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Discussion Starter · #1 ·
Hi all,

Im new on here so... hi everyone!

I have recently bought a 1993 740i, and in the words of Terry Tibbs "its a beautiful car" but, it does have a couple of little problems that Im hoping you guys might be able to help me with?

When it has warmed up its runs really lumpy at idle, and is overfuelling causing it to smoke. it only happens at idle, when moving it clears and drives perfectly.

It also makes a loud squeaking sound. It sounds like a belt slipping, but Im not so sure. This only happens when its warmed up too.

I will be checking the obvious things like o2 sensor and AFM but Im wondering if there any common problems with these? and what else I should be checking..

Also, The squeaking... could this be an air / vacuum leak somewhere? Thus causing the overfuelling as well?

Any help on this would be greatly appreciated..
Thanks in advance..

D:thumbsup
 

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Discussion Starter · #3 ·
Thanks for your help..

After some more investigation yesterday, i found that my squeek stopped when i pulled up the dipstick, so its definitely an air leak somewhere.
Is there supposed to be vaccuum in the sump?
because it was drawing in air when i pulled the dipstick.

Also, I felt around the PCV valve and there was like a small hole under neath it which was sucking in air too. Is that right?

Cheers
D:thumbsup
 

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Discussion Starter · #5 ·
It shouldn't draw air in, all air should travel past the Airflow meter
The hole I mentioned thats drawing air in looks like it is meant to be there though?? (its on the bottom of the pcv and is about 3 - 4mm dia (approx))

I have removed and resealed the PCV and the smoking has stopped. There was an excessive amount of oil in the inlet manifold though, which is quite worrying.. :confused any ideas??

Also, after further investigation into the 'squeakyness', it is coming from underneath and sounds like it is coming from where the block meets the gearbox.

I was told by a guy who had a similar problem with an 840i that there is a pressure valve or something on the sump too?
Is that correct?

cheers for your help..

D:thumbsup
 
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