A4 TDi will not start properly

Posted: Fri Jun 13, 2003 3:03 am

I have just bought an Audi A4 TDi 1996, It runs perfectly, however it will not start properly! If I time it right it will start after the first couple of go's. The glow plug light comes on and goes off in a second (apparantly all A4's are fitted with a quick glow) so this is normal, but car will not start if you try it that quickly. I managed to talk an Audi garage into seeing my car yesterday for a quick check. The engineer immediately said it was the key! (A4's are fitted with an anti-theft device that immobilises the vehicle if the signal from the key is not right) but I said that the other key did the same. He then said it was the actual anti-theft device that was faulty.

Has anyone else experienced this and knows of a fix? Is the mechanic correct? I though all along it could be the ECU itself playing up, I hope I'm wrong

Posted: Fri Jun 13, 2003 9:20 am

There is a known problem with the immobiliser (see the 'NOT MODEL SPECIFIC' forum) - if this is the case then your Immobiliser light will constantly flash - the car will start and then cut out immediately. The immobiliser light should come on for 1-3 seconds when you turn to first stage ignition and then go out if all is fine - if you don't see this maybe the bulb/fuse has gone in which case you obviously won't see the light flash! If the immobilier seems fine then it is obviosusly engine realted. How does it sound when it fails to start? Does the car have problems starting when hot and cold or one or the other? Most likely cause would be glow plugs, then after that temp senders, then injectors (though if it runs fine when started unlikely) - not much to wrong with diesels really...

HTH Smile

Posted: Sat Jun 14, 2003 2:29 am

Thanks for your input on this problem. I made a note when I started my car next, that the immobiliser light does come on for about 3 seconds then goes off permanently with no flashing later. The car however cuts out immediately. This happens when the car is hot or cold. I read in the manual today that the glow plug light should come on for a second when ignition is first turned (which it does) then come on again to show heating of glow plugs, this doesn't happen though even when cold. The engineer ran a diagnostic on the car and found an error with the immobiliser system which he cleared but came back again when he tried to start car. I wonder if the immobiliser is causing the glow plug light not to show up the second time. I hope this won't be an ongoing saga....

Posted: Sat Jun 14, 2003 6:53 pm

I tried to start my TDi with the dashboard out once and got the same problem you have, so check all the plugs are in properly on the back of the dash. Even if the glowplugs arent working at all it should still start instantly this time of year.

Posted: Sun Jun 15, 2003 9:03 pm

I'm starting to make progress on isolating the problem with thanks to the input on this site. Looks like it is something to do with the barrel in the ignition. If you slide the key in smoothly rather than pushing it in as I and most others are used to doing, it starts first time and will continue to start if you then turn it off and on again without removing it. I am still waiting to hear back from another person on the forum who was given the tip of wrapping the aerial wire that apparently runs along the barrel with insulation tape as a fix for this. I have got to replace 2 failed bulbs behind my dash over the next couple of weeks so will check out any connections then. All lights work properly, I checked with an Audi dealership about the immobiliser light staying on for 1-2 seconds, taking longer than the coil light, they said it can take longer, I found it still started with it on any way.