E36 318is idle fault.

[MrAlan]

My 1995 318is has a really dodgy idle that tends to idle at 900rpm then randomly revs up and down as it chooses, it pulls away smoothly and works fine otherwise. I did change the icv but it was 2nd hand and barely made a difference, could it still be that or is there anything else that could cause it?
Please help its doing my head in!

[cozmic]

Hi ,erratic idle on e36 318is is a very common problem normally down to either icv, air leak after the maf meter or just general caron and gunk build up.
When i had this problem I remove the air filter cover and with the engine running slowly sprayed carburettor cleaner into the maf unit in short bursts.
I also replaced the rubber boot between the maf meter and the throttle body this can leak even if it looks ok (give the throttle body a spray while youve got the rubber elbow off). Finally check all vacuum pipes and clips especially the ones from the icv. Hope this helps ,oh just out of interest to get 2.1 litre out of a m42 engine you need a spacer plate to raise the capcity ac schnitzer used to do theese but they are very rare/ expensive. The ac schnitzer 2.1 engines produce 180 bhp this was with a tuned chip and big bore throttle body as well though. Supercharging produces similar power output and its an easy diy job
take care Cozmic

[E36-italia]

oh just out of interest to get 2.1 litre out of a m42 engine you need a spacer plate to raise the capcity ac schnitzer used to do theese but they are very rare/ expensive. The ac schnitzer 2.1 engines produce 180 bhp this was with a tuned chip and big bore throttle body as well though.

isn't that just the same as placing thicker head gasket?
still curious idea, got any picture of the spacer, maybe i might reverse engineer it.

i must admit that i have no clue how the gasket of an m42 works... but I do know that this is an old trick with 3,5cc nitro fuelled two stroke engines.


btw: sorry for the off-topic chat

[jscribble]

Just adding a spacer would drop the compression ratio significantly. The only advantage of this would be to tolerate lower octane fuel for forced induction. An engine that does not have any type of boost will likely loose a large amount of power by dropping the compression.

Curious for more info.

[cozmic]

Sorry to drag this off topic a bit the ac schnitzer 2.1 engine as well as employing a spacer block between the head and block also employed a longer stroke crankshaft to maintain a healthy compression ratio, details of this engine can be found quite easily via a search engine on the net google etc

[cozmic]

http://farm3.static.flickr.com/2695/4173689389_33bb09f667_o.png
This is a picture of the hartge version of the spacer plate this punches the cc out to 2.3 litres :eek:
http://img504.imageshack.us/img504/2452/d7443tr2.jpg
This is the hartge 2.1 engine I believe it is very similar to the ac schnitzer engine finding specs on the schnitzer engine is proving more elusive but as and when i find some i,l post them up