A4 not starting [Archive] - Audi Forums

: A4 not starting

03-28-2012, 09:59 AM
Well here we go,
My sons a4 2001 2.0 litre 20valve ALT engine snapped the cam chain and stripped a few teeth off the cogs, also stripped a few ribs off the cam belt unbellieveably no damage to the valves or piston crowns.
After a long search found two secondhand cams, absolutely crazy prices from Audi and the car not worth spending that kind of dosh on it. Fitted them along with chain tensioner, new cambelt kit etc. I am 100% sure that the setup is spot on but the car won't start, turns over fine tries to fire a little but won't start up. What I would like to know is if there are any known issues with immobilizer reset,engine management, whatever that could cause this. I do seem to be getting petrol and also a spark so maybe a faulty sensor. I am considering unplugging all sensors and try to start as from what I have read the ECM will substitute default settings. Any info appreciated.

03-29-2012, 04:36 PM
Hi guy

I guess you should check your timing especially since you replace the cams. Follow the guideline in the Bentley service manual, check the lobes positions on the cams intake and exhaust they should set very precisely as where they are suppose to be, otherwise your engine would never start.

Before you open the engine up again. Do the compression test. Take the plugs out disconnect the electric to fuel injections check the compression on each cylinder by cranking the engine equal amount of times for each cylinder make sure the throttle body is open (just press on the gas peddle when cracking the engine) record pressure of each cylinder and write it down, if all pressures are the same within 15% of each other your timing is okay, if 30% of 40% of each other open up the head check the valves. . This is an easy way to determine if all the valves are doing there job and your timing is set correctly.

Good luck