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alfistjen · Alfasud Joined: 30 Jul 2003 Posts: 59 Location: Belgium

Hi,

as I have been searching for a solution for that crap dancing idle on my '93 catted 16V I've come across this: I noticed that when the idle is dancing again (sometimes it runs perfect too) that the fuelpump is 'buzzing' louder and quieter on the same rythm of the idle going up and down. Now I was wondering, is it because the engine is asking more-less fuel that the pump has to pump harder or less and that's causing the various buzzing. Or is it the pump itself that is giving more - less fuel causing the engine to run faster - slower? Only something I've been thinking of.
Still I believe I have to kick out the cat and lambda-regulation as fast as possible as I have a engine with non-cat camshafts and I suppose the lambda has a bit of a problem ironing it out on idle.
Any recomendations?

Regards!

Paul D.

robert · Posted: Fri May 21, 2004 1:50 am Post subject:

Hi Paul,

I have a 16V with the same problem (dancing idle). There is no cat or lambda probe, so maybe the cause is something else?

I have not checked the fuel pump during idle, but will do this in the weekend.

Interested to hear if you work out a fix -I had more or less given up.

Regards.

Robert

alfistjen · Alfasud Joined: 30 Jul 2003 Posts: 59 Location: Belgium

Hi Robert,

in your case I'd start looking for false air getting into the manifold as a dancing idle is a typical symptome from this failure. Check everything between the AFM and the intake holes of your engine head for air leaks. What you can do too is taking off the + cable from your battery and attach it somewhere to a earth point (nut from front suspension leg works fine with my car) as that makes the computer reset itself (and the clock, and the radio presets etc.... but that's not a prob) for 15 minutes approx. Like that the computer goes back to its basic setting again. Did work fine on my 1.7 8Vie allways.

Regards!

Paul D.

ady_botos · Posted: Mon May 24, 2004 7:04 am Post subject:

Hi alfistjen,

The fuel pump ussually is noisier when there is little fuel in the tank. I think u should check out first the Lambda probe. Disconect the signal wire (black wire) from the conector, and with the engine runing and warm (85 C) , measure the voltage between the signal wire and ground. The value should change every 1 sec between 0,2 and 0,8 V.