Going Lean
Posted: Mon Aug 14, 2017 8:05 am
I've been beating my head against a wall for a couple weeks now. I'm hoping someone here can see something I can't.
The Setup
Installed on a Porsche 914 4-cyl.
MicroSquirt v3 running 3.83b firmware.
LS2 COP running wasted spark.
AEM 30-2310 Wideband Inline
Walbro 80psi,255lph pump set at 32psi.
Fuel pressure monitored via electronic gauge.
VR sensor with 36-1 crank wheel.
No cam sensor.
New 30lb/hr injectors.
The Problem
The engine doesn't rev past 3000 rpm. And in fact, if you start from a stop, it'll accelerate fine up to around 3000, then it'll start to sputter and drop off. Much like a rev-limiter. The WBO2 is reading full lean (20:1), but the fuel pressure is still solid at 32psi. I even tried to push through it and let autotune work it out, but it just kept adding fuel (up to around 130+ on the VE table).
Some Things I've Tried
- Swapped coils with another set: No change.
- Reflashed firmware: No change.
- Rewired ignition circuits to add cap. filtering on 12v supply: No change.
- Increase Req. Fuel arbitrarily in a couple steps: No change.
- Confirmed fuel flow direction, pulled injectors and inspected for plugging (none), checked fuel hoses for kinks (none).
- Resealed intake to avoid vacuum leaks.
- Checked valve adjustment (fine).
- Replaced spark plugs: No change.
Please take a look at the attached log file and let me know if you see something I don't...
The Setup
Installed on a Porsche 914 4-cyl.
MicroSquirt v3 running 3.83b firmware.
LS2 COP running wasted spark.
AEM 30-2310 Wideband Inline
Walbro 80psi,255lph pump set at 32psi.
Fuel pressure monitored via electronic gauge.
VR sensor with 36-1 crank wheel.
No cam sensor.
New 30lb/hr injectors.
The Problem
The engine doesn't rev past 3000 rpm. And in fact, if you start from a stop, it'll accelerate fine up to around 3000, then it'll start to sputter and drop off. Much like a rev-limiter. The WBO2 is reading full lean (20:1), but the fuel pressure is still solid at 32psi. I even tried to push through it and let autotune work it out, but it just kept adding fuel (up to around 130+ on the VE table).
Some Things I've Tried
- Swapped coils with another set: No change.
- Reflashed firmware: No change.
- Rewired ignition circuits to add cap. filtering on 12v supply: No change.
- Increase Req. Fuel arbitrarily in a couple steps: No change.
- Confirmed fuel flow direction, pulled injectors and inspected for plugging (none), checked fuel hoses for kinks (none).
- Resealed intake to avoid vacuum leaks.
- Checked valve adjustment (fine).
- Replaced spark plugs: No change.
Please take a look at the attached log file and let me know if you see something I don't...