Hello fellow Audi enthusiast.
I got an Audi 100 1994 2.6E (Engine code: ABC), i got i very cheap because it wont start. The previous owner had a workshop trying to fix it, and they change the camshaft senser, coilpacks, different relays, and the ignition modul (black thing with 2 connectors). I have then tried to change the engine box, the one in the car was a Hella with the number: 4A0 907 473 A. I changed the box to one with the number: 4A0 907 473 B. When i tried to start the car, it fired once, and then died and now it wont do anything again. The fuel pump relay is clicking, and i can hear the pump when i turn on ignition, but it wont start.

I'm a car mechanic and i have tried everything i could think of, but still nothing, i have now put 12 hours in to it over two days, im really close to giving up and just send the car to the scrapyard, but i wont give up. I really want it running so i can get rid of my crappy Audi 80.

Hope someone can help me with my issue. Sorry for my bad english or wrong mechanic words. Be free to ask me if there is something i have missed!

 

Take the ignition switch out and check it..if you have the "old style" switch it may be cracked..and you car will be hopelessly screwed up and things just don't work. 1994 would be an old switch design.

Pretty easy to do..remove the instrument cluster then a cover on the switch with the lock-out cable and two small flat head screws..use an OEM switch if you need one.




You hear the fuel pump relay clicking..be sure you are getting fuel to the injectors..with great care..remove the inlet fuel line going into the injector rail and direct it into a container...spin the engine over and see if the fuel is filling the container?

If not..fuel pump dead..maybe a fuel filter. Low flow problem.

Button the fuel lines back up and see if you have spark? After any spilled fuel has evaporated. Got spark?

The Audi engine control units are very tough and don't fail very often..I would be inclined to use the one that came in the car for testing. When you install another control unit..you usually need to check the software coding and workshop codes for your exact model Audi..a VCDS is the correct tool to check.Ross-Tech: VCDS-Lite Manual: Coding Without a VCDS..try your original control box.

There is a mass ground of several brown wires on the passenger side of the intake manifold..those are ground for the injectors..be sure they are clean and tight.

Under the passenger footwell..where the engine controller hides..be sure the plug connector for the control unit is in good condition..there is a water leak problem in there if the fire-wall drain becomes plugged up. Water can damage the plug connectors and that plastic bridge that hold the fuses or themo- fuses..remove each fuse and clean them..or replace any suspect fuse or thermo-fuse. Moisture in there can cause weird fuse problems too. One of those fuses/thermo-fuse is for the fuel pump and will cause a low voltage problem to the pump if it is slightly corroded.

See if you can get e buddy with a VCDS local to you to help if the above is without results.

 

I have tried everything you suggested and still nothing, i cant get my hands on a vcds, but is there any other way to check for codes?

 

I don't know if a 1994 euro model has OBD-1...if so you might get codes by testing if your car has a check engine light. See the link: 12v Pages - Maintenance

 

Update, i got a tester with OBD-1. The original ECU in the car is dead, i could communicate with it, but only read the ECU code. Installed the new ECU, changed the ECU code, and now it will start shortly and then die. It only gave me one error code, but i have forgotten the code, and i had no time to get a picture of it because it's pretty late where i am right now. When i googled the code it had something to do with the ECU not working because of the immobilizer. But im pretty sure the car has no immobilizer. Again, thanks for the help!

 

Could be the new control unit is looking for an immobilizer that is not there? Interesting...you may be on track