Hey everyone, I need some help with this one. My 02 A6 (2.7t w/AT) will not start. I've searched these threads as well as what I could find on the net with no luck. I had an overheat issue but corrected that and the car ran fine afterwards. A few days after it was back on the road there were intermittent periods when it would not start or took an excessive number of attempts. I have since found that there is no power through the fuel pump relay (replaced twice now), I also replaced the fuel pump after jumping the relay and not hearing the pump run. Incidentally the car still will not start with the jumper in place of the relay the car will crank but not fire. I'm not sure if a cam position sensor would inhibit ignition and fuel and that's where I need your help. Thanks Joel

 

Update,
Today I replaced the ignition switch and still have the no start condition. Can anyone point me in the right direction here?
Thanks Joel

 

Before further troubleshooting this issue, is this a no crank no start issue, or a crank no start issue when simply trying to rotate the key?

Have you tried applying 12 volts directly to the starter? Also, what is the voltage of the battery and how old is it? Although voltage isn't the main thing to look for when a no start issue occurs, a low voltage is a good indicator that the battery maybe compromised and not able to provide enough CCAs to turn the starter.

I believe even without power to the fuel pump you would still hear the starter turn, if you're not hearing that then there is something else going on.

 

The car will crank, no problem there. The battery was replaced last summer so it is a little over a year old, and currently the battery shows 11.59v with no decay. The car has been sitting now for over 2 months so voltage is low but I'm not sure if t is low enough to affect starting. I leave for work soon and I will put the battery on the charger and re check it when I get home. I'm pretty much out of my own ideas at this point, I just pulled the front left tire to see if I can locate the crank sensor and check it's condition. I understand the connector is somewhere near the radiator reservoir, maybe I could have done something to it when I pulled the reservoir to clean it when I made the repairs to the cooling system???

 

If it were me, I would first start with the battery and get it checked to determine how many cold cranking amps it is producing. It may not have enough to turn the starter with enough power to start the chemical reactions within the motor.

Your crank position sensor on the 2.7T will be behind (Moving backwards towards the rear of the car) the driver's side turbo pretty much on the bell housing and is held in with 1 8mm bolt (I think 8mm). This isn't a bad component to replace as it's only 30 dollars or so and installation is pretty easy, though I would seriously check the condition of the battery first by taking it to a place with a load tester such as Auto Zone.

 

Thanks for the info, I left the battery on a trickle charge last night and it is up to 12.6v, I am going out to check the crank sensor condition now and if it looks ok I want to try and start, if that is a no go then I will pull the battery and have it tested. Thanks again.

 

Have you scanned the car, is it throwing any codes at all?

When you say "I had an overheat issue but corrected that and the car ran fine afterwards", I'm assuming timing belt replacement water pump/thermostat etc? If yes, did you use the proper tools and preload the tensioner?

Was the battery originally at 11.59v, or did you only check it after repeated cranking? Like suggested by Nebuchadnezzar, pull it and get it tested.

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I'd be interested in seeing what's the coolant temperature reading for your car as it sits. I've seen some weird failures related to the CTS (coolant temp sensor). $10-$12 part unless your car uses the blue one ($40+?). If your car uses the green sensor, they also sell those at advanced auto parts.

 

Yes the voltage is low because of repeated start attempts, I left the battery on a trickle charge for about twelve hours and it now sits at 12.6v.
After the overheat I ordered the timing kit from BlauParts, and replaced the thermostat, water pump, idler pulley, timing and serpentine belts. I followed the instructions enclosed in the kit for compressing the tensior slowly over a 5-10 minute period until I could insert the pin. I used a cam lock tool and prior to removing the timing belt I made index marks on both cam gears and the heads to ensure alignment afterwards. I didn't completely trust the cam lock tool. I did not however have or use the crank lock tool as suggested in the instructions. Once I had the cooling system back together I filled the system with distilled water and checked for leaks, the car began to get hot again and that's when I found the coolant temp sensor and replaced it. The car ran normal with temp in the mid range after wards. I drove it to work the next day (54 miles one way) and had no leaks, all indications appeared normal, no hesitation when accelerating, no rough idle/operation.

Since the car will not start and Auto Zone and Advance scans are at best incomplete I am sad to say that I do not know what any of the potential codes might be. Yes I know without the down load everything I have done to this point was a shot in the dark. I was really hoping that It would have been something straight forward but it sure hasn't.

I do have a CEL that has been illuminated since shortly after I bought the car approx 3 years ago. I don't recall the code but when I had it checked it was for the torque converter anomolly. I was told that it was a common failure of a sensor and have not been able to find anything to determine otherwise. The car shifts and operates normally. The tranny is a sealed unit without even a dipstick so draining and flushing seem to be only a dealer process.

I am at my wits end and since the only European repair shop is over 20 miles away I am looking at renting a U-haul auto transport trailer to take it to the shop for at least a diagnostic and estimate on repair. It will probably turn out to be something simple but my unfamiararity with Audi has left me too frustrated to continue beating my head againt a German brick wall.