Engine Trouble. Help!

[Marknhl]

So as I was driving home tonight, my 94 325IS that is on cruise control at about 75 starts sputtering out. Or something. The rpms would for a split second rapidly drop or sometimes increase and the check engine light would flash at the same time. The car would shake and slam with the change in the engine too of course. So I pulled over and went to check the engine bay. Oil looks ok, but there is a somewhat odd smell. Possibly oil, idk I have a horrible sense of smell, let alone ability to tell what I'm smelling. Plus it's late and I'm tired. So I go to take off again and if I get over 2000 rpms it does it again, the car and engine shakes somewhat violently and sounds horrible. The engine sounds loud but I don't think it's exhaust. I ended up driving home at about 45mph, anything over that would cause problems. Does anyone have any ideas what this could be? It sounds major but I'm really hoping not. I only even have the car out because my winter car's exhaust system rusted out....... Thank you in advance for the help.

[Marknhl]

The car has been sitting for the past two months or so without much attention. Perhaps this will help clarify the error. It would be great if it were something so simple as bad gas from sitting around but I fear it is something much worse.....

[thekid]

Bad gas could be the culprit. You could try filling up at a known good gas station and then using some fuel treatment additive.

[nukeduster]

is it vehicle speed dependant or engine rpm dependant?

is it a bang bang, screech, grinding, clicking, what kind of noise and duration is it? does it get louder as you go faster/higher rpm, or does it stay the same noise level after it starts no matter what else you do..

if the vehicle is high milage, have the spark plugs been changed alot before? even if not, someone before may have over torqued them and stripped out a spark plug hole and a spark plug got blown out of the cylinder.

without more info im just casting magic missile into the darkness.

[Marknhl]

Yes but hopefully your magic missiles are close to the target. I just looked at the spark plugs a couple months ago and there had been an odd clicking in my engine since I bought it that was caused by a loose spark plug. What a difference tightening had made! However, my buddy looked at the car and he says it smells like the engine is dumping mass amounts of fuel into the car and that it is causing smoke to come out of the tail pipe. He is guessing that a coil pack went bad. It seems to make sense and I hope it's something that small. In the next couple days I'll be taking that apart, possibly replacing all the spark plugs and at least the bad (assuming one is bad) coil pack. The noise isn't a clicking or a banging, its just misfiring if I understand correctly. We looked at it today and it would hardly stay running. Thanks for the help, I"ll update after we take a look at it.

[seven]

If a sparkplug came loose it is possible the blowby or the plug itself has damaged the coil.. Seems m50 motors are bad about loosening plugs hope your threads were not stripped out Good Luck

[skytiger]

A long shot but if it starts and runs ok until you get it under load, have a look at the large rubber hose between the airflow meter and the throttle body. If you have a split in there (quite common on older cars) then you will get all sorts of problems. The airflow meter will be telling the ecu to operate with a given amount of air. If air is getting in after the afm has taken its reading then it will run like a tumble dryer full of Dr Martins.
Otherwise you could have faulty coil pack/s

[Marknhl]

So I took all the coil packs out of my 92 parts car and replaced all of the ones in the 94 that I drive regularly. Same problem. Four of the spark plugs looked like they had gas on them though, and two others didn't appear to have any on them. Fuel injectors?

[Marknhl]

Tried starting the engine with one spark plug out to see if it had spark... didn't work either. Although I tried this with two cylinders and neither one sparked. I don't think this is the proper way to be testing the coil paks or the spark plugs. I'm really stumped on this. Does anyone have any thoughts? Thank you.

[94BMW325i]

if your car was bogging like that, sounds like you aren't getting spark.

[Marknhl]

takin it to the dealer for inspection.... after they tell me what the problem is, I'll do the work myself. The amount that i pay them to look at it will be sufficient to take care of them regardless of whether I have them do the work. Rip off lol

[325iS]

Clogged fuel filter.... you're not getting enough fuel under load.

[Marknhl]

Turned out to be a bad DME. I also replaced the crankshaft position sensor previous to that as the dealer said that was another suspect. However, now my ASC and ABS lights are on and I don't know why. Gotta figure that one out still... is there a computer you can hook up to the car to check that stuff??