PCM Diagnostics & Tuning HP Tuners | Holley | Diablo

Breaking up at 5k rpm

Old May 27, 2010 | 04:44 PM
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Default Breaking up at 5k rpm

Ive got a 99 camaro with a ls1 bolt ons, cam etc.. First thing i thought was it was fuel related so i put a fuel pressure gauge on it and fuel pressure goes no less than 55psi at wot and 60 psi at idle.. I checked the knock retard and its at 0 degrees all the way up to 6500 rpm even when its breaking up.. Since the problem occured i have put a new fuel pump, fuel filter and plugs and wires on the car and still no change.. any suggestions would be greatly appreciated..
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Old May 28, 2010 | 08:07 AM
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Valve spring[s]??
Bad ground[s]?
Datalogs?
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Old May 28, 2010 | 12:55 PM
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Default valve springs

valve springs have less than 5000 miles and they are .675 lift
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Old May 28, 2010 | 01:13 PM
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Bent pushrod? Intermittent CPS/CPS cabling issue?
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Old May 28, 2010 | 04:11 PM
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What plugs and what are they gapped at?
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Old May 28, 2010 | 10:17 PM
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Default plugs

Plugs are tr6s gapped at .035 and I had the problem before I changed plugs
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Old May 31, 2010 | 09:29 PM
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I'm having the same problem with mine its dropping out at 5k and my tuner said it is ignition related.At the time when it was getting tuned because i added long tubes and an ls6 intake i installed ngk tr55 plugs gapped at i believe .050.See dyno run below.He said probably a had bad wires so i went ahead and replaced them and i could still feel the power loss.So i fellow tech friend said pull the plugs and look at them so i did and i found cyl#2 i believe did not have a timing mark on the plug.So i went ahead and replaced that coil and brought it back they strapped it down and he said it got better but it was still there just not as much power loss.So i went ahead and replaced all 8 coils after discovering the same problem with timing marks on bank 1 think it was cyl#3,5 but i haven't brought it back to see the difference but i can still feel the stutter at 5k especially when the car is warmed up and its the worst in 3rd gear don't feel it in first or second.So my question is what else could it be its brand new from plug to coil?

[IMG][/IMG]
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Old Jun 1, 2010 | 01:28 PM
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Default coils

That is the exact problem I'm having, its at my tuners shop right now I will let you know if they figure it out
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Old Jun 1, 2010 | 03:44 PM
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Anyone else have any input on the situation?
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Old Jun 2, 2010 | 01:45 PM
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Bump for the day for both of us
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Old Jun 3, 2010 | 05:00 PM
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So no other tuners have input on this?
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Old Jun 7, 2010 | 05:49 PM
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bump for some help
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Old Jun 15, 2010 | 07:49 PM
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Frost anyone?
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Old Jun 15, 2010 | 07:55 PM
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could be related, maybe not, but i had a similar problem. i had an aftermarket underdrive pulley installed (forget which brand) and it started breaking up around 5k or so. put the stock pulley back on and never looked back. no problems since.
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Old Jun 16, 2010 | 02:33 AM
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Valve float...?
Walking reluctor...?
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Old Jun 16, 2010 | 09:19 AM
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Originally Posted by Ls1Rookie
Frost anyone?
There is literally nothing here to go by.
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