the o2 sensor, nothing improved. the then they suspected the distributor cap, wires and plugs, and nothing improved. after a $1500 bill, they still wanted another $1000 to change fuel pump because they "think" that might be the problem..i told her to cut her loses, and that i will diagnose and repair the problem for her with the help of the forum, because the way the money adds up at the dealership is ridicoulous (the actuall bill was $2500 because the changed the rear sub-frame bushings also...WAY too much)......

any how, i do think this is fuel related, but i am also suspecting the transmission/ torque converter... it shifts great with no problems or delayed engagement in any gears, but i noticed it is a bit harsher now changing gears since last time i drove it last year...but this could be a whole separate issue....

so bottom line is that car is sluggish as hell, and you need to really hit the gas hard to feel the car open-up and fly.....where to start diagnosing this problem?

thanks,

Sounds exactly like the EHA is the culprit as I have the same experience when I first got my 260E. You can try giving it a turn rich and see what happens. Two bolts and its in your hand (air assembly off)...Then undo the screw on the back and use an allen key to turn clockwise...Based on what you are saying I'd go for a full 180 turn. Close it back and go for a spin. If it seems more responsive you got the culprit.

Of course it could be bad injectors, but this test is free above. If you see no difference, CHANGE IT BACK!!! Make sure you record how far you turned it. Clockwise = richer, Anticlockwise = lean.

180k is a lot of general wear on the fuel system. Have you also tried seafoaming her? Might be a good one as well for a general item to do.

latief, your friend must be a soft touch. Why would anyone pay for repairs that didn't resolve the sluggish peformance. Encourage her to take her 1991 300E back to the MB dealer and insist that they resolve the problem. If it were me I would never have paid for the oxygen sensor, distributor cap, rotor and spark plug replacement if the problem still existed. The fuel filter seems like a possibility; but a qualified, experienced tech at a MB dealer should be able to diagnose a problem and fix it before even considering returning a customer's car.

Replacing the rear subframe bushings to pad the bill and not resolving the sluggish performance is disgraceful. I would be having a heart-to-heart discussion with the owner of the dealership.

Ouch, that hurts. Agree with Fred's view; the dealer owes your friend better than that. It could be EHA (it controls fuel adaptation ratios) or possibly even throttle valve switch (controls wide open/full load throttle response). The point is, a capable tech would start with standard, well-known diagnostic tests to see what's causing the symptoms.

For the future, you have two highly-regarded independents in your area that would surely do a more competent diagnostic job than what your friend got at the dealership. Steve Brotherton's Continental Motors in Gainesville and Pierre Hedary's shop in Titusville are well regarded by knowledgeable Benz owners. One or both may even give a courtesy discount to MBCA members. Once your friend gets the dealership to provide some gratis repairs out of this, bid the dealership adieu.

Thanks guys,

you know how people think that the dealer knows best. the funny part is that the bill was after a %10 discount because she is driving a 'vintage'. they also give her a loner vehicle and she is a very busy person.....( i told her you paid for the loner!!)

the parts that were changed are regular maintenance parts that should not cost that much in any way. I told her about Steve Brotherton's shop before, she said she take it there next time (once she recovers from the $2500 bill)....

so, i want to diagnose this problem, but my experience thus far has been with the 104 engine and HFM ignition on my car...

can you tell me what EHA stands for so that i could look it up the mercedes manual. i will give it a shot and see.....

so fuel pump/pumps are not the culprit in your opinions? I was thinking injectors also, but i thought those would be more of a misfire situation as opposed to an overall lose of power....

more opinions are welcome, thanks

Electrohydraulic Actuator. Used on CIS motors. Search on EHA at the top of the screen. Tons of threads.

thanks!