SSpeed Posted June 3, 2018 Share Posted June 3, 2018 The other night while driving home I heard the fuel pump whining way more than normal, pulled a Learning View and lots of fuel was getting added. 0-<5.60 - 15 5.60 - <10.00 - 5 10 - <40.00 - 15 40.00+ - 2 I got home and pressure tested the intake just in case and found very little. Since my pump was a pre-e85 compatible Aeromotive that I've been using with e85, and it was whining, I figured it was the pump and replaced it with an AEM 320, getting a new unmodified basket in the process. I didn't replace the two green o-rings as I didn't have any and they didn't look swollen or rolled. (Note: I'm going to replace them.) Drove around for about 10min and Learning View seemed to look better, but I was still skeptical so I put in a wideband and had the intake smoke tested. The smoke test showed no leaks. In 3rd the wideband is showing about 12.4 at redline, when it should be 11.4 - 11.8. Learning View is wacky again, almost the exact numbers as my initial problem. 0-<5.60 - 14.70 5.60 - <10.00 - 5.70 10 - <40.00 - 15 40.00+ - 2.10 I'm also getting a small backfire as I press the throttle if I granny shift in super low RPMs. If I set the cruise at 40mph in 3rd it almost feels like it's missing as the o2s jump wildly between 13.9 and 15.0. I've never had a wideband before so I don't know if that's normal behavior? At a static speed and RPM I would assume it would hold 14.7 easier and more consistently? Idle is smooth as butter and WOT power is smooth and strong. You wouldn't know there was a problem if you didn't look at Learning View or the wideband. What should I be looking for? Next steps in my mind are to replace the two green o-rings and check fuel pressure. The low rpm backfire confuses me though. An ignition problem would show up as extra richness vs leanness? If the FPR was going bad I assume it would also pour in too much fuel? The behavior feels like an intake leak, but I've checked everything and the smoke test was clear. I'm stumped. Link to comment Share on other sites More sharing options...
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