1991 525I Rough Start

[vegasjoe]

Every morning, when I start my car, the engine has a rough start. When I push on the accelerator the rough start goes away. The car runs normally.

There are no error codes showing.

What I what to know is what to search for in this forum for this problem?

[aston_jag_tech]

open ears.....give out all the history of the car, what hwork has been done recently, who has worked on it, miles, and more info on the concern. Very accurate details rock....

[shogun]

Seach for air leaks in intake system. Most common fault.
Start the engine and spray brake cleaner or start pilot all around the air intake system and listen to any change in idle.

[vegasjoe]

I recently bought the car so I do not have the full history.

It has 225,000+ miles on the car. The engine was replaced about 50,000 miles ago. It was a used engine with 90,000 miles.

It chugs like it may be missing a cylinder only at startup. I see no colored smoke coming out of the exhaust.

I replaced the fuel line on the fuel rail. It was leaking fuel especially at startup. But this did not change the rough start.

I replaced the value cover gasket.

I have a small oil leak that I think is coming from the oil pan.

What other information could I gather?

[Morgenster]

Is it just the chugging? Does it take long to get it going (as in does the starter have to crank a long time or more than a second)?
Sometimes bad plugs in a cold engine will do this.
Could just as easily be the ICV not opening fully when cranking.

What i get from the M50 in mine is this:
It cranks for less than a second (a second is long). then as soon as it fires the revs shoot up to 1500 (unles the engine is warm) and quickly drop to idle at about 800 rpm (650 when warm).

If by chugging you mean the engine shakes then some cilinder is misfiring and catching late.

[vegasjoe]

That car starts right away. If I leave it alone it will take about 30 seconds of chugging and then the engine will be at smooth idle.

I do feel that the engine is shaking at the early morning startups.

[Ross]

Maybe an injector leaking down and flooding one cylinder? Any sign of fuel in the crankcase?

[JD525IA]

until I changed the fuel filter. It did feel like one cylinder was not firing for a couple of seconds, and was intermittant. I was suspecting that I had an intake valve sticking.

I know someone thought that maybe you had a leaking fuel injector, but if that was the case, wouldn't the RPM's surge once the fuel ignited?

When was the last time you changed your fuel filter?

JD

[vegasjoe]

I have not changed the fuel filter. I do not know the history on the fuel filter either.

[vegasjoe]

I am not a mechanic but I play one on TV.

Where is the crankcase and how do I check?

[Morgenster]

Great reply :D

If your oil reeks of fuel that's the giveaway.

[Dr. evil]

hydraulic lifers????

[Ross]

AHH, any noises associated with the rough running?