E30 M3 weird noise

Sat Dec 29, 2007 11:12 pm

Hello.
My M3 engine (2,3 02/87) is giving strange noise on low revs (some like ''WRRR WRRR WRRR" - periodically every 0,5 up to 1 second and its look like something is malfunction on one of the cylinders) and I have problems with starting, sometimes it's start in less than 1 sek sometimes I need hold for 5-10 sek to start.

I'm wondering are those problems connected? What can be reasons for those problems (distributor cap, rotor arm, ignition coil, ignition lead, spark plugs)?

If you think video with this sound and starting will help I can provided one.

Thanks for help

Paul

Sat Dec 29, 2007 11:22 pm

I think a video would be best.. initially starting off reading the post, I was going to say "water pump" but thats obviously not the problem.

Post a link to a video and we'll take a look

Sat Dec 29, 2007 11:30 pm

ShepsEvo3 wrote:I was going to say "water pump" but thats obviously not the problem.

Post a link to a video and we'll take a look

Water pump has been replaced while ago. Will post video tomorrow.

Sat Dec 29, 2007 11:31 pm

uhcats wrote:
ShepsEvo3 wrote:I was going to say "water pump" but thats obviously not the problem.

Post a link to a video and we'll take a look
Water pump has been replaced while ago. Will post video tomorrow.

And it wouldnt cause a poor starting problem either. There were a batch of dodgy M3 water pumps out there a while ago, but this was a while ago!

Sun Dec 30, 2007 3:43 pm

Link to youtube with video

http://www.youtube.com/watch?v=m6UdZn_XGRQ

Paul

Sun Dec 30, 2007 3:50 pm

Hmmm looks be an airleak, the "pop" as you return to idle suggests that to me, as does the hunting

check the TB gaskets and around the plenum/intake bellows for splits/leaks, spray carb cleaner in the area with the engine running, if the idle speeds up when you spray there's a good chance you've found the prob.

That said, S14's do like a dizzy cap and rotor too

Thoughts Paul !! ??

Sun Dec 30, 2007 4:08 pm

Ant, I pm'd him back the same.... air leak. I had a similar thing on my evo2, it was the small breather pipe which had split off the top of the sump on the near side of the engine. You need to look at it from under the car, just above the steering rack/column. But also it could be the TB blocks too. Also, that elbow from the AFM to the plenum may well be perished or split... can cause the same simptoms.

That said, I dont think it is the dist cap and rotor arm. Although they do eat them, I think you will have a different type of problem. Half my dist cap was missing on my Evo2 and only had a slight hesitation under WOT in the wet. The center pin and rotor arm were burnt away completely too, but still fired up and ran smoothly in the dry. Crazy engines!!!

Good luck Paul!

Sun Dec 30, 2007 4:21 pm

Take a look here...

http://www.bavarian-board.co.uk/forum_p ... D=29848&KW

I thought the center electrode was burnt out also, but I got confused, the Sport Evo had that and still ran ok.

On the other hand, DarrenM's Evo2 had a loss of power which was down to the Dist cap and rotor arm which looked as new!! See here...

http://www.bavarian-board.co.uk/forum_p ... D=37068&KW

Sorry for directing you guys onto another Forum.

Sun Dec 30, 2007 6:02 pm

Many thanks lads.
Today is to dark to strip it down but tomorrow I'll definitely check it.

Mon Dec 31, 2007 4:56 pm

Hello again.

I took a look today and couldn't locate leak, but I have discovered that adjustable arm of alternator has crank and bottom part of air box has been repaired.
So I need look again or visit some mechanic.

Paul