Lean AFR on rebuild
#1
Lean AFR on rebuild
Just installed a wideband on my S4 TII with stock boost, injectors and ECU with all emissions removed and it is leaning out as soon as boost hits. In 5th gear doing 55mph I see a 13.9 to 14.1 AFR. Anything higher then 2500rpm brings it into the 15+ range.
So upon checking my fuel pressure regulator, I can't adjust it up past 28 PSI which made me believe that the fuel pump isn't getting enough voltage or the fuel pump is leaking inside the tank. Currently have a Walbro 255 installed in the tank.
I did the rewire but this didn't change my AFR or allow me to turn up the PSI on my FPR. I just want to make sure the way I did this (I am terrible with wiring) deleted the 2-step relay. I would have checked voltage under boost, but I was by myself.
I used this kit
STM FUEL PUMP REWIRE KIT | 1G DSM | 2G DSM | EVO
And I followed this diagram, mostly. Only thing I did different was I went straight from pin 87 on the relay to the cut on the fuel pump blue wire. I did not connect anything from new relay to old resister/relay
Also, I did not cut any of the engine bay harness or stock fuel pump relay/resister. Please let me know if I got it right, and to try changing fuel pumps next. Or any other possible suggestions.
So upon checking my fuel pressure regulator, I can't adjust it up past 28 PSI which made me believe that the fuel pump isn't getting enough voltage or the fuel pump is leaking inside the tank. Currently have a Walbro 255 installed in the tank.
I did the rewire but this didn't change my AFR or allow me to turn up the PSI on my FPR. I just want to make sure the way I did this (I am terrible with wiring) deleted the 2-step relay. I would have checked voltage under boost, but I was by myself.
I used this kit
STM FUEL PUMP REWIRE KIT | 1G DSM | 2G DSM | EVO
And I followed this diagram, mostly. Only thing I did different was I went straight from pin 87 on the relay to the cut on the fuel pump blue wire. I did not connect anything from new relay to old resister/relay
Also, I did not cut any of the engine bay harness or stock fuel pump relay/resister. Please let me know if I got it right, and to try changing fuel pumps next. Or any other possible suggestions.
#5
Moderator
iTrader: (1)
When you pull the fuse and the engine continues to run, I gather you still have the key in the on position? If that's the case, then you need to make sure the relay you installed is wired as in the diagram aside from the fact that you are running the wire from pin 87 directly to the Blue wire of the fuel pump. If you wired things correctly to pin 85 and 86 then there should not be voltage feeding the fuel pump. Are you sure the Blue wire to the pump was cut and connected to pin 87 or did you just splice into this wire from pin 87? And this is important, if you did indeed cut the wire you need to make sure you chose the proper side of the cut wire that you connected to pin 87. When the Blue wire which powers the pump is cut you have one side of the cut wire which runs directly to the pump and the other side of the cut wire runs to the Circuit Opening Relay. In your case you do not want pin 87 connected to the wire which runs back to the Circuit Opening Relay. A continuity test would tell you if you chose the right end of the Blue wire.
Last edited by satch; 05-21-14 at 04:21 PM.
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#8
Solo/Runner
iTrader: (5)
Im not so sure that the streetport is the issue. Double check timing and ohm out your injectors. Inspect the injector o-rings while your at it.
I am running (well was as of two weeks ago) a very large streetport on a stock ecu with just a FCD. My AFR are normal both with the stock S4 Tii Pump and an FD pump. Only difference being when I'm around 8-10psi my AFR are closer to 11.3:1 with the FD may have touched 10 a few times.
Besides that I would suspect fueling. The only issue I have with my streetport on a stock ECU is it will only Idle happy at 1100. I'm sure once I wire the Haltech and injectors, blahblah all will be fine
I am running (well was as of two weeks ago) a very large streetport on a stock ecu with just a FCD. My AFR are normal both with the stock S4 Tii Pump and an FD pump. Only difference being when I'm around 8-10psi my AFR are closer to 11.3:1 with the FD may have touched 10 a few times.
Besides that I would suspect fueling. The only issue I have with my streetport on a stock ECU is it will only Idle happy at 1100. I'm sure once I wire the Haltech and injectors, blahblah all will be fine
#10
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you might also want to put a boost gauge in the FPR vacuum line, not all of the stock nipples see boost AND vacuum. its a really common n00b move to put the FPR vacuum line in the wrong place.
when you get it wrong, the FPR will see vacuum, so the car will run ok, but not boost. a stock T2 will just hesitate and fall on its face
when you get it wrong, the FPR will see vacuum, so the car will run ok, but not boost. a stock T2 will just hesitate and fall on its face
#11
you might also want to put a boost gauge in the FPR vacuum line, not all of the stock nipples see boost AND vacuum. its a really common n00b move to put the FPR vacuum line in the wrong place.
when you get it wrong, the FPR will see vacuum, so the car will run ok, but not boost. a stock T2 will just hesitate and fall on its face
when you get it wrong, the FPR will see vacuum, so the car will run ok, but not boost. a stock T2 will just hesitate and fall on its face
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Jeff20B
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09-16-18 07:16 PM