Ok, this problem has been occurring for awhile. This car used to be my sisters, but she got a new malibu, so I thought I'd drive it around and see what the problem was to hopefully find the problem. Here's what the car will do at times. Sometimes when first starting it, usually when it's cold. At idle the rpm's will go below 5k and of course shut off. Sometimes it will stay above, but once you shift in to reverse it will go below 5k and will shut off. To prevent this you have to brake and keep the rpm's up while backing out. Sometimes it will do the same thing in 'drive'.

Another thing, when pulling from a stop I'll press the accelerator and maybe for about 10 seconds, I will just inch along. It seems like the car wants to quit on me, but by keeping the accelerator barely pressed down, it will eventually just take off. The longest it has done this for is about 30 seconds, right in the middle of the intersection (quite embarrassing, lol)

And last, every once in awhile the Check engine light will come on. When it does this I noticed the speed will go down, just a little bit. It feels as though you were shifting your car down to 3rd gear, how it will somewhat jerk and slow down, but it is not quite as drastic.

I'm hoping to put some money in this car, but not sure where to start. I hope you guys can help me pinpoint these issues.

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1986 560 SEC *Sold* < Big Mistake I miss my baby!
1988 300SE *Sold*
1989 300CE - current car, but not for too long

Snoopy572, when was the oxygen sensor last changed? Our 1991 300CE had similar symptoms, though not as severe. Replacing the oxygen sensor eliminated the hesitation. You should also check the condition of the distributor cap, rotor, ignition wires and the spark plugs. The fuel filter should be replaced every 60,000 miles. If you're not sure when the fuel filter was last replaced I'd have it done as preventive maintenance.

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Fred Hoelzle

I concur with Fernad...


Also check the Over Voltage Protection relay (OVP)... If you do what Fernad said and you still have the same or similar low idle problem, buy a new OVP and it should cure the car like magic... (should, but might not)

You can learn more about the OVP relay by using the search function for this forum.

Good luck, hope you can fix er' up!

Awesome, thanks for the tips. I will start by trying the above.

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1986 560 SEC *Sold* < Big Mistake I miss my baby!
1988 300SE *Sold*
1989 300CE - current car, but not for too long

Also, not sure if this will further help diagnosis, but sometimes (often) when I first start the car, it will keep trying to start but after like 5-7 seconds it will turn over, hesitate then fire up. Sometimes it won't do it the first time (I'll leave the key in the start position for a few seconds and it will just keep trying to start), so after put the key back in regular position and try to crank her up again, it will do the trick after another few seconds.
Thaks for the info though. I can't want to get these problems resolved.

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1986 560 SEC *Sold* < Big Mistake I miss my baby!
1988 300SE *Sold*
1989 300CE - current car, but not for too long

Yeah, just make a good practice to leave the key in ignition position 2 for like 3 seconds before starting up... you know when all the dash lights come on and you hear a brief hissing/ priming sound (fuel pump getting ready for start up),

it is just a very good habit, the car is more ready to start up if you wait a little time in that position....

Well, I totaled all the parts up that were suggested and the total came to $546.79 including a radiator. I will have about $1000 to put into the car at the moment. I am really hoping those few items will take care of the problems I'm having. I figure labor will be another $400-$500. THat will set me right at my budget.
Here's the part list:
Oxygen Sensor
Overage Relay
Distributer cap
Distributor Rotor
new Plugs
Fuel filter
Ignition wires
Radiator.

I figured I'd just take care of everything at once, since I'm not sure when these parts were last replaced.
Please tell me if there is anything I am missing or if there are any other suggestions regarding the problem I am having.
Thanks so far, it's greatly appreciated.

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1986 560 SEC *Sold* < Big Mistake I miss my baby!
1988 300SE *Sold*
1989 300CE - current car, but not for too long

everything you describe is very do-able yourself..... save the money..if you don't have the tools borrow them or buy them.

Dear Snoopy572,
We both have the exact same problem/symptoms with our cars. What you have described is exactly what my car did. The electronic part that kills the engine is the idle control valve. I disconnected it. The vehicle does not stall any more and runs like a dream.

Before you go out and spend any money do the following. Remove the air cleaner. Once removed, you will see the idle control valve (looks like a 3 inch long cylinder). There is black wire on the idle control valve. Disconnect this wire.

The previous owner of my car spent at least $1000 trying to fix this problem. The mechanics changed everything from O2 sensor to fuel injectors and they still could not figure out the problem. She got fed up and sold it to me. My advice is try this first. I have been driving my car with the idle control valve disconnected for almost a year. I had bought an OVP but turned out to be the wrong one (For a 190E). If the problem persists take the car to the Mercedes dealership. They charge $90 an hour but they know what they are doing. The previous owner of my vehicle took it to a regular mechanic who charged her all the money but still could not fix it.

As far as I can tell you will need a new OVP. Let me know if a new OVP solved the problem, and also if disconnecting the idle control valve does anything.

(See my original post for drawbacks of removing the idle control valve)

FS

I'd be more than happy to do everything myself and think I would be more than capable of doing it, although I've never worked on a car myself before. What tools would I need to get the job done? Would be a fun experience. Worse case scenario is my tech would have to clean up what I did.

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1986 560 SEC *Sold* < Big Mistake I miss my baby!
1988 300SE *Sold*
1989 300CE - current car, but not for too long

Thanks for the tip, I will try that and see if I can notice any differnece. The crazy thing is that it has stopped stalling and turning off on me. Like I said, it has a mind of its own. It hasn't been too cold lately, but I'm not sure if the weather has an affect on it or if it's just a coincidence. At any rate will try the above tips.

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1986 560 SEC *Sold* < Big Mistake I miss my baby!
1988 300SE *Sold*
1989 300CE - current car, but not for too long

Sultan... put your idle control valve back in your car along with a new OVP relay and your car will purr like a kitten under any idle load. The two work in conjunction with one another.

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Earl



1993 190E 2.3
2000 Toyota 4x4 Tundra