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Discussion Starter #1
been looking for the leak for a while, decided to try blowing hard itno the intake boot to cause pressure and got my missus to spray wd 40 around. turns out the base of the dipstick tube is leaking air quite badly. will this cause the idle to be crap and the revs to hang when changing gear and loss of low end power?:confused
 

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ok. done that, replaced oring and did the two on the dipstick while i was there. idle seems less laboured and 'quieter'??:confused but thats cool. having done another 'blow test' it still doesnt hold the pressure and i can hear air escaping somewhere under the manifold. should it hold the pressure?
 

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We've gotta see a picture of that - Bet the neighbours were having a chuckle :rofl

But to answer your last question, yes, it should hold pressure. If it's leaking from a hole/crack/badly fitted manifold, then when your engine is running, thats where the air is being taken in.

IIRC you've had the manifold off before, when you put it back, did you make sure both mating surfaces were clean and flat ?
 

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Discussion Starter #6
We've gotta see a picture of that - Bet the neighbours were having a chuckle :rofl

But to answer your last question, yes, it should hold pressure. If it's leaking from a hole/crack/badly fitted manifold, then when your engine is running, thats where the air is being taken in.

IIRC you've had the manifold off before, when you put it back, did you make sure both mating surfaces were clean and flat ?
yeh i bet it was a real laugh!!!:lol they've probably seen me do stranger things than that:jaw-dropping:lol

i thought so, i imagine the pressure even at idle is far greater than my 'blow'?
meaning that me having to go red like a beetroot to make it leak with the dipstick tube sealed would be easy for the engine to do.

all seemed ok with the manifold refit, new gaskets etc. the air leak seems to be more toward the TB side of the manifold tbh
 

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Rough idle will be there due to the air is not all coming through the mass air flow mater at the front and therefore its sucking air in somewhere else and the ecu cant detect this and get mixture right.....You need to find the leak also check the rubber elbow for cracks as they go ,,,the one from the back of air flow meter to trottle housing..
 

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i thought so, i imagine the pressure even at idle is far greater than my 'blow'?
There's no pressure in the manifold at anytime. It's in vacuum at idle, and minimal vacuum at WoT !

Have you tried the carb cleaner ?

If you spray WD40 on an airleak, it'll take it in and burn it in the cylinder, where as with carb cleaner, it can't burn, so the idle will get irratic, possibly cutting out !
 

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Ferret, as far as i know WD40 burns but badly in engines. Revs should drop for a bit with it entering the combustion chamber.
 

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WD40 is flammable.

It contains liquefied petroleum gas, but also has carbon dioxide to reduce it's flammability.

Carb cleaner is non-flammable.
 

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Discussion Starter #12
ok so after some further pipe blowing etc , I have located the air leak, there is loads of air coming out around the cam sensor. so I guess the oring is gone on that too. will that be causing a problem as its not on the manifold?
 

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Discussion Starter #14
changed the seal on the cam sensor and changed the vaccuum hoses. where the vaccum pipe goes into the fuse box to feed the exhaust valve, the rubber poipe joins to a hard plastic pipe, this was all split and cracked up.
done a complete delete of the system, removed vacuum canister and blanked off the hole in the manifold. car idles as smooth as silk!!!:D seems to be a lot smoother in general. well happy:lol
 
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