Jfitzg38

S13 redtop sr20 in s13 chassis.

Wiring specialties pro harness.

Stock setup.

The problem:
-idles perfect.
-Can creep RPM all the way up to redline, but under heavy acceleration/boost it sputters/ falls on its face. Won't hit more than 1 pound of boost. If that.

What I've tried:
New OEM o2 sensor
New coolant temp sensor
Replaced/tested TPS
Replaced/timed CAS
New fuel filter
Cleaned fuel tank
New fuel pump (first one burned out, second was defective, this one seems fine) walbro 255
New fuel lines
New injector O rings (top and bottom)
new FPR
Boost leak test
Smoke test
12v direct relay to fuel pump
Checked coilpacks/ switched with known working ones
Replaced igniter chip
New plugs (gapped)
Wastegate is attached
New AEM uego wideband
No major exhaust leaks
Grounds tested and secured
Replaced ECU with known working one
Replaced MAF 3 times with no result
Wiring specialties PRO harness
Mechanical timing is set




Car was bogging out end of last season, found to be clogged fuel filter. Changed that and this season have had this issue continually after.

Once car reaches boost OR under heavy acceleration will sputter/fall on its face.
AFR reads 15-17 on idle.
AFR reads 17+ after heavy acceleration/boost.
Dropping to ~30 psi fuel pressure under heavy throttle/ boost.
Vacuum is at ~11 LBS which it always has been when car ran great
- My next step is to see if the amount of fuel coming OUT of the FPR remains constant when when heavy acceleration is applied. If so I know that the pump isn't supplying enough fuel somehow.

-^^second step after the above (if all checks out) is to replace injectors.

Last step is to drop this thing off at a shop. I lost a whole season of driving due to a constant troubleshooting/replacement game.



Any input is appreciated!