Air/fuel gauge working, says I'm running very lean......
09-12-2004, 11:31 AM
#1
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Air/fuel gauge working, says I'm running very lean......
As it should, at idle or moderate gas it's bouncing between lean/rich.
When I go WOT it's showing very lean, WOT is when you get a true reading.
So, what now? Do MTM stage 1+ cars tend to run this way? Any ideas about what I can do to correct it? TIA
When I go WOT it's showing very lean, WOT is when you get a true reading.
So, what now? Do MTM stage 1+ cars tend to run this way? Any ideas about what I can do to correct it? TIA
09-12-2004, 12:20 PM
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I beg to differ
MTM1+ runs 12.5 AFR at WOT as measured on several cars. I do not call 12.5 AFR lean, it might be a little "not rich enough" for CA's craptane for instance, but by no means LEAN.
09-12-2004, 12:23 PM
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Pls check the voltage at the fuel pump
As recently pointed out by some people running RS2 setups, the fuel pump ends up not getting enough voltage (ageing wiring???) so cars run lean at WOT eventually. This is not an MTM 1+ feature as far as I know but a known problem (I've ran across it several times)...
HTH,
Mihnea
PS: if you're getting something stupid like 11v at the pump, simply use the existing wiring to trigger a relay and get direct power supply from the battery. This should solve the problem.
HTH,
Mihnea
PS: if you're getting something stupid like 11v at the pump, simply use the existing wiring to trigger a relay and get direct power supply from the battery. This should solve the problem.
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09-12-2004, 01:55 PM
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Another possibility....
Less likely but still...
If the MAF to turbo hose has a leak in it, false air is going to be sucked into the engine, the MAF will measure much less air going through than what is really going in, thus the ECU will only give fuel for the measured amount of air...
This isn't very likely but still, it's worth it to check this as well, as troubleshooting is never going to cost as much as going through the hassle of replacing an engine in case something melts because of a way too lean mixture...
HTH again,
Mihnea :-)
If the MAF to turbo hose has a leak in it, false air is going to be sucked into the engine, the MAF will measure much less air going through than what is really going in, thus the ECU will only give fuel for the measured amount of air...
This isn't very likely but still, it's worth it to check this as well, as troubleshooting is never going to cost as much as going through the hassle of replacing an engine in case something melts because of a way too lean mixture...
HTH again,
Mihnea :-)
09-12-2004, 04:03 PM
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Boot between the MAF and turbo.....
If unmetered air enters here, the MAF won't read it and therefore you have more air being sucked in than the MAF is calculating fuel for = lean.