Rough Idle

[hinchcliffe]

A little troubleshooting help needed. This past winter when it was real cold 10-15 below, my 540i had a real rough idle. Sometimes it would start up then die right out. It would start back up and idle real rough. Also got all sorts of smells: gas, exhaust, coolant. When she warmed up she'd run fine. Check engine light would come and go with a quick rev of the engine. Now that its warm there is no problem.

Now the other day I hosed off the engine then started it up. Ran like crap, making all sorts of noises and smells. Let it sit for a day and she's fine. Water must've dried up.

Now I'm thinking maybe a leaky manifold gaskets, when water got in the motor hiccuped? Sucking in air and water? How do I check without removing it? What else should I look for?

[632 Regal]

sounds like you shoung do the stomp test and go from there. You may have more than one issue going on here, start simple, sensors and such. When was the last time the coils boots injectors and plugs were changed?

[hinchcliffe]

Getting into the plugs and such this weekend, I'm mounting new valve cover gaskets. "shound do the stomp test." Uhhhhhhhh what? Block was replaced at 60k with the Alusil one. Radiator was replaced a few thousand miles ago. Rebuilt tranny mounted in '00. I don't think the plugs were done yet? I just picked the car up in Janurary, sold my '89 535i 5-spd. Is there some sort of smoke test or something to see if the manifold is leaking?

Curt
'95 540i 6-spd
'87 928S4 5-spd

[632 Regal]

stomp test

[hinchcliffe]

When I get the fault codes, where do I find what they mean?

[Bill R.]

smoke generator that you attach to the throttle body and it pumps the intake manifold full of smoke and you can see it escaping from any bad gaskets. I suspect this is where the term blowing smoke up your A** came from There are also ultrasonic headphones and probes that you can get that by moving this probe around the suspected leakage areas you can hear the ultrasonic whistle of a leak... or you can use a small bottle of propane with a hose on it and direct some propane at the base of the manifold where you suspect a leak, if it produces a change in the idle speed then you have a leak, care must be exercised when using propane.. Or some people use a spray can of carb cleaner thats sensor safe and spray around the base of the manifold also listening for a change in the idle speed... Same care when using carb cleaner as any flammable substance.
Or if you have really good hearing take a piece of hose and put one end up to your ear and move the other end around the areas you suspect are leaking with it idling trying to hear a vacum leak...

Getting into the plugs and such this weekend, I'm mounting new valve cover gaskets. "shound do the stomp test." Uhhhhhhhh what? Block was replaced at 60k with the Alusil one. Radiator was replaced a few thousand miles ago. Rebuilt tranny mounted in '00. I don't think the plugs were done yet? I just picked the car up in Janurary, sold my '89 535i 5-spd. Is there some sort of smoke test or something to see if the manifold is leaking?

Curt
'95 540i 6-spd
'87 928S4 5-spd

[winfred]

we had a 94 530 come in that ran like crap when cold and would throw o2 codes, but when warm and reset the codes it was fine, it came down to the intake gaskets were leaking but only during a certain period of warm up, i just happened to catch it with carb cleaner at the right time

[632 Regal]

same place I sent you to, look around the site there. You should also have a Bently manual for your car, a lot of info in them.

[hinchcliffe]

I usually don't keep a car long enough to need the manual for it. I'm on my 28th car since I was sixteen, that makes 2.5 cars per year, and the 928 ain't gonna be sold anytime soon. I checked BMWe34.net before. Thanks for the link, I tried to get to the codes area, but it is no longer available. Anybody out there have a website or list showing the codes? I would really appreciate it. When it first happened I disconnected the battery and all of the fault codes were erased and the car ran fine. Just one of those things, happens when it wants to.

Curt
'95 540i 6-spd 107k miles
'87 928S4 5-spd mileage unknown (motor rebuilt 10k miles ago)
Former owner of: 1989 E30 325ix auto 257k miles, 1991 E30 325ix 5-spd 165k miles, 1990 535i auto 115k miles, and 1989 535i 5-spd 160k miles. That's my BMW experience so far.

[new540iowner]

I've been thinking about that car (or a GTS) for a long time.