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3 Posts
Discussion Starter · #1 ·
My first post so Hi every one

So I have had the dreaded rough idle for the past 4 weeks, in fact ever since I brought the car....... which was 4 weeks ago!

Car is Euro e36 M3 EVO 64500miles

My problem started about a 20 mins after I picked the car up, as soon as the car got to a standstill it would rock on its suspension, it was so bad that if I hadn't been strapped in and holding the steering wheel I would have been upside down in the passenger seat. So eventually got the car home (this may sound strange but I knew it wasn't the vanos system.... well not all of it at least!)

So spent a few hours/days/weeks looking at the forums and found several things that were of interest.

1. ICV dirty
2. Vanos
3. vanos solenoids seals
4. MAF
5. Vacuum leak

1. ICV Dirty

Well after 6 hours of removing the induction side which was a royal PITB I got to the ICV it was filthy and I mean filthy a good clean and the a couple of hours later it was all back together and the mad rocking on its suspension at idle had disappeared GREAT!..........not really as the thing had the still got a very rough idle but still happy as now I can get the ICV out and back in 2 hours now as I have moved all of the jubilee clip/adjustable cable/hose clamps so I can get access to them with out swearing.

2 Vanos

listened to the engine and thought that it was a little tappety so pulled on the vanos solenoids leads and the and the exhaust connector just came apart in my hands, looked at the locating bracket for the connectors and it was all bent and wouldn't allow you to push the connector home for a good connection, tried to straighten but no good so have had to cable tie connector for the time being....will sort later but now the engine is a lot quieter!

3 Vanos

Read a lot on the forums about solenoid cover bolts and seals so that is what I have done. really quick job and takes about 30 to 40 mins, while removing mine I found that the solenoids have a small pcb with solder joints on, well one of the exhaust solenoids had a dry joint on the pcb so I resoldered it and was pleased to have found something and the engine is now really quiet.........*~#"$ still rough idle!!!!!


Forum says clean maf I did and no difference but notices that with the maf disconnected the engine would work better and run less rough so at least I knew that the maf was doing something.

5 Vacuum leak

OR for me the fuel preparation system....well that’s what real oem call it and that’s good enough for me

I have heard a few people speak about a t-piece that needs a cap at one side but couldn't find this in real oem so just searched for it page by page and found a cap that is located on the fuel preparation system well I needed to take the maf and intake filter of and had a look, sure enough t-piece just behind the hydraulic fluid reservoir I plugged the gap with some fuel pipe and hey presto the Bavarian race car I thought I was buying sprang to life with a smooth idle quiet.

This is just my experience, yours may be different but the car has gone from a head shaking spine jarring hunk of junk to best drive I could ever have hoped for.

Hope this helps anyone in need?

All the best Richard


You try all of the above at your own risk but it has done wonders for my car and me!

PPS this is the link to the fuel preperation system

3 Posts
Discussion Starter · #4 · (Edited)
Ok you may think that I was lucky,

4 weeks and a hundred hours of research not including the 40 hours of removing and cleaning, testing and refitting, it seems the more research, testing, cleaning and refitting that I do the luckier I become....... well if it hadn't taken hundereds of hours of research and 40 hours of cleaning !

My rough idle wasn't caused by the vanos on my e36 m3 evo, the vanos would cause noise, a noise like loose marbles under the bonnet.

I took my time and didn't want to let the rest of my fellow bimmers have the trouble of going over the same things I have.

So luck......well may be a little.....but at least I'm am 100% sure that my vanos wasn't at fault..... though it may have taken less time if I had taken it to BM.

The total cost of the fix for my scary shakey e36 was £43 + 40 hours of labour and countless hours on the net trying to find out why the idle was so lumpy.

But if it helps just one person then the cost is halved.

All the best Richard
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