RE: MAC11 help needed

[John Lagnese]

Knock sensor correctly torqued? They crush easily. Is ther a vacuum leak,
like a hose not connected?

-----Original Message-----
From: quattro-bounces at audifans.com [mailto:quattro-bounces at audifans.com] On
Behalf Of Rick Houck
Sent: Sunday, August 31, 2008 7:00 PM
To: Quattro List
Subject: MAC11 help needed

patient is coupe quattro conversion (dedicated track car) with 10v turbo 
(MC1 w/one knock sensor) motor. I can get the car started and running up to 
2000 to 2500 RPM before it starts backfiring. Can hardly get up to 3000 RPM 
even with throttle floored. The flywheel "0" mark, the cam mark, and the 
distributor mark all line up properly. If I move the distributor off the 
mark (advance) while running, it will rev like normal, but won't start after

shutdown. I can move the distributor back to initial position and it starts 
right up.

I suspect that something is causing the timing to retard, but I have swapped

out the ECU, complete distributor, the cap and rotor, plugs, wires, RPM and 
flywheel sensors. I plan to try another knock sensor, but can't figure 
anything else that would cause a properly running engine to start backfiring

like this. BTW, after the problem, I took the opportunity to install my 
newly rebuilt engine, and the problems are the same, so I can rule out 
mechanical issues.

I have been using the 034 Motorsport EFI, and there is no sign that it is 
going lean or rich when this occurs. My fuel pressure (aftermarket FPR) 
rises slightly as revs come up as I would expect with the start of boost. 
Besides, the timing seems to be the thing that has changed, as evidenced by 
the regular running after advancing timing.

It acts as though the timing reference pin is in the wrong place, but it has

been running fine for 8 years and the problem came on gradually during some 
rainy sessions at Watkins Glen in May. Thought something must have gotten 
wet, but after swapping everything I can think of, nothing has changed.

The pin is still on the front side of the flywheel, but it does not line up 
with the pickup when the crank is at "0" and the distributor and cam marks 
line up. Is this right?

Any help appreciated,
Rick
Pulling my (gray) hair out! 

_______________________________________________
quattro mailing list
quattro at audifans.com
http://www.audifans.com/mailman/listinfo/quattro
---
Watch this space for ads :)

_______________________________________
No viruses found in this incoming message
Scanned by iolo AntiVirus 1.5.3.5
http://www.iolo.com


_______________________________________
No viruses found in this outgoing message
Scanned by iolo AntiVirus 1.5.3.5
http://www.iolo.com