PCM Diagnostics & Tuning HP Tuners | Holley | Diablo

missfire in detail

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Old Jan 15, 2007 | 05:44 PM
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Default missfire in detail

99 trans am a4: LTs, ORY, !air,!egr. Sd tune.

At the time of my tune my maf was bad so the sd tuned it. All o2s are shut off. I got a miss about two weeks after the tune. Plugs and wires were changed at Lt install maybe 3k mi ago. The miss occurs after the car is warmed up and under light load. Once above 2800rpm it runs like a raped date. So today i checked all fuses, and the 20a eng sens was bad. Replaced it and checked the plugs on driver side. Plugs are fine, as i imagine the plugs on the pass side are. There is spark at all 8 coil packs and all 8 plugs. Car was tuned at Greenlight and yes all o2s are off.
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Old Jan 15, 2007 | 06:48 PM
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im having the same problem with my car , when i try to give it gas my borla exhaust sounds like garbage and the car barely wants to go after 2800 to 3000 rpms did u find your problem yet.. if so plz tell me what it was and i have fire to all coils and my plugs was changed 1 week ago.. thanx
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Old Jan 15, 2007 | 07:23 PM
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no responses yet just subscribe to this one. and this is my 100th post!!!!!!
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Old Jan 15, 2007 | 07:37 PM
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ok plz let me know when u find out
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Old Jan 15, 2007 | 08:05 PM
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The Eng Sens fuse powers (+12V) the 4 O2 sensors and the MAF only. Since you are not using any of those, the fuse being blown had nothing to do with your problem, although it may be why the MAF appeared to be bad at the time of the tune. Since you are apparently running a OLSD tune, you should probably have your tuner recheck everything.
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Old Jan 15, 2007 | 08:09 PM
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damn, that means i prolly just waisted money on a new maf. although the car has 85k on it
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Old Jan 15, 2007 | 08:14 PM
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Why did you buy a new MAF if you have a OLSD tune?
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Old Jan 15, 2007 | 08:24 PM
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cause i want to go back, everyone told me at the time i bought a new maf that if i want to dd i would prefer a maf tune. now after reading with a sd you can tune easier with a big cam i am up in the air
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Old Jan 15, 2007 | 08:32 PM
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The way i look at SD tunes is that in 93 and before, GM used SD, and they havent used it since, so it must not be that great. I'll stick with my MAF tune. Just my .02
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Old Jan 15, 2007 | 08:51 PM
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i agree and disagree except most manufactures can get away without. it helped me rationalize my purchase, also i thought to myself it prolly was bad thats what shorted the fuse out. any more help
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Old Jan 16, 2007 | 12:54 PM
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help for the day??
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Old Jan 16, 2007 | 01:10 PM
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Originally Posted by 2xLS1
you should probably have your tuner recheck everything.
.....
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Old Jan 16, 2007 | 02:17 PM
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trying to get in touch with him, sent him a couple pms i just wish he would send one back
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Old Jan 16, 2007 | 09:51 PM
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working out a day to check it ouy i think its a timing issue
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Old Jan 17, 2007 | 01:15 AM
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ing thisso it may be a computer error or is my tuner gonna tell whats the problem cause
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Old Jan 17, 2007 | 05:23 AM
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Originally Posted by 98 Raptor TA
The way i look at SD tunes is that in 93 and before, GM used SD, and they havent used it since, so it must not be that great. I'll stick with my MAF tune. Just my .02
Sounds like you've done your homework.
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Old Jan 17, 2007 | 12:02 PM
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i like how the maf compensates for things. i would like to turn the front o2s back on but do you think they will be burned up since they have not been registering
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Old Jan 17, 2007 | 12:14 PM
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Originally Posted by dpw41285
i like how the maf compensates for things. i would like to turn the front o2s back on but do you think they will be burned up since they have not been registering
as long as they are plugged in they will be fine...depending on the size of the cam they might not be worth their weight though.
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Old Jan 17, 2007 | 12:16 PM
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Originally Posted by 98 Raptor TA
The way i look at SD tunes is that in 93 and before, GM used SD, and they havent used it since, so it must not be that great. I'll stick with my MAF tune. Just my .02
Tell that to Hundreds of thousands of GM I4/I6 owners with no maf from the factory that it hasnt been used since 93...

Even as late as 05 the I6's were in SD...I think for emissions purposes GM finally switched over to maf in 06 on their I6's.

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Old Jan 17, 2007 | 12:20 PM
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what wont be worth their weight? i just put in a new maf, the cam i will be running will be 235/239 600.600 112lsa is that gonna make tuning with the maf hard?
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