bad vibrations

[ajg72]

My car is idling poorly. It noticeably vibrates and rocks side to side about an inch or two at idle but doesn't stall. When I accelerate, the vibration decreases but is still there and i have a slight loss of power. I initially thought misfire but when I do a stomp test, I get a 1444 code. I then started to disconnect coils one at a time to see if the idle changed and i found coils 1,2,3 to not change the idle and coils 4,5,6 do. I like to think I know a little about cars since this is my 3rd BMW but need advice b4 i go to an indy.

To give everyone overall view of my car

-94 525im
-209k+
-new plugs/boots, valve cover gasket,transmission, trans&motor mounts, fuel,air, oil filter
-intermittent 45 codes(about once every 2wks)on scan tool which is misfire on coils 4,5,6
-never had any major idle problems or stalling
-original suspension components to be addressed shortly

-i have always had a little trouble initially starting the car the first time of the day which caused me to change the ff but is fine afterwards.

[ajg72]

anyone?

[Jon K]

Bad DME?

[Morgenster]

Hey, it'd help to know under what circumstances this happens. For instance: does it happen when the engine is cold/warm? What idle RPM are you getting when it happens? does it happen only with clutch in or out?
Anyhow, it could well be the wires leading to the coils are damaged or the output at the ECU is compromised since they are grouped by three.

[ajg72]

It happens all the time hot or cold, clutch in or out, and through the rpm range. The idle is about 500 rpm and will sometimes go back to where it normally was but will still vibrate. I checked coils 1 to 3 for resistance and they are in spec (0.5,0.5,0.7) and also checked all three connectors and they all had voltage although i did not have a multimeter to check actual voltage. I didnt notice anything while driving the night before and the next morning i started the car, the problem started

[Morgenster]

Could be oil in plug well, bad dme signal, or bad coils but it'd be weird to have all three fail. unless it's fuel delivery problems, but I don't see how that would lead to such a rumble. I'd take a look at the conector at the dme side.

[Sam-Son]

does the problem go away after driving it?

[ThoreauHD]

Umm, not to state the obvious but were you planning on replacing the ignition coils after 202K miles? They get cranky at 100-120K. And if you remove the bad one, and the problem goes away.. then... anyhow I'd do the bavauto ignition coil set with wire harness.

[ajg72]

Could be oil in plug well, bad dme signal, or bad coils but it'd be weird to have all three fail. unless it's fuel delivery problems, but I don't see how that would lead to such a rumble. I'd take a look at the conector at the dme side.


Where exactly is that?

The vibration is nowhere as bad as speed but it is still noticeable. When the car is at idle the whole car shakes.

Thanks.