QuestionI have an '88 convertible, 325i, 127,000 miles. Car is in good condition. Last day or two, I've had difficulty starting the car - never happened before. When I turn the key, the engine turns over and fires up, but runs/idles rough. I have to really pat/baby the accelerator quickly and the rpm's slowly build up, and after 5 - 10 seconds it runs/idles fine. No problem at highway speed, and no problem if I turn the engine off and crank back up within a short period of time. But if the car sits for 30 minutes or so, same problem. I thought I had some trash/water in the tank, put in a fuel system cleaner, but no change.
I recently had a minor problem with the driver's side door lock and unhooked the battery for a while during repairs. Wonder if that had anything to do with it?
AnswerLeon,
Sorry for the late reply, I was sick over the weekend.
This is one of those nagging little problems that have no strait forward answer. Trial and error will be the only way to find it out. It sounds to me like the plugs may have oil/carbon build up on them and they need to be cleaned/replaced. I would get the car up to temperature and drive it hard. I dont mean "beat" on the car, but rev the engine up and make it work. Take to an on-ramp of a freeway and press the throttle to 75%, make the engine rev to 4-5k rpm before shifting. This is known as an "Italian Tune-up". Most times people take it easy in these cars and allow them to build up "gunk" in the engine. By taking the RPMs up to 4500-5000 ever once in a while will help to prevent this, as it blows any soot out of the engine. I think if you did this it would help. I own an 87' convertible, and drive it daily. I make sure to "work" the car a couple times a week. Like when I'm getting on the freeway on my commute, I'll open it up and let the engine breathe a little. It doesn't hurt anything, your letting the engine do what it was designed for. That being said, I also dont drive the car like that for extended periods. make sure to give these engines plenty of warm-up time as well before driving them hard. And after driving hard give them a little cool-down period. driving hard on a cold engine is like and athlete jumping out of bed and strait onto a treadmill... he's not going to perform at his best!
If you do the "italian Tune-up, and still notice a problem, try giving the car a REAL tune-up if it hasn't been done in the last couple years. A "real" tune-up includes, spark plugs, spark plug wires, distributor cap and rotor button, and a coil. If any of these have not been replaced in the last couple years, its probably time.
If that doesn't solve the problem, then try cleaning the idle control valve. It's a small cylinder located on the intake boot. Its simple to remove, and spray it out with some carb/choke cleaner.
Hope this helps,
Josh
