Sorry in advance.. I've chased everything I can at this point so here I am. bought the truck in January and no noticeable issues. A few weeks ago (after it had been running for ~2 hours from errands), I get a slight backfire, then it has no power and won't move. I shut it off and fired it back up and it was good for another ~10 minutes, then it did the same thing, ran like ass and could barely move. Whole vehicle shook, etc. Parked it and attempted to restart and no success. eventually had to tow it home, where it started after the tow. I let it be overnight, and it fired up again in the morning. I swapped fuel filter as a hail mary and strapped a fuel gauge to it. ~35psi. It made it about 45 minutes to a friend's place where it gave out entirely and would not start.
Took several seconds to start after cranking.
When it WOULD run, it would have 20-40psi, but it would vary.
When I would turn they key on, the gauge would make it to 30psi, a relay would click in the underhood panel and pressure would drop off.
Pressing the accelerator, pressure would fall off to ~20psi.
Pressure did not change when I removed the vac line from intake to regulator.
Replaced fuel filter, regulator, no change in pressure.
swapped a delphi pump assembly and had 55psi initially, but still took a while to start after cranking. Noticed down on power under WOT, checked fuel pressure and a steady 35psi at idle but same dropoff at 30psi when I turn the key on but do not crank. hits 30, relay clicks, pressure falls off. I replaced the filter again, no change. weak pressure at the rail.
Swapped in an AC Delco (2 weeks later) and still only 35psi at the rail but it seems to run much better. is there anything I'm missing? no CEL, but pulling codes previously showed each bank is lean. no misfires.
Is my gauge broken? could be be fuel pump wiring?
*EDIT* I failed to point out/didn't invest enough time into thinking about the fact that the regulator I swapped was a used one from my silverado I had gone to aftermarket rails (apparently factory regulator couldn't handle 210lb injecors?), so it was used, but worked fine a few years back.. I think? Bought a new AC Delco from Rock auto, tossed it on and away went the issue. I appreciate the guidance/support/sanity checks y'all gave.
Took several seconds to start after cranking.
When it WOULD run, it would have 20-40psi, but it would vary.
When I would turn they key on, the gauge would make it to 30psi, a relay would click in the underhood panel and pressure would drop off.
Pressing the accelerator, pressure would fall off to ~20psi.
Pressure did not change when I removed the vac line from intake to regulator.
Replaced fuel filter, regulator, no change in pressure.
swapped a delphi pump assembly and had 55psi initially, but still took a while to start after cranking. Noticed down on power under WOT, checked fuel pressure and a steady 35psi at idle but same dropoff at 30psi when I turn the key on but do not crank. hits 30, relay clicks, pressure falls off. I replaced the filter again, no change. weak pressure at the rail.
Swapped in an AC Delco (2 weeks later) and still only 35psi at the rail but it seems to run much better. is there anything I'm missing? no CEL, but pulling codes previously showed each bank is lean. no misfires.
Is my gauge broken? could be be fuel pump wiring?
*EDIT* I failed to point out/didn't invest enough time into thinking about the fact that the regulator I swapped was a used one from my silverado I had gone to aftermarket rails (apparently factory regulator couldn't handle 210lb injecors?), so it was used, but worked fine a few years back.. I think? Bought a new AC Delco from Rock auto, tossed it on and away went the issue. I appreciate the guidance/support/sanity checks y'all gave.
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