PO300 misfire and MAF - please help
Thread Starter
Joined: Jan 2002
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From: Chicago Suburbs
PO300 misfire and MAF - please help OK - major mods F10 cam (228/228 LSA 112) and boltons.
Car runs great, and tuned using hptuners (no wideband)
Pretty much I get PO300 random misfire at low rpms error code, but only when MAF is enabled. When I was tuning in SD mode without MAF, code never popped out. I have the SLP Z06 maf, and I had tables tuned for it....
I also had the low rpms misfire table values "desensitized" I think to 32000
I just don't understand why enabled MAF would cause Po300 ??
Any help would be appreciated....
Thanks
Car runs great, and tuned using hptuners (no wideband)
Pretty much I get PO300 random misfire at low rpms error code, but only when MAF is enabled. When I was tuning in SD mode without MAF, code never popped out. I have the SLP Z06 maf, and I had tables tuned for it....
I also had the low rpms misfire table values "desensitized" I think to 32000
I just don't understand why enabled MAF would cause Po300 ??
Any help would be appreciated....
Thanks
Originally Posted by RedHardSupra
huh? what does disabling maf have to do with misfire detection?
so you're saying that the misfire is real and that misfire detection gets disabled in SD?
Adam, start scanning for individual misfires, let's see if it's real (and is it just bound to a certain cylinder) or it's just sensors being oversensitive
Adam, start scanning for individual misfires, let's see if it's real (and is it just bound to a certain cylinder) or it's just sensors being oversensitive
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Originally Posted by RedHardSupra
so you're saying that the misfire is real and that misfire detection gets disabled in SD?
I knew I had seem my misfire counts ticking away happily in the past (individual counts as well as total). I was surprised when I wanted to trace back my misifre to a cylinder and nothing was counting. Plugging the MAF back in made them start counting. I usually have a handful of misfires on every cylinder (heads/cam) but number 6 was many times what the others were. I unplugged and replugged the wire in and the misfire went away.
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Verdad Gallardo Thread Starter
Joined: Jan 2002
Posts: 740
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From: Chicago Suburbs
Adam, start scanning for individual misfires, let's see if it's real (and is it just bound to a certain cylinder) or it's just sensors being oversensitive
It's not bound to specific cylinder. If it was, I'd suspect bad spark plug wire.... I really have no idea what triggers it....
I'll go over the spark plugs again.... maybe I have two plugs that are not pushed all the way in, hence triggering "random" misfire...random as in "two or more cylinders" ???
you can scan for individual misfire counts on each cylinder.
different things can show up as misfire, for example i had two cars where there was a misfire on 7/8 and it turned out to be just the injector wasn't fully pushed in (not 'clicked'). so the individual misfire counts are really to be used as locators of problems, not something that tells you a definite problem.
with your car, i'd have no idea what it'd be, as it's damn solid and it scans perfect no matter what we throw at it. but a good test nonetheless. the crank sensor relearn would be a good thing, but i'm not sure if HPT put it back in the software yet (they had it in 1.x but pulled it out for 2.x for some unknown reason)
different things can show up as misfire, for example i had two cars where there was a misfire on 7/8 and it turned out to be just the injector wasn't fully pushed in (not 'clicked'). so the individual misfire counts are really to be used as locators of problems, not something that tells you a definite problem.
with your car, i'd have no idea what it'd be, as it's damn solid and it scans perfect no matter what we throw at it. but a good test nonetheless. the crank sensor relearn would be a good thing, but i'm not sure if HPT put it back in the software yet (they had it in 1.x but pulled it out for 2.x for some unknown reason)
