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I’m working on a F-150 just had the engine replaced low power or atleast in my opinion. Intake air temp 112 mag g/s 178 rpm 5060. Using the otc calculator online I’m coming with 69-70%. Checked exhaust back pressure it was okay. Front o2 sensors go lean under wot. Checked and cleaned maf also replaced. Checked for intake tube restriction. Also it has a pending code of p2006 intake runner stuck closed. I’m wondering if that could possibly count as an intake restriction?? The guy who put the engine has the wiring harness tangled on the rods so he’s going to re do his work. Hopefully that has an improvement on the test I did. Any recommendations??
You're on the right track with the IMRC. The intake runners not operating properly will definitely cause low VE. Been there, seen it.
Also, give the ATG calculator a try. You're likely to get significantly different readings from OTC.
Unfortunately, the IMRC doesn't explain the low O2's at WOT. Even with the runners stuck, the O2's should still show rich. I think you've got two problems...
He got the intake off again the wiring harness was jammed in the rubber rods. Put it back on seems better than before. Where do I find the ATG calculator vs otc calculator?? I’ll compare the two of them
Reinstalling the intake so the runner actuation rods move freely. :silly: So you fixed the intake on yours, yet the VE is still low... Are the O2's still low at WOT, too?
Yep the guy who installed the engine got the runners to move again. But it’s still low on ve. I looked and it appears to be a dorman maf sensor on it... I’ve checked the air filter for cleanliness. It’s a brand new jasper engine. Desired and actual fuel rail pressure match. O2 sensors still go lean. Either the maf is junk or possibly an injector flow issue. But that wouldn’t explain low numbers on ve
I’m using the launch x431 scanner possibly the scanner isn’t updating quick enough and I’m missing peak numbers on the maf. I might try and borrow a snap on scanner since there graphing is a lot better. And retest.
Cheryl wrote: Either the maf is junk or possibly an injector flow issue. But that wouldn’t explain low numbers on ve
It definitely could, especially being Dorman junk. VE is mostly based on the peak MAF rate. So if the MAF is underreporting, you'll get a lean @ WOT and low VE numbers.
well weve got back on the ford after checking everything today the 2nd new maf sensor reads 140 grams/second at 5016 rpm. so maybe there is an intake restriction. tried driving with no snorkel/filter in it. same thing. checked exhaust back pressure again.
Is that even worse than before? :silly: VE calculator says that's at 54%. No more IMRC faults?
If there's no intake restriction (which you've mostly eliminated), and there's no backpressure issue, then it almost has to be in the engine itself. Used, reman?
VE is mostly based on the peak MAF rate. So if the MAF is underreporting, you'll get a lean @ WOT and low VE numbers.
