i have a 1995 316i coupe and on start up and for a while after the car idles at slightly above 1000rpm, it drops and down then goes back up to around that level - self reving. the car has done 151k, do you think the erratic idling could be down to the high mileage the cars done or maybe it could be the MAF.
any other suggestions?
s
|
Possibly CVV quite common failure & causes eratic idle.( crank case ventilation valve) Also check for air leaks around manifold.
Doc
One way to diagnose this is to remove oil filler cap & see if there is a slight suction there!, be warned oil will spray out & beware of moving parts
|
|
|
doc
I'd, almost, put money on that diaphragm valve too; P0171 will be along soon.
|
took off the rubber hose from the air box that leads to the engine and everything is ok, and checked for other possible leaks but could not find any.
where is the cvv located and is it a relativly easy job that i can do or is it one for the garage
|
adam
There are a couple of variations in E36 1.6 engines; but if you follow the breather hose from the engine it's the round thing where it connects on to the inlet manifold.
IIRC; one type was on the top and the other was on the back of the manifold; but it's been 6 years since I last saw one, so don't take that as gospel.
How did you check for gasket leaks?
|
|
i only took the pipe off and checked for cracks in the rubber, but tomorrow i will run some fairy liquid round the joints seals.
|
had a web check and found out a way of checking. it said to put a carrier bag over the oil filler cap hole and if it sucks then the crank case is fine, which i done. Is this right?
so if that is right then the crank case it not the problem, any other ideas, still cant find any air leaks
|
you didn't read my original post as I said it shoudn't suck . if it sucks quite well then it means the valve diaghram has gone . You wont find air leaks with fairy liquid iether thats only good for pressure not vacum!, dont spray WD40 around looking for air leak iether as this shortens the life of the lambda sensor. if you cant find the valve leave it too an expert
Doc
|
when you say valve diaghram what do you mean? i never heard of this or is it another word for the crank case you mentioned? (a round flat plastic case with one rubber tube going into it, held on by 2 srews from underneath)
i took the pipe off that leads to the crank case and cleaned out the sludge inside and removed crank case but it does not seem to be cracked.
when i cleaned out the sludge it held its idle a little better but not to much.
|
ok after a little thinking over this problem, do you think its advisable - from waht has been written, that i replace crankcase (if we are on about the same part)
if anyone has other Ideas that could be the problem than please advise.
thank you so far for the responses
|
Yep thats the part & it has a diaphram inside it & they rupture causing air to leak through in basic terms, just replace & try if your confident that you have checked my other suggestions. If you have some one that has a scanner you could check to see if any fault codes present! Fuel trim weak Or lean or lambda sensor fault anything indicating a weak mixture will point to an air leak of some sort & if checks dont find an air leak change the CVV or if your still unsure find a good diagnostic tech. Despite the motor trade being constantly run down there are some very well experienced diagnostic Techs out there who are very knoledgable the only problem is they all get tarred with the same brush & people won't accept there wealth of knowledge. I used to find that friends would listen to the born again mechanic in the pub because it would be a cheaper option than taking my advice & doing a job properly only to find they would end up doing again with proper bits & a good tech.
You keep asking fopr advice when Screwloose & myself have both said the same thing you need to get on with it or find a good tech
Doc
|
Really appreciate both advice and thank you.
will get a new cvv tomorrow, if no joy then i know a mobile mechanic with diagnostic equipment and he will be called.
Edited by Pugugly {P} on 07/10/2007 at 19:44
|
|
