530i, _small_ idle problem. Should I worry?

[632 Regal]

you have intake leaks dude, intake manifold gasket leaks including the front and rear intake covers. BMW recommends you drive the car immediately after starting. The shops recommendation of letting it warm swells the leaky gaskets and leaks less.

[newbikekiller]

Hello
I have a 1994 BMW 530i. With the exception of the paint (detailers have been washing it all wrong for a while) it is in excellent condition. I have a complete service record for the vehicle and other than some characteristic problems (like the radiator/waterpump) and some old age problems (leaking trans fluid) there really haven't been any issues.

Recently replaced: O2 sensor, spark plugs, spark plug wires

My problem is that before the car has warmed up, and particularly if I let it idle for >15s before driving it the engine idles a little rough, just enough to barely shake the car. A few times it would set off the check engine at a stop light with the transmission in "D" before it was warmed up, but it no longer throws codes. The car also shakes just a little (even less than when the car is warmed) when waiting at a stoplight with the transmission in "D." I have just been putting it into neutral to avoid this issue.

I tried the "stomp the gas" 5 times thing several times to see the code history to no avail.

Should I worry? Is there any trick to get the code history?

[newbikekiller]

Oh, I should say that the reason the O2 sensor, spark plugs and wires where replaced by the shop was because of poor idle / bad engine performance.

They told me to make sure that the car was fully warmed up before taking off or the engine would throw codes - should I be suspicious of this? I bought the car from this shop, they were using it as a loaner until selling it to me for $5300.

[Tiger]

What wire? There are no spark plug wires for this car.

[genphreak]

you have intake leaks dude, intake manifold gasket leaks including the front and rear intake covers. BMW recommends you drive the car immediately after starting. The shops recommendation of letting it warm swells the leaky gaskets and leaks less.x2. DIY this- and search for how on the forum- and/or find a copy of the Bently manual and the BMW Technical Information System and use that to guide you. :) Nick

[glen-sj]

I usally start the car let it idle no more than 10 sec. before driving off. Have you tried cleaning the Idle Control Valve? Make the valve spin freely within the housing.

The stomp method is to turn the ignition to on (engine on) and press and release the gas padel five times within 5 seconds and count the number of flashes by the 'check engine light'.

[newbikekiller]

I'm a veteran motorcycle mechanic (6+ years) but very new to the world of cars. The most complicated thing I've ever done really were replacing the front brakes on my car (no problem). I'm also an engineer...

Is this something I should rip into myself or ? What is the difficulty level required in replacing these gaskets?

[632 Regal]

Wire boots could be considered wires for a novice. intake leaks AND plugs, wires and boots all contribute to the idle miss. Both V-8s have an imbalance between 1500-2200 rpms, it is a given but smooth up to redlines. Over redline come a major imbalance thus the low rpm redlines coz above the imbalance can cause destruction.


What wire? There are no spark plug wires for this car.