Pleas Help!

Post Sat Feb 25, 2006 9:53 am

Had this problem a while now and have tried everything I can think of.
Car ticks over very smooth and nice and quiet (325i cabby) at about 700rpm's(mild zone chip fitted). When I take the oil filler cap off the engine does'nt miss a beat and carries on at same idle and no "gasping". I have checked all pipes and gaskets for leaks, done compression test (12 bar on all 6) had CO2 checked (0.22), changed blue temp sensor and pulled me hair out. I have a k&n cone fitted, but did the same when I changed back to standard airbox.
Can anyone shed any light or think of anything else to try?

many thanks.

Post Sat Feb 25, 2006 10:17 am

sorry if its just me not bein able to see this early, but whats the problem with the car??

Post Sat Feb 25, 2006 10:22 am

gepetto wrote:sorry if its just me not bein able to see this early, but whats the problem with the car??

Agreed - what is the problem ??????

Post Sat Feb 25, 2006 10:22 am

Darren,your post isnt very clear mate

Post Sat Feb 25, 2006 10:23 am

yeah im also confuzzled
have read twice but see no prob

Post Sat Feb 25, 2006 11:02 am

What do you think should happen when you take the oil cap off ?

Post Sat Feb 25, 2006 2:01 pm

i know what he means... when you take the oils filler cap off, the revs should become un steady as engine loses compression, mine does this! soon as u replace cap, engine steadies...

Post Sat Feb 25, 2006 2:11 pm

Yeah but if it doesn't do that there is not nessicarly a problem. The reason the engine goes unsteady when you take the cap off is because air can be sucked in the oil filler cap through the engine and in to the inlet manifold via the oil breather pipe in the TB, thus unmetered air will affect the cars idle and motronic will try to keep the car idling by closing the ICV.
So in theory you may have a blocked oil breather pipe which goes in to the left hand side (front of car) of the throttle body.

Post Sat Feb 25, 2006 4:23 pm

sorry guy's, yeah blingsta got it, I thought that when you removed the oil cap the car should idle erratically. I did mention it when I booked it in for a rolling road yesterday and the guy said I should get it sorted before I take it in. If there was a air leak it would'nt idle smoothly would it. It's had a new breather pipe recently and everything has been carb cleaned. Maybe I'm getting paranoid and used to looking for the next problem.