thewumpus99
Donating Member
Hi guys,
Got a fueling question. I was driving home on the highway about a month ago, and my wideband AFR pegged lean and stayed there until I got home. Since then, when I start it up, it runs fine for about 30 seconds, and then pegs lean again. If I try to drive it anywhere, it starts doing some serious knocking, so I don't think it's just the gauge misreporting (plus I removed and cleaned both AFR gauges with no change. Computer is a custom program from John Waller who built the truck, burned onto a brand new EEPROM 12 months ago).
I hooked up a fuel pressure tester, and my pressure gauge needle seems to constantly bounce between 30 and 50 (target is around 40). Adjusting it doesn't seem to make any difference in the lean issue.
What's weird is that I tried unplugging a ton of sensors (AFR, O2, even the MAP), and they don't cause any kind of change, it's still pegged lean.
My questions:
1. Could the injector pulses from the 50# injectors causing this bounce on the fuel pressure gauge? Or do I need to replace the fuel pump (it's in the gas tank on these, right?)
2. Any other thoughts on if there's anything else that might cause my truck to suddenly run super lean? Hate to drop the money/time on the pump replacement unless I can conclusively rule all the other 'usual suspects' out.
Got a fueling question. I was driving home on the highway about a month ago, and my wideband AFR pegged lean and stayed there until I got home. Since then, when I start it up, it runs fine for about 30 seconds, and then pegs lean again. If I try to drive it anywhere, it starts doing some serious knocking, so I don't think it's just the gauge misreporting (plus I removed and cleaned both AFR gauges with no change. Computer is a custom program from John Waller who built the truck, burned onto a brand new EEPROM 12 months ago).
I hooked up a fuel pressure tester, and my pressure gauge needle seems to constantly bounce between 30 and 50 (target is around 40). Adjusting it doesn't seem to make any difference in the lean issue.
What's weird is that I tried unplugging a ton of sensors (AFR, O2, even the MAP), and they don't cause any kind of change, it's still pegged lean.
My questions:
1. Could the injector pulses from the 50# injectors causing this bounce on the fuel pressure gauge? Or do I need to replace the fuel pump (it's in the gas tank on these, right?)
2. Any other thoughts on if there's anything else that might cause my truck to suddenly run super lean? Hate to drop the money/time on the pump replacement unless I can conclusively rule all the other 'usual suspects' out.
