S5 Turbo Fuel Issues

Pete_89T2 · 09-04-2016, 07:57 AM

Hmm, not sure. I'm assuming the car is cranking strong, just not starting, and you checked for any stored CEL codes.

My best guess at this point is it's a wiring harness issue - something is preventing the either the fuel pump from running OR the FIs from firing. Time to crack out the FSM schematic diagrams & go to war.

Couple of ideas to try to troubleshoot further:

1. Try jumping the yellow 2 pin fuel pump test connector. It's located on the passenger side strut tower off of the main ECU harness. With the key in the "run" position, you should hear the pump running constantly when it's jumped.

2. Also with the key in run, check voltages between each FI's "A" terminal pin (per FSM schematic) and ground. All should be reading +12V. If you're not seeing +12V, none of the injectors will fire. If you look at the FSM schematics, you'll see that all of the FI's share a common +12VDC, supplied thru the main relay.

09-04-2016, 07:57 AM	#2
Pete_89T2 Lifetime Rotorhead Join Date: Apr 2010 Location: Elkton, MD Posts: 874 Rep Power: 16	Hmm, not sure. I'm assuming the car is cranking strong, just not starting, and you checked for any stored CEL codes. My best guess at this point is it's a wiring harness issue - something is preventing the either the fuel pump from running OR the FIs from firing. Time to crack out the FSM schematic diagrams & go to war. Couple of ideas to try to troubleshoot further: 1. Try jumping the yellow 2 pin fuel pump test connector. It's located on the passenger side strut tower off of the main ECU harness. With the key in the "run" position, you should hear the pump running constantly when it's jumped. 2. Also with the key in run, check voltages between each FI's "A" terminal pin (per FSM schematic) and ground. All should be reading +12V. If you're not seeing +12V, none of the injectors will fire. If you look at the FSM schematics, you'll see that all of the FI's share a common +12VDC, supplied thru the main relay.