Recently started to develope power loss problems at pullaway in my 1990 300e. Car runs absolutely fine after i get past 35 MPH but struggles to get there, basically have to floor it to get any kind of realistic movement. If i pull away with the gas pedel firmly engaged it takes probably 8-10 secs to get to 25 MPH and probably another 5 to get to 35 MPH after that the car runs fine.
Another issue that could be related is that the car starts fine when engine is cold and has been sitting overnight but when i try to restart after a short trip or even after many hours it cranks for longer than usual. somtimes more than 4 seconds. Loss of Gas Milage is also happening due to me opening up the throttle just to move the thing !
It's hot here in Phoenix at the minute so she is running a little hot in stop and go traffic with the A/C on full but that is to be expected. freeway driving she sits at just aboce the 80.c mark.
A list of things done in the last 6 months
New plugs and wires
New rotor and distributer cap
New Coolant res
Coolant Flush
Transmission Flush
New water pump
New Coolant temp Sensor
New front pads and rotors
New A/C compressor
New A/C Dryer
R134 Conversion setup
A lot of people have exacly the same issues with these 124's I wish they designed them a little better to avoid these problems. I my self have the same problem. I replaced teh Engine harness, plugs, wires, all that electrical stuff, and still it just wont take off as a Mercedes should, my next step is to hook it up on a computer and diagnose from there.
I'm with you there, I don't expect her to take off from 0-60 in under 5 seconds and i also appriciate that the car weighs a ton and it not made to be ripped around like some honda but the pull away power i am getting at the moment is just completely unaceptable...... i hate the fact i'm having to floor the gas just to get some decent movement. any other comments would be great..
I'm going towards the fuel injection compartment next, I'm guessing it has something to do with fuel distribution, have you replaced any electrical parts? such as e harness, coils? Your cheapest repari would to to replace the plugs, I put platinums in mine they seem to be giving me better performance, even though they are highly not recommended by the benz whiz.
I have a feeling that maybe the next stage would be injectors, have seen some posts of injector replacement with huge economical and performance benfits.. have replaced the plugs with plats +4 even though as you stated they are not recomended but i can't see them being the source of the problems we are having, i'm pretty sure it's a fuel delivery problem. problem is it could be any one of the below or even multibles:
Maybe it could even be a fuel/air mixture issue but i'm definately not playing around with that, i will leave it to the pro's if all else fails. but regardless i have run chevron techron and all the other recomended stuff through the gas tank and i have not had any inprovement. I got this car 2 years ago and it started stalling 6 months in, i sunk alot of the fuel additives and it helped and then i changed the plugs and wires and the stalling when away and performance was much better, then the a/c went out so i was driving around in winter with no A/C and performance started to die again so i changed the distributor and roter and this helped alot, seem's ever since i had the A/C compressor replaced that the pull away performance of this car started to drop drastically. has your issues been with the car since you have owned it all just come along with age ?
Also it also seems that when the engine has heated up it gets worse, if the engine is cold it does not seem to be almost near as bad ? Are you getting the same as me ?
Go under the passenger carpet and disconnect the O2 sensor. If the car gets it's initial stepoff pep back, you might try changing the sensor. I recently replaced mine and all is well now. I used one for a 90 Mustang GT and spliced in the Mercedes plug.
front pass or rear ? Is it under the carpet or do i have to pull out the insulation aswel ? I thought you could only get the the 02 sensor from underneath the car ? Another quest, why did you use a mustang sensor ? price or compatability ?
The sensor connection is under the front passenger carpet. Just pull the carpet up, the insulation is attached to the carpet. You will see a purple bundle coming from the transmission tunnel. Follow that to the O2 connections. There are two. One single and one double. Disconnect one of them... By doing this, the "check engine" light will come on after a few minutes of driving. Don't worry about it, just see if the "bogged down" problem goes away.
I used the Mustang O2 sensor (bosch part) as it was only about $30 vs. $150 ish for the Mercedes part. In other threads, I've read that this is an OK substitute, as both are "three" wire sensors. Wire colors match up. Two white and one black.
The sensor itself is located under the car on one of the two exhaust pipes. There is a protective shield on the leading side of it that just pulls off. If you decide to use the substitute sensor, cut the Ford connector off just behind the plug. You will need all the length when making the splice to the MB plugs.
I found the two connectors under the floor mat were you stated and pull the single wire lose from it's connector and what do you know........ No hard starts and she ran much much beter.. no hard pull aways and much more power with less presure on the gas pedal.... Thanks Man. Villi have you tried the o2 Sensor yet ? I think its worth a shot if you havn't..... Have a few more questions ......
How long can i drive the car for without the o2 sensor connected ?
My check engine light did not come on after this but i suspect the bulb has gone or is has been discontected as i does not even light up when i turn the keys to start her, never has ! But i checked my Dionostic readings box next to the battery "16 PIN" and it give me fault codes 11,13,16... Does anyone have the readings for these for a 90 300E ? Beleive its the m104 Engine Unit
Glad you are underway with better step off response. I am not certain how long you can drive without the O2 sensor connected. If I am not mistaken, the fuel/air mixture is rich w/o the sensor connected. Check you gas mileage for a week or so and see.
If you are driving a 90 300, I suspect you have the M103 motor. Is it a single cam engine with the plugs running down the passenger side of the head? If so, it's a 103. In 90, I am pretty sure MB introduced the twincam M104 engine in the 300CE (which is what I drive) and I am not certain if it was available on the sedan.
Good Luck and I am glad the "short cut" worked out.
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