Audi a3 2006 2.0tdi wont start after replacing genuine crank sensor

[rwh1000]

We had an occasional starting problem with ou 2.0tdi.
Threw up the code on a snap on solus about a crank sensor fault.....so out came the box and off with the flywheel. Replaced with an ANdrew page crank sensor...After building back up itwouldnt start at all.
Gave us a new code p0341 camshaft position sensor (G40): implausible signal.
So we removed the cambelt (locked it with pins) and replaced cam sensor with an andrew page cam sensor......still wont fire up. Checked the timimg (its spot on).
We decided to take the gear box out again and fit a genuine crank sensor....Still wont fire.
We decided to remove the cams sensor and fit a genuine one....still wont fire. We checked the timing again!
Still got the g40 code so everything points to timing! But its ok!
It runs and sounds great on spray.
We decided to take the box out and replace the oil seal and magnet the crank sensor reads. Still nothing.
Got an auto electrician with out to it. He told us it is reading the crank sensor and cam sensor fine and suggested we check the timing....we did, again! Its fine.
We got my friends identical a3 in and played with this...it fires up with the cam sensor plugged out anyway so we're eliminating that. We took the pipes of his high pressure pump and noticed it wasnt behaving the same as our broken a3 so we got a high pressure pump (from a breaker but tested) its still the same.
It sounds low on compression, so you may assume we bent a valve when put the timing belt back on....but remember, the problem was there before we even touched the timing belt.

Anyone got any ideas because we are screwed now!!!

[Alan02]

Can I ask what timing tool you used? Reason is I had a Sykes timing set which had 2 crank locking tools in and the arrow for TDC on the tool is a tooth out!! Worth googling the the timing tool and comparing the marks on the ones you used.

[robin_bga]

We had an occasional starting problem with ou 2.0tdi.
Threw up the code on a snap on solus about a crank sensor fault.....so out came the box and off with the flywheel. Replaced with an ANdrew page crank sensor...After building back up itwouldnt start at all.
Gave us a new code p0341 camshaft position sensor (G40): implausible signal.
So we removed the cambelt (locked it with pins) and replaced cam sensor with an andrew page cam sensor......still wont fire up. Checked the timimg (its spot on).
We decided to take the gear box out again and fit a genuine crank sensor....Still wont fire.
We decided to remove the cams sensor and fit a genuine one....still wont fire. We checked the timing again!
Still got the g40 code so everything points to timing! But its ok!
It runs and sounds great on spray.
We decided to take the box out and replace the oil seal and magnet the crank sensor reads. Still nothing.
Got an auto electrician with out to it. He told us it is reading the crank sensor and cam sensor fine and suggested we check the timing....we did, again! Its fine.
We got my friends identical a3 in and played with this...it fires up with the cam sensor plugged out anyway so we're eliminating that. We took the pipes of his high pressure pump and noticed it wasnt behaving the same as our broken a3 so we got a high pressure pump (from a breaker but tested) its still the same.
It sounds low on compression, so you may assume we bent a valve when put the timing belt back on....but remember, the problem was there before we even touched the timing belt.

Anyone got any ideas because we are screwed now!!!

Hi, I suggest doing a compression test.
However I personally have a feeling that if it's saying crank sensor & can sensor then double check the connections n that includes doing a continuity test of the wire harness plus looking at the arrangement of the old sensor in comparison to the new one, I mean the way the sockets plug into each other.
Hope that helps.
Cheers

VW Bora V5, AGZ, 99, 5speed Manual Tranny.

[rwh1000]

Thanks for the reply. Not sure what tool off the top of my head. Will check later. However I have used it 30+ times with no problem.
Also it wouldn't explain why it wouldn't start after replacing the crank sensor - before we'd even touched the timing?

[rwh1000]

Thanks Robin
Although it sounds low on compression when cranking, if I run it on spray it runs fine so I assume it's not a valve issue?
The readings are telling us that the crank and cam sensors are doing what they should so I don't think its a plug or wiring issue. The wires are quite simple to see it all looks fine.

[Crasher]

When you fitted the new crank oil seal, did you use the alignment jig? It may be that you have cured the initial fault and introduced a new one.

[rwh1000]

No!
That has to be it. We didn't realise you had to time it as its just a magnet. Do i need the Jig or can is there a work around (drill bits!)

[Crasher]

The alignment has to be extremely precise and I don't know of a way around it. The tool is expensive and so what we have done is in conjunction with a friend who is also a VW specialist, we bought the one for the big engines and we bought the one for the smaller engines and we borrow each others as is necessary. The alignment procedure in the manual is incredibly complex so as to ensure absolute accuracy.

This is a suitable non genuine version of the tool http://www.lasertools.co.uk/item.asp...1080&item=4772 , the genuine VW version is even more expensive.