A4 won't start

Hi, I would really appreciate some help with a problem I'm having with my 1996 A4 2.6. The car will not start from cold. There is no spark and no smell of
fuel. The imobiliser light goes off as expected. If the car is towed it will start, run smoothly and restart imediately. The car will then drive fine and start normally for the rest of the day. There is no missing or rough idling, the car sounds and drives lovely. If the car is left overnight it will not start the following morning. I have had the codes chacked which, first time, showed a crankshaft sensor error and the second time showed a cam shaft sensor error. Both sensors have been replaced but the fault persists. (This is getting expensive!) One symptom I noticed over the couple of weeks prior to the no-start situation was that the car would require a few turns before starting. Has anyone had this problem or have any ideas what could be wrong?
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Battery?
/Carsten
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My V6 2.4 underwent a similar symptom, failed to start a few odd mornings in particular after cold nights. I checked out the battery with the hygrometer and it showed one cell low. Fitted new battery and all is now well.
I think at the cost of a battery say 70 its your next best try. Keep the old one though don't let the dealer dispose of it....yet.
dj
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Lez Pawl wrote:

I've already tried a replacement known good battery. The car turns over at normal speed but just doesn't fire. The car only requires a slow push to bump start. The only sign of a problem is that it then requires slightly longer turning over to start, but will start for hours afterwards.
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GarryA4 wrote:

Possibly a failing crank position sensor or cam position sensor is out of adjustment. I would pull the codes to see what the computer thinks as a starting place.
TonyJ '98.5 A4 1.8TQM
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ign switch??

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dave AKA vwdoc1 wrote:

Crank and can sensors have already been changed. Garage are changing ignition switch tomorrow. I'm not sure it fits the symtoms of an ignition switch fault. The imobiliser light goes out as expected when the key is inserted. Any more help would be greately appreciated!!!
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GarryA4 wrote:

Well, the ignition switch didn't cure the problem. This fault has a lot of people baffled, but someone must have seen this before.
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Well lets see so far I read that: Cranks but doesn't start. Cam and Crank Sensors changed but faults still pop up. No Fuel & no Spark while cranking. New Battery. hmmmm but it will start by push starting and a new ign. switch did not solve this issue.
I would temporarily try a remote starter switch to see if it starts without fully turning the ign switch to the 'crank' position. Maybe it is the motion of the vehicle while either push starting it or by towing it. Maybe this movement causes a ground connection to work better. Check the ground connections at the body, engine, and wherever else.
later, dave (One out of many daves)

Well, the ignition switch didn't cure the problem. This fault has a lot of people baffled, but someone must have seen this before.
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