Help!! Urgent Idle Problem

[BMW328]

Hi

Just after some advice, several months ago my car seemed to idle high and after investigation we oiled the throttle connection and it fixed the problem. At the same time we also cleaned the ICV and the car ran fine sitting at 700 rpm.

Yesterday on my regular route home the car started playing up. It seemed to judder while stopped (even though the idle was still sitting constant). Today on my way to work I noticed the idle high again and stopped in the car park the idle now climbs to 4000rpm and stays there constant. I have reoiled all the throttle connections but this has not fixed it! I presume it will not be safe to drive home? (although when in drive it sits at 1100rpm)

Anyone any ideas? The car is a 1996 P reg 328i Coupe Auto

Thanks for any info.

[zlac109]

i assume given your registration you are un the UK. Have you checked your idle valve? All my friends that have BMWs including me have had to replace that stupid valve at some point coz of this kind of either very high idle or unstable idle with some surge in the injection and the revs going up and down constantly.

If you are in London i can point you to some good mechanics that are not too expensive. Do not wannna do that in a BMW garage you will be paying a fortune or if you are handy it's not very difficult to do a bit of DIY

[97alpineM3]

There is a write up in the DIY forum... for ICV cleaning.. try that... tends to fix most idel problems...

Good Luck,

Les

[2ndclasscitizen]

With idle issues first thing i'd do is clean out the ICV but you said you done that out not long ago, but thats not to say its not faulty itself. Anther simple thing I can think of would be to check round the throttle body (and a general look at hoses) for any leaks where air could get in. I had a hole on the rubber between the MAF and T/B which caused me some problems. The only other thing would be getting the car hooked up to the diagnostic equipment where they will be able to check the sensors which is something you cant do by eye.
I had a major idle issue, wasnt caused by the hole letting air in as I knew the hole was there for a while, but I cleaned out the ICV, gave it a service and its (touch wood) 99.999% better.

[BMW328]

Ok,

Problem now fixed! Was a combination of the sensor that sits in the manifold (think it was an O2 sensor), a split pipe to the vacuum unit under this (only a very fine split that wasnt noticeable until it was removed) and the actual vacuum unit! (it had snapped of its mounting and was loose underneath the manifold)

[2ndclasscitizen]

How did you manage to find the problem, did you get it hooked up to the diagnostic software?

[BMW328]

I found it by process of elimination. Started removing the sensors to clean then noticed the one under the manifold had a damaged tip so decided to replace it. When doing this noticed that the vacuum pump had broken from its plastic mountings so while I was getting the sensor I ordered a new pump as it was quite cheap and at the same time thought Id get new hose for it as its only rubber hose. When we went to change it thats when we noticed the pipe had a split in it!

(Also there wasnt much left to check after that anyway! (had checked throttle cable, idle valve, throttle, all airboxes and relevant pipes, intake manifold)

All back together and working fine now