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M42 failed emissions, high nox, help please
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The numbers shown could be indicative of the engine running lean, which would raise combustion temperatures and thus NOX. A fuel delivery problem or intake leaks could cause that. The first things I'd do would be to smoke test the intake and check rail pressure.The car makes it possible, but the driver makes it happen.
Jim Levie, Huntsville, AL
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Originally posted by jalopi View PostDoes your car run good? If so, then it's probably not running lean. A bad cat can also cause this.The car makes it possible, but the driver makes it happen.
Jim Levie, Huntsville, AL
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Originally posted by jalopi View PostOh, the woes of pre-OBD... is there no such thing as historic or hot rod tags in Georgia? In MD if your car is at least 20 years old, you can get those and not worry about emissions.
But the car runs well, too low of an idle at start up and alot of vibrations then, but once it warm the idle is fine. I read that this is a common problem for m42s, and that to test for vacuum leaks, pull the dipstick out, if RPMs drop, no leaks, if they remain steady, leaks. I did it, and they didnt change, so I'm gonna hunt for leaks.
Also, the PO installed a full magnaflow exhaust system in it, pipes, brand new cat ( so he says, but it does look new ), and muffler. BUT I finally got in contact with him recently and he said the O2 sensor is not installed. That's probably why the CE light is on. Does anyone know where I can source one? I checked pelican but they're all like 190 dollars, and I know I can find cheaper. thanks for the info guys, I have about 9 days to get this car ready for ~100 mile/week commute coming up when school starts, it's almost there!sigpic
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why do you need a code reader when 5 depressions of the gas pedal will flash codes?
PO did not state cel status...?
There are no OBD "woes" The engines not running right. thats all.
This is probably not a cat problem. It seems to me you need try a few things first.
1.Run some seafoam through the intake.
2. Add seafoam to 1/2 tank of fuel
3. Drive it and burn up all that fuel
4. Then change the oil and put in some good new plugs(NGK)
5. Go retest and see where you stand.
Turbo M42 Build Thread :Here
Ig:ryno_pzk
I like the tuna here.
Originally posted by lamboButtchug. The official poster child of r3v.
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Originally posted by Dj Buttchug View Postwhy do you need a code reader when 5 depressions of the gas pedal will flash codes?
PO did not state cel status...?
There are no OBD "woes" The engines not running right. thats all.
This is probably not a cat problem. It seems to me you need try a few things first.
1.Run some seafoam through the intake.
2. Add seafoam to 1/2 tank of fuel
3. Drive it and burn up all that fuel
4. Then change the oil and put in some good new plugs(NGK)
5. Go retest and see where you stand.
"PO did not state cel status...?" what?sigpic
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Originally posted by z6ne View PostI've only ever had an m20, this is my 2nd e30, so I don't know a lot of specifics about m42. Plus I'm working with my dad on it so he wants to be very thorough.
"PO did not state cel status...?" what?
The rules are kind of the same for all engines. What I meant was you never stated you had a check engine light or not. Do you? my bad on the typo.
Turbo M42 Build Thread :Here
Ig:ryno_pzk
I like the tuna here.
Originally posted by lamboButtchug. The official poster child of r3v.
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Originally posted by Dj Buttchug View PostThe rules are kind of the same for all engines. What I meant was you never stated you had a check engine light or not. Do you? my bad on the typo.
Would the light be on because of a lack of o2 sensor? I feel like that might be it, but in that case the light would've been on since I purchased it.
How much do these things go for used?sigpic
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