-4% fuel trims won't trigger the CEL; besides, that means it's in a rich condition, not lean, taking away fuel. We'd all have CELs if that was the case.
Help needed with P0171 & P0174 running lean at idle. My fault!
- Thread starter Kapitein
- Start date
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Kapitein
Full Access Member
I disconnected the battery for 5 mins to reset the LTFTs. They almost immediately run up to +24.55% on idle (the max). But drop to completely normal values the moment you give it throttle.
I also did the water test on both banks for the inlet manifold gaskets. Zero rpm change and zero steam out of the exhaust, engine continued to run the same. So as far as I can tell that rules out my intake gaskets as the problem.
Seems like its a big vacuum leak on the intake side of things, but where
I also did the water test on both banks for the inlet manifold gaskets. Zero rpm change and zero steam out of the exhaust, engine continued to run the same. So as far as I can tell that rules out my intake gaskets as the problem.
Seems like its a big vacuum leak on the intake side of things, but where
OP
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Kapitein
Full Access Member
Sorry thats a typo. It was +4%. But indeed +/- 10% is considered normal and wont set a CEL.
I presume now having enabled some more PIDs on my scanner that its the LTFTs being pegged at +25% thats causing the CEL.
George B
¯\_(ツ)_/¯
Make sure you didn’t knock the intake tube loose from the throttle body.
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Kapitein
Full Access Member
That's all been checked and double checked. Zero leaks on the intake tube.
George B
¯\_(ツ)_/¯
Yeah, sorry I needed to go back and read. This is truly a perplexing problem.
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Kapitein
Full Access Member
Just thinking out loud now... If the oil pressure sensor wasn't tightened down quite tight enough, could that cause a vacuum leak?
George B
¯\_(ツ)_/¯
It would cause an oil leak.
Some scanners will allow you to reset the LTFTs; that would be something to try. I'm wondering if disconnecting the battery for a few minutes and touching the cable ends together, or turning on the lights to drain any residual power, would reset them.
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Kapitein
Full Access Member
I managed to reset the LTFTs by disconnecting the battery.
On closed loop they rise to 25% (max) at idle quite quickly. On the road/under throttle they immediately lower to normal levels.
