I started the car, and went for a 4-minute drive to the video store.

When I re-stared the engine (must have been turned off for 2 minutes max) it fired up as normal, but when I released the accelerator it didn't idle at 800 rpm as usual. It just dropped to 0 and stopped. The "Check Engine" warning light was on all the time.
I could re-start the engine without any problem, but it would not idle. It just stopped if I released the accelerator.

I parked the car and took out the DME relay, looked at it… and didn’t know that the hell to do with it, so I put it back World-class mechanic I am not.

I also checked the DME fuse. It was ok.

So, I drove home and as I arrived the "Check Engine" warning light turned off and suddenly the engine idled at 800 rpm.

What could be the problem?

Should I change the DME relay?

PS. I washed the engine with a high-pressure cleaner on Friday, but have had no problems yesterday

 

Not sure if the DME relay is your problem, but as good measure, I would certainly try replacing it and go from there. If its not your problem, you'll then have a spare..

Sorry I am not more help..

 

I doubt it's the relay - if it was, it wouldn't run at all and wouldn't just affect the idle. Worth having a spare anyway though.

Unfortunately - I can't offer many other suggestions that affect just the idle. The idle microswitch maybe? But I suspect this doesn't cause a check engine light.

 

Have you always started the car with the gas pedal depressed?

 

Often the oxygen sensor will get wet if it's a cheaper part and fail.

A failing oxygen sensor won't let you idle well, and will trigger the check engine light. Read out your error codes and keep us posted!

As Jason mentioned, you should be able to start without pressing the gas pedal.

I'll bet your oxygen sensor is bad/shot.

 

Guys,

Thanks a lot for the advice.

Last night I had a look at the engine. As mentioned earlier I'm not a great mechanic, so I got little further than looking. Did a fair bit of cursing as well. I did manage to take off and clean the plug for the idle sensor, though.

I also unplugged the DME and looked at the connector pins (looked fine). Then I and went for the required 15 minute spirited drive.

When I got back from a very spirited drive, the car would idle around 1000 rpm. Before the problem arose it used to keep itself around a steady 800 rpm.

This morning the car idles fine at 800-900 but the Check Engine light stayed on for about 2 minutes after I fired up the engine.

Now that I come to think of it, the car was slightly overfilled with oil about a month ago. I had a leak in the oil line fixed and the mechanic must have gotten carried away. I took out approx one litre of oil.

This afternoon I will buy a new DME relay. Let’s see where that gets us.

I’ll keep you posted.

PS: Garrett, as far as I understand, I can't read out the error codes using the Check Engine light (my car is not a US model. it is Swiss). I put the bulb in the "Check Engine" light myself.

Do I need a Hammer, i.e. a mechanic who has a Hammer?

 

Jens, an overfill of oil can cuase idle problems because it could have contaminated the airflow sensor...check everything over thoroughly...

 

Jens,

I had a similar problem i posted about a few months ago. My car would idle roughly but only very intermittently but then one day at work refused to idle. I could start it on the key with foot on the gas but it then died immediately. I got it carried home and managed to get it started but the problem persisted. I also tried all the replace DME, clean ISV etc but to no avail. I used to also get real fluctuation on idle now and again both when warm and cold. Even tried replacing the fuel filter!

It turned out to be a faulty O2 sensor as mentioned here and read as an error code on the hammer showing that whilst it had'nt completely failed it was reading beyond its limits. This will totally destroy the idle. I also had the Distribitor caps and rotors replaced as they were 10yrs old. After a hammer reset all has been fine for the last 10weeks. Not a cheap fix unfortunately but worked for me.

Hope you get it sorted

Cheers
Giles.

 

Latest news,

I just put in a new DME relay... no change.

The engine still stalls most of the time. Now and then it will stay alive maintaining an un-even, very low idle (swinging between 300 and 500 rpm)

When it does stay alive, it helps a bit to turn off the air con.

Anyway, I guess the O2 sensor is the next step. I will drop the car off at the garage where I bought it. (Warranty still valid)

Will keep you posted.

 

Jens

Just remember that if the car does NOT idle from cold then it is unlikely to be the O2 sensor - this does not come in to play until it has warmed up...

 

Yes, but I think it is warmed up after only 90 seconds when it has gone through its self-warming cycle so that can be hard to tell - especially if he's using the gas pedal to start the car

 

Yes, for 90 seconds or so only. And why use the gas pedal?

 

Oops!

Sorry that I forgot to answer Jason's question. For the record, I never touch the accelerator when starting the engine, and I always let it run for a few seconds before revving it up.

I will let you know what the mechanic says tomorrow. Considering that somebody at the same garage overfilled the oil, I'll be on their backs like a fly on a sh*t this time.

 

Here is an up-date from the mechanic who is taking care of my car.

He says he checked the Idle Micro Switch and the Air-Flow Meter and found no problems. He also says the O2 sensor is OK. The work goes on tomorrow.

Now, after speaking to him I remembered the air box. I drilled 4 large holes in it about a month ago, and never experienced any idle problems afterwards. Last Friday, I took it one step further and cut out the whole face off the air box with a Dremel tool (only leaving the frame to hold the air filter). See picture.

The car ran perfectly all day Saturday (went for several drives), and the idle problems only occurred Sunday. Could it be the air box?

 

What fault codes did you have stored in the DME?