fuel problems while boosting

birdman · 11-04-2002, 08:13 AM

i have been running 8 psi on my 420a for about a week or so and all of the sudden this weekend when i was boosting around 8 the air/fuel gauge dropped into the red. after this i dropped the boost to 7 and it has done it once so far. the fuel system should be good up to about 8psi on stock injectors i am wondering why it would be doing this? anyone suggestions are greatly appreciated. i know i have to upgrade my injectors soon but for right now im just wondering if they could be dirty or something

jw · 11-04-2002, 08:53 AM

I hope you are not using just the A/F gauge for tuning, what does your EGT say?

candela · 11-04-2002, 10:24 AM

Holy nutts!! You rusing stock fuel on that motor for 8psi of boost?? There is no way in hell I would do that, regardless of what you were told. Even in turbo applications, if you run more than 8psi of boost over stock you need fuel upgrades.... What are you using for tuning? If all you have is a crappy autometer a/f gauge or something, you better be planning on rebuilding your motor soon.

birdman · 11-04-2002, 11:00 AM

i have a walbro high pressure fuel pump and the crappy autometer a/fgauge. im gettin my egt next week and bottom end rebuild after christmas.

jw · 11-04-2002, 11:02 AM

I believed the stage 2 kit does come with a FMU for raising fuel pressure.

birdman · 11-04-2002, 11:04 AM

sorry one more thing to add. it runs rich all the time excep every once and when it hit around 8-9psi it will jump to the red then back into the green. i didnt mean it is running lean all the time it happeed 3 times to me total so far so im not sure if it was a problem with the crappy gauge too or what

jw · 11-04-2002, 11:07 AM

You will need more to determine why it cause that to happen. Do you have a logger?

pneumo · 11-04-2002, 11:20 PM

More info. please. Does the motor do anything else odd when the A/F gage goes red? Like a hesitation/ misfire? How long does the gage stay in the red?