Working on a S5 with all emission deletes performed. The car starts up everytime but after 5 seconds the engine light comes on and fuel pump is turned off and car dies. Only way i knew it was the fuel pump was when i jumped the fuel pump the car stayed on and running. So has anyone experienced this before and have any idea what could be the cause.

 

I thought the fuel pump would shut off if the AFM does not provide a signal to the ECU. 5 seconds before cutoff rings a bell.

 

Are you referring to the MAF? If so i have 3 of them and used them all and same results.

 

Are you getting any codes?

 

I have tried but got nothing. Nothing happens when i do the jump.

 

When did this problem crop up? Out of the blue? Or after some fiddling?

There aren't too many things that cause fuel cut.

 

My wife rebuilt the engine for this car. Threw in rebuilt engine and now this. "When fuel pump JUMPED" the car idles and everything. But as soon as i remove that jump it shuts down.

 

Are the diagnostic wires actually connected to the ECU? Are you testing 12v at the single green connector with key ON?

 

I must have not been doing it right or wire not grounded right. It's throwing codes now. Going to see what it is and see if it will help.

 

Engine codes 12, 13, 18. Don't comprehend how any of those would effect the fuel pump. 2 of them are tps related but the tps is in spec. And car idles perfect when the fuel pump wire is jumped.

 

If you're lucky your boost sensor and TPS are both unplugged.

Can you verify that they are plugged in?

 

Yeah the tps i know for sure is. But boost sensor could have unplugged. The connection for that is puny.

 

Yeah the tps i know for sure is. But boost sensor could have unplugged. The connection for that is puny. But plugged.

 

I think I understand that yes they're plugged in.

Check connections at the ECU. Check for continuity of associated wires from end to end.