WR quattro ECU

[mark c]

I have had a problem with my WR pinging under full boost from time to time. I have changed to Gull 98 and fitted new plugs, distributor cap + rotor and all seemed to be well. Then all of a sudden the pinging starts. I found the pipe that runs from the ECU to the inlet manifold had a kink in it which may have blocked it completely. I straightened out the kink and low and behold the boost gauge works for the first time since I've owned her. Naturally I think I'm on to something. As a further check I detached the line at the inlet manifold and attached a tyre pump. With the engine idling I pumped up the line and the engine revs changed accordingly. OK so I figure that the ECU is changing the timing in response to inlet manifold pressure. Good news. Drive the car for a week and all is well. Feeling pretty smart at this point. Then the next time I jump in it the boost gauge isn't working and it's pinging under full boost again. That was a couple of weeks ago and the gauge hasn't worked since and she's still pinging.

Anyone have any bright ideas?

[portmanteau]

I guess you have seen this info before?:

http://www.isham-research.co.uk/quattro/wiring/Typ85/mac01pin.html

The most common ECU problem so far met is inlet boost pressure sensor failure caused by fuel contamination; this causes poor starting, uneven running and erratic behaviour during acceleration - although even this is rare. The primary cause seems to be the last section of rubber hose before the ECU - after the fuel trap - going porous. It is worthwhile replacing this hose during any test procedure. There is an official test procedure for the pressure sensor - a VAG 1367 is attached to measure the timing point - it should advance from around 6? (before VIN 85-B-901 297) or 12? (85-B-901 297 or after) to over 20? if the hose is pulled off the ECU with the engine idling. Electronic failure is extremely rare - only one case of a cracked PCB board (already the subject of a repair at some time in the past) has so far been seen.

[mark c]

no i haven't seen that. i'll replace the hose completely and see what happens. thanks.

[mark c]

hey thanks for the tip. i've replaced the vacuum line from the inlet manifold right thru to the ECU and the pinging has disappeared and the boost gauge seems to be working. not that it is particularly accurate. i have used the site you have sent me in the past but obviously skimmed over the part that you pointed out. while i was under there i found a few more hoses that looked a bit tatty so i've got a bit more work to do.

[John Stone]

Hi Chris, the quattroforum in the UK is a valuable resource if you are looking for comprehensive info on your car.

John

[portmanteau]

hey thanks for the tip. i've replaced the vacuum line from the inlet manifold right thru to the ECU and the pinging has disappeared and the boost gauge seems to be working. not that it is particularly accurate. i have used the site you have sent me in the past but obviously skimmed over the part that you pointed out. while i was under there i found a few more hoses that looked a bit tatty so i've got a bit more work to do.

you're welcome - glad that I could help

now I have to sort my own over-boost problem!