Audi 90 20v quattro Sport

Tun · 03-11-11, 09:55 AM

Hello after months of looking I have managed to obtain a 90 quattro. I have bought it as a non-runner. Using U281 code reader I have obtained the following codes 00514 crank position sensor G4 and 00525 O2 sensor voltage low G39. I think I have located the crank sensor although there appears to be 2 sensors side by side and they have clearly been interfered with. As for the second code I don't even know where to look! Can the sensors be checked without removal? any help would be greatly appreciated. I will post some pictures of the car later.

mikes2 · 03-11-11, 04:16 PM

lambda probe (O2) sits either in the downpipe if you have a tubular manifold or in the catalyst if you have a cast manifold.

It won't affect the car starting.

Crank sensor code is normal on a non start condition

Tun · 21-11-11, 04:25 PM

Starter motor is off the car now and I can see that the crank sensor pin is missing. Is it possible to weld a new one in place whilst still on the car or should it be drilled out and replaced? I have tried to upload picture but have been unsuccessful

.

mikes2 · 21-11-11, 06:58 PM

I've not tried drilling it out - that would be engineering shop job.

I'd recommend trying to get another flywheel

Tun · 22-11-11, 12:44 PM

Managed to tap the broken pin back into the fly wheel with small hammer and punch leaving a 4mm deep recess, then knocked in a replacement pin made from a Ø4mm welding rod into the recess. Re-fitted the starter motor and it started first turn of the key

. Next job though will be to remove the gearbox and inspect the clutch has I suspect that something has dropped of it causing the pin to be sheared off in the first place. But on the bright side at least I know the engine runs

mikes2 · 22-11-11, 05:13 PM

Check the two sump bolts inside the bellhousing are still there.

Tun · 25-11-11, 09:49 AM

Reason for missing crank sensor pin. Clutch pressure plate has given up to of the three spring steel strips have failed, one has snapped off completely and presumably bounced round the bell housing taking the crank sensor pin with it

New clutch should be here today

Andy Douglas · 25-11-11, 12:32 PM

Now you know the cause of the problem!! best of luck getting the car sorted, then ENJOY!!!!

03-11-11, 04:16 PM	#2
mikes2 4 ring whore! Classic Audi Club Member Join Date: Nov 2007 Location: Polmont Posts: 2,617	lambda probe (O2) sits either in the downpipe if you have a tubular manifold or in the catalyst if you have a cast manifold. It won't affect the car starting. Crank sensor code is normal on a non start condition __________________ 1991 90 quattro 20v sport 1991 90 quattro

21-11-11, 04:25 PM	#3
Tun Grown up member Classic Audi Club Member Join Date: May 2011 Location: Buxton Posts: 745	Starter motor is off the car now and I can see that the crank sensor pin is missing. Is it possible to weld a new one in place whilst still on the car or should it be drilled out and replaced? I have tried to upload picture but have been unsuccessful.

21-11-11, 06:58 PM	#4
mikes2 4 ring whore! Classic Audi Club Member Join Date: Nov 2007 Location: Polmont Posts: 2,617	I've not tried drilling it out - that would be engineering shop job. I'd recommend trying to get another flywheel __________________ 1991 90 quattro 20v sport 1991 90 quattro

22-11-11, 12:44 PM	#5
Tun Grown up member Classic Audi Club Member Join Date: May 2011 Location: Buxton Posts: 745	Update it's alive! Managed to tap the broken pin back into the fly wheel with small hammer and punch leaving a 4mm deep recess, then knocked in a replacement pin made from a Ø4mm welding rod into the recess. Re-fitted the starter motor and it started first turn of the key. Next job though will be to remove the gearbox and inspect the clutch has I suspect that something has dropped of it causing the pin to be sheared off in the first place. But on the bright side at least I know the engine runs

22-11-11, 05:13 PM	#6
mikes2 4 ring whore! Classic Audi Club Member Join Date: Nov 2007 Location: Polmont Posts: 2,617	Check the two sump bolts inside the bellhousing are still there. __________________ 1991 90 quattro 20v sport 1991 90 quattro

25-11-11, 09:49 AM	#7
Tun Grown up member Classic Audi Club Member Join Date: May 2011 Location: Buxton Posts: 745	Reason for missing crank sensor pin. Clutch pressure plate has given up to of the three spring steel strips have failed, one has snapped off completely and presumably bounced round the bell housing taking the crank sensor pin with it New clutch should be here today

25-11-11, 12:32 PM	#8
Andy Douglas Grown up member Classic Audi Club Member Join Date: Feb 2010 Location: St Andrews Posts: 446	Now you know the cause of the problem!! best of luck getting the car sorted, then ENJOY!!!! __________________ No Audi at Present MGF VVC Honda CRV (daily wife bus) Peugeot Expert (work van) VW Polo 1.9 TDI No 1 sons 1st VAG car