High fuel pressure. Need some help.

[watty]

I am having a problem with my 1uz. I had my fan pulley bearing lock up about a month ago and snap the serpentine belt. It seemed fine while I drove home on the battery. The car sat for a while and when i went to drive it, it was running rich and started to cut out like the spark was being blown out. The afr's went from 14.5 to 13.5 at idle and 9.5 at wide open throttle.

The engine is in a 1997 Nissan 240sx running on Megasquirt. I have swapped out computers and checked every sensor.

I checked the fuel pressure. It is reading 58psi on the high side before the dampner and I'm getting 15-18psi on the return line after the regulator. I'm curious what the pressure should be on the return line if any at all.

I'm at my wits end. I have checked everything I can think of. The only thing I can come up with is high fuel pressure is flooding the engine.


Any help would be greatly appreciated.

Thanks
Watty

 

[cribbj]

Hmmm, IMO you've already identified the problem. You shouldn't have any pressure on the return line at all. 58psi minus 15psi is 43 psi, which is exactly the Toyota spec, so the FPR is regulating correctly, but you've got a restriction on the return somewhere. Maybe a collapsed hose or something similar downstream of your FPR.

If you can't find anything obvious, I would take the return line off at the FPR, and at the tank, and blow it out with compressed air. Maybe there is some rust or other particles partially blocking it. I don't know much about Nissan's systems, but I would think they would use something relatively noncorrosive for their hard lines?