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missing under load, backfires, popping

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Old 04-22-2011, 04:16 PM
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Originally Posted by budhayes3
This is a strong possibility also, and from what I've seen, faulty/clogged truck injectors are fairly common. I've seen pics of lifters with this rusty looking gunk in them, either completely or partially clogging the injector.
Well, leak down test this weekend and i'll go from there i guess. To get to the injectors will probably need to pull the blower off as they're a real pain to get at on the passenger side with the j-tube in the way. I'll probably send them to FIC to be cleaned/tested. While the blower is off, i guess i might as well pull the heads and check on the lifters too? Assuming that when i pull the valve covers nothing jumps out at me as being damaged or worn.
Old 04-22-2011, 05:37 PM
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Im gonna go with map sensor cause with sd tune thats all the pcm controls the injector flow with. What map sensor are you running?
Old 04-22-2011, 05:53 PM
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Hope ya get it figed out man, ,that sux chasing unknown issues.

Bring it over to Beaver falls, i'll be installing the 80E in my truck Tomorrow morn. and Pat will be there helping, Your welcome to try any of my sensors if ya need to rule out bad ones??
Old 04-23-2011, 07:35 PM
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Originally Posted by Bluchevypick
Im gonna go with map sensor cause with sd tune thats all the pcm controls the injector flow with. What map sensor are you running?
GM 2bar map sensor part # 12615136

If it was bad, my AFR would be jacked and I'd surely be throwing codes, no?
Old 04-23-2011, 07:36 PM
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Originally Posted by TIM Z
Hope ya get it figed out man, ,that sux chasing unknown issues.

Bring it over to Beaver falls, i'll be installing the 80E in my truck Tomorrow morn. and Pat will be there helping, Your welcome to try any of my sensors if ya need to rule out bad ones??
Thanks Tim Z for the offer that sure is nice of you.
Old 04-23-2011, 07:52 PM
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if your pulling heads just change the lifter while you are there i have seen so many issues with the lifters on your truck and the denalis simliar years an newer trucks. just change them with ls7 lifters and ls2 trays your there it only takes a minute and cheep insurance. i have seen lifters fail on that engine but usually it make tikking noise or missfire. it may be sluged up. put a 1l of trans fluid in it runit take it for a quick ride drain oil put new oil in and drive for a week see if it happens. it goes away bingo and change lifters anyway. realy nice ss silverado man.
Old 04-23-2011, 07:53 PM
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Originally Posted by Holty
GM 2bar map sensor part # 12615136

If it was bad, my AFR would be jacked and I'd surely be throwing codes, no?
Not necessarily. You have the older sensor. I have part # 12580698
Old 04-23-2011, 08:57 PM
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Originally Posted by Bluchevypick
Not necessarily. You have the older sensor. I have part # 12580698
Actually, i'm pretty sure 12615136 is newer and replaced 12580698. At least according to gmpartsdirect.com
Old 04-23-2011, 09:03 PM
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Originally Posted by Holty
Actually, i'm pretty sure 12615136 is newer and replaced 12580698. At least according to gmpartsdirect.com
I have had alot of problems with mine lately and i was told that i had the better sensor.
Old 04-24-2011, 03:40 PM
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Originally Posted by spiro27
if your pulling heads just change the lifter while you are there i have seen so many issues with the lifters on your truck and the denalis simliar years an newer trucks. just change them with ls7 lifters and ls2 trays your there it only takes a minute and cheep insurance. i have seen lifters fail on that engine but usually it make tikking noise or missfire. it may be sluged up. put a 1l of trans fluid in it runit take it for a quick ride drain oil put new oil in and drive for a week see if it happens. it goes away bingo and change lifters anyway. realy nice ss silverado man.
have you see issues with lifters causing misfires but the pcm never registers the misfires?


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