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MAF?

This is a discussion on MAF? within the General Help forums, part of the LSx Technical Help Section category; a/f ratio is all over the place from about 13 to way lean. it idles lean at 15-16. it's running ...

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    2001 Silverado

    MAF?

    a/f ratio is all over the place from about 13 to way lean. it idles lean at 15-16. it's running terrible. tries to stall under any load at all. MAF sensor is clean. it has the innovate wide band o2 sensor kit on it and i recalibrated the o2 sensor hoping that would help but nothing. should i try a new MAF sensor?

  2. #2
    Electrical Engineer KMdef9's Avatar
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    Couldn't hurt.

    But was this problem occurring after the install of the wideband and recalibration of the o2's?

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    ls1 powered seabee sutie's Avatar
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    does it read normal when its cold? or is it constantly jumping all over the place from the moment you start?

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    it's had that system on there for a while and i recalibrated the o2 sensor trying to fix the problem. this started yesterday afternoon on my way home from work. from when i fire it up, the a/f is jumping all over the place. i'm going to make sure the MAF is clean again and if that doesn't work, what next? thanks for the help

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    pajeff02's Avatar
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    The air/fuel ratio will bounce up and down -- it is trying to hit a moving target. I also have the LC-1 and what you described does not sound all that unusual to me.

    If a real problem does exist you should check fuel pressure, look for a vacuum leak, and scan the car for codes. You will sometimes see a pending code that has not set the SES light off yet.

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    old timer blue02Z's Avatar
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    Also to rule out the maf you can unplug it while the key is off and then start it. The ecm should go to speed density and if it runs okay then you most likely have a problem with the maf

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    ls1 powered seabee sutie's Avatar
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    ^^ thats a good check, you can also tap the flat part of the maf with a screwdriver or something while the car is running, if the car sputters, are sounds like a miss, your MAF is probably bad. but like stated before, a bad vacume leak( loose or cracked hose) will cause the same symptoms.

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    Moderator 35th-ANV-SS's Avatar
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    Quote Originally Posted by pajeff02 View Post
    The air/fuel ratio will bounce up and down -- it is trying to hit a moving target. I also have the LC-1 and what you described does not sound all that unusual to me.

    If a real problem does exist you should check fuel pressure, look for a vacuum leak, and scan the car for codes. You will sometimes see a pending code that has not set the SES light off yet.
    This. Fuel pressure at the rail should read between 55-60psi.

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    pewter
    2000 b4c ls6 Camaro

    Ok so what signs do you get when a
    Maf is going bad? I have a post about po300-po1133 I've been dealing with.

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    ls1 powered seabee sutie's Avatar
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    you have a random/multiple missfire code, and a heated oxygen sensor insufficient switching bank 1 sensor 1. couple things to check here, your MAF ( which we discussed earlier) bad O2 sensor on 1st bank. also, check your ENG SEN fuse in the engine compartment fuse box. the faulty O2 sensor could have tripped that 20amp fuse, wich will cause a multiple misfire.

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    Moderator 35th-ANV-SS's Avatar
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    Multiple misfire = vacuum leak I bet.

    Post 6 & 7 in here tell you how to check your MAF in a quick n dirty way!

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    2001 Silverado

    a new maf didn't do it. it will run great then all of a sudden it will lean way out and die. after 5min of fkn with it tryin to get it to idle, it'll fire up and run right. if it were a vacuum leak, it would do it all the time and would idle terrible. fuel pressure is good and constant. no check engine light. should have mentioned it has a procharger on it with an edelbrock proflo manifold. thanks

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