Pop! 4 second after startup on V8

[Tiger]

Hey,
I got a 540i... it makes a "Pop" sound upon startup... well... 4 seconds after startup. It will only do this after extended shutdown... like first thing in morning... or hours after you come back from work to start it up.

What can it be? Ignition coil in oil?

[epj3]

What kind of pop? Where's it coming from?

[Russell]

Only mine makes a "pop" or couch upon first crank or so on a cold start. If you hold key on it will go ahead and start. Seems as if the sound is near the induction system airfilter area. It seems random.


Hey,
I got a 540i... it makes a "Pop" sound upon startup... well... 4 seconds after startup. It will only do this after extended shutdown... like first thing in morning... or hours after you come back from work to start it up.

What can it be? Ignition coil in oil?

[ryan roopnarine]

it sounds exactly like there's an ignition coil in oil or at least a bad boot in oil. can you smell anything when it does the pop? i'd leave the vents on open and take a smell (inside and out) when it does it.

[Tiger]

In the hood area... I was never there when started...

[ryan roopnarine]

In the hood area... I was never there when started...

you'd do well to get the person driving it to smell, i guess. always gives off a kind of ozone mixed with lit match put to motor oil smell if it is oil on coil.

[632 Regal]

could be a vacume leak or a coil/boot/plug issue. I would do a visual inspection of the electrical end, read the plugs to see if any are a little different. Do a careful inspection of the intake system too. It could be intake gaskets too but Id go electrical first.

[Tiger]

Intake gasket was done by BMW not that long ago...

[632 Regal]

it was done right! start with the plugs and stuff.
Intake gasket was done by BMW not that long ago...

[Russell]

Of course, they could still be leaking. Almost time to change plugs again. This time I was going to check plugs as an indication that coils and connector could be bad. I have has an idication of misfire with ssome fuel dilution issue on used oil analysis.

BTW, several of the previous plugs has a touch of oil. The previous owner never changed the plugs in 76,000 miles. They only followed the SI lights and fix things when they were broke by BMW dealers. The POP is random on my 525i and only on long soak starts.

Thanks


it sounds exactly like there's an ignition coil in oil or at least a bad boot in oil. can you smell anything when it does the pop? i'd leave the vents on open and take a smell (inside and out) when it does it.

[ryan roopnarine]

Of course, they could still be leaking. Almost time to change plugs again. This time I was going to check plugs as an indication that coils and connector could be bad. I have has an idication of misfire with ssome fuel dilution issue on used oil analysis.

BTW, several of the previous plugs has a touch of oil. The previous owner never changed the plugs in 76,000 miles. They only followed the SI lights and fix things when they were broke by BMW dealers. The POP is random on my 525i and only on long soak starts.

Thanks


you should pull one and check the threads. im thinking of putting my boots in a bath of contact cleaner because of oil contamination...my vc is dead.

my car is driven about 1000 miles per week. at that rate, it took about 37,000 miles for the car to start misfiring on the 37k mile plugs. if they were in an american car it would be an unacceptably small spark plug gap, you'd expect to get a good bit more out of them. 29k doesn't sound too unreasonable for them to start going marginal or worse.