Car keeps shutting off - p2635 Fuel Pump "A" Low Flow/Performance

[Benihana]

Hey guys, just started getting this code yesterday p2635 Fuel Pump "A" Low Flow/Performance yesterday and the car keeps shutting off (4 times in a 45 minute drive). Recently installed a rs3 brushless with black controller. Car still runs when it's fine but then it will shut off out of nowhere. If you restart the car instantly I can drive for another 20 minutes before it happens again. Any ideas? I was running this setup fine for about a month and everything was running fine until yesterday. Currently on the 4th revision of an e30 tune from Matt at EQT.

Vortex XL
Autotech HPFP
RS3 brushless pump with black controller
e30 fuel

Thanks guys!

 

[EpicTech]

bad controller ?

 

[Diggs24]

Did it coincide with version 4? Did you try version 3? What does Matt say?

 

[EpicTech]

Pulled straight from tech manual, this is also reason I said bad controller.

What does OBD-II fault code P2635 mean?
OBD-II Code Decreased engine performance is defined as a Fuel Pump "A" Low Flow/Performance
The Fuel Pump Control Module determines the required amount of fuel pressure to keep the engine running efficiently. It then commands the fuel pump to operate accordingly to maintain the required fuel pressure. If the Fuel Pump Module sees that the actual fuel pressure does not meet the commanded fuel pressure, code P2635 will set.

EDIT: There is a SLIGHT chance the current tune didnt flash correctly and there is a bad memory address assigned where the fuel controller info is supposed to be, but odds on that are slim. You said it happened with this new black controller, so I think its the controller.

 

[Benihana]

Pulled straight from tech manual, this is also reason I said bad controller.

What does OBD-II fault code P2635 mean?
OBD-II Code Decreased engine performance is defined as a Fuel Pump "A" Low Flow/Performance
The Fuel Pump Control Module determines the required amount of fuel pressure to keep the engine running efficiently. It then commands the fuel pump to operate accordingly to maintain the required fuel pressure. If the Fuel Pump Module sees that the actual fuel pressure does not meet the commanded fuel pressure, code P2635 will set.

EDIT: There is a SLIGHT chance the current tune didnt flash correctly and there is a bad memory address assigned where the fuel controller info is supposed to be, but odds on that are slim. You said it happened with this new black controller, so I think its the controller.

Thanks for the info Epic! Right after I posted this thread I started troubleshooting and I think I might have found the problem.... one of the 3 wires that goes to the fuel pump (yellow wire that terminates at the fuel pumps 4-pin plug) was discolored/oxidized at the black controller end. The copper wire end that was crimped to the connector butt on the controller were all fused into a few oxidized strands. I cut off the burnt area of the wire and added some new wire and plug terminal then patched it all up, cleared all the codes and went for a test drive for about an hour and the code never came back and the car stopped bucking and shutting off. Luckily my controller didn't crap out....hope i'm not jinxing myself!

The car lives another day!

 

[EpicTech]

Yes wiring can definitely cause that, I wasn't thinking wiring issue because I had OEM wiring on the brain.

 

[Diggs24]

RS3 shouldn't be needing that much current that it is melting wires.

 

[EpicTech]

Youtuber JR14 had this problem, except it was just a Walbro 525 setup. Melted all the wires from controller to the pump.

 

[Benihana]

RS3 shouldn't be needing that much current that it is melting wires.

My controller didn't have the best of airflow...while the controller wasn't in the factory location, it was routed to behind the backseat but since the wire length is so short some of it was still slightly sticking under the 60/40 split section which might have caused it to heat up more than usual. I just removed/gutted the backseats so now the controller is sitting out in the open exposed to the ambient air.

 

[Diggs24]

What does the pump duty look like during a pull?

 

[Benihana]

The duty never went above 60% on this pull, this is the latest log I sent to Matt to work on the next revision/

 

[Diggs24]

Yeah, that looks good then. Whose RS3 pump is this?

 

[Benihana]

The pump is the 1st iteration of A2B's pump when they were selling it as a kit with the silver controller.

 

[Benihana]

well this didn't age well...the car started bucking again and the check engine light came back "fuel pump 'A' low performance". Gonna buy a new controller and see what happens .

 

[Benihana]

Hey guys,

I recently bought a new black controller and used that and I had thought it fixed the issue but a week later the problems came back. So I tackled it again yesterday and did the following:

• I dislodged the fuel pump and reseated the rubber O-ring and this time I tightened the snap ring further. I’m thinking the last time I might not have tightened it hard enough because this time it didn’t take much to remove the ring as it did to put it back on fully.

• Also, I was piggybacking my fuel-it ethanol sensor off the fuel pump fuse and now removed it for testing.

• Added a second ground point for the harness.

Gonna test it again after doing the above, but also running out of options at this point. Not sure where to look next, either the wiring harness or fuel pump, or both. My wiring harness is 1st gen A2B and doesn't look as beefy as the harness EQT sells, also the fuel pump is the first gen A2B where the inlet is using the outer edge opening vs. the middle like EQT's iteration. I included the pic the harness for reference.