Peterthomas

Hi all,

I recently purchased an '04 B6 1.8t Quattro with the BEX engine. It runs very rough, shuddering and stalling at idle.

I've done the basics:
- new spark plugs and coil packs- Injectors professionally cleaned- checked fuel pressure with gauge (65psi to the fuel rail)- replaced pcv system (damaged hoses, pcv and prv valves)
- charged battery to 14 volts- replaced crank sensor- cleaned all the grounds I could find- replaced fuel pump relay- checked all engine fuses and confirmed they are getting 12v

The below engine codes have persisted throughout my owning the car, I've cleared them multiple times.

The fuel pump relay is getting 12v, and I'm getting 65psi of fuel pressure to the rail. I've tried switching injectors 1 and 2 with 3 and 4, still getting open circuit on 1 and 2. All injectors have around 12ohms of resistance and are getting 12v when cranking the engine. I've also tried a new wire from the injector 2 ecu pin to that injector, and grounding the other side of it to the engine bay, same code persists.

Hoping someone might be able to point me in the right direction with troubleshooting this!

JasoninBRLA

You said the codes were present since owning the car. Was it running rough when you bought the car or is that new?

Peterthomas

Hey Jason, I bought it in this condition - previous owner thought it needed a fuel pump.

grayjay

Fuel injector codes likely due to deteriorated/cracked fuel injector wiring harness, common problem at this age. Numerous repair options for those documented on audizine forums.

Peterthomas

Hi Jay, I've rewired the harness for injector 2 using new terminals and new wire, no joy.

JasoninBRLA

Sorry I can't help. I have always been my weakest at trouble shooting electrical. You have done all the things that I would have tried.

My D connectors were crumbling like many have said for a 20 year old car. Now I found the perfect size heat shrink tubing and heat shrink them. That took care of alot of my electrical issues.

AudiAllTheWay

Try a continuity test from ECU connector pin to your new injector 2 connector. If wire harness is good then the ECU might have defective outputs for injector 1 & 2.

If you have an stethoscope then you can listen to injector body to confirm if they are firing or not.

Peterthomas

Hi guys, thanks for all the replies I've been away for a while and haven't been able to get to the shed!

I can confirm the continuity on all the injector ground wires is 0.05.

Injectors 1 and 2 are definitely not firing, I've got the 4 of them set up to shoot into bottles. They are all getting voltage and if I borrow the ground wire from injector 3 and stick it on injector 2 it will cause that one to fire. So the ECU is not pulsing ground to 1 and 2. I've also tried rewiring the injector 2 ground wire from ECU to injector.

Had a guy come out recently and test the ECU, he couldn't find any issues with it and indicated it should work fine.

Are there any sensors which might shut down the first 2 injectors if it fails, or maybe a ground which might be worth me rewiring?