Power dips from 5,000 - 6,000
08-15-2006, 01:47 PM
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Power dips from 5,000 - 6,000 Stock internal 01 LS1 25K miles, 160*thermo, hardened pushrods, full length headers, no cats, borla. underdrive crank pulley, Hypertech tunning, Walbro pump.
Only under load the engine will have a noticable drop / sag in power roughly between 5k - 6k then come on strong untill the rev limiter. I had KR being recorded during this event. I put 100 octane in and no help, I removed the Hypertech and it was better but still there. I secured the exhaust better and I ran power to the fuel pump from the battery and verified 58 psi solid up to the rev limiter. I have cured all the KR, but the drop in power is still there.
Autotap is showing LTFT and STFT are all zeros at wide open throttle. This engine is in a 95 and the intake has an slp ramair hood and airbox that has the maf sensor at a slight downward angle going to the throttle body. The maf has its screen, any help is appreciated. Looking at the o2's it looks like its running pig rich could it just be loading up?
Only under load the engine will have a noticable drop / sag in power roughly between 5k - 6k then come on strong untill the rev limiter. I had KR being recorded during this event. I put 100 octane in and no help, I removed the Hypertech and it was better but still there. I secured the exhaust better and I ran power to the fuel pump from the battery and verified 58 psi solid up to the rev limiter. I have cured all the KR, but the drop in power is still there.
Autotap is showing LTFT and STFT are all zeros at wide open throttle. This engine is in a 95 and the intake has an slp ramair hood and airbox that has the maf sensor at a slight downward angle going to the throttle body. The maf has its screen, any help is appreciated. Looking at the o2's it looks like its running pig rich could it just be loading up?
08-15-2006, 02:42 PM
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your trims aren't used @ WOT, your in open loop mode, ignore them. if youre getting KR I doubt its pig rich at that RPM range where you are having your problem.
I would put it on a dyno and make sure they have a wideband O2 sensor.
I would put it on a dyno and make sure they have a wideband O2 sensor.
08-15-2006, 04:23 PM
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The stock fueling, which Hype-tech may not touch (?)
is piggy from factory. Any fuel fade might be in your
favor.
A history of KR will push you down onto the low octane
timing table and would take some time to unlearn. If you
can scan "knock learn factor" (aka adaptive spark) it
should be 1.000 to use the HO table values (though
these could be bumped most likely with other tune
elements properly set).
You can ignore zeroed trims at WOT but don't ignore
positive LTFTs, they are a cry for help.
Scanning > guessing.
is piggy from factory. Any fuel fade might be in your
favor.
A history of KR will push you down onto the low octane
timing table and would take some time to unlearn. If you
can scan "knock learn factor" (aka adaptive spark) it
should be 1.000 to use the HO table values (though
these could be bumped most likely with other tune
elements properly set).
You can ignore zeroed trims at WOT but don't ignore
positive LTFTs, they are a cry for help.
Scanning > guessing.
08-15-2006, 09:07 PM
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we see a lot of rich cars sag in the hp dept. and will sometimes "blubber" fuel enough to induce KR, believe me you have to take care of the fueling before you can advance in timing. with the mods posted above i would imagine you have a free flowing fresh air intake, and double that with headers and no cats I got a five on it that says says mister cat over temp is your plauge, find someone in your area to give you a basic "TUNE " to deleat some of these problem areas that these wicked little LSx PCM's are known for
Good luck, Brent
Good luck, Brent
08-24-2006, 05:41 PM
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I just bought HP tuners. I have Removed COT, and basic edits.rear O2 delete, CAGS, fans, ect... everything else is stock First question both fans run even before ect is up to prescribed temp. ????
Back to bog problem, I have tomorrow only to get ready for a road course event. I know one header is hitting the frame, which may explain some of the KR, but is the WBO2 fat enough to induce Kr also. Both pulls were made on the street in 2nd gear. Considering I'm way down on the learning curve with HP tuner ( have only had it one day to play with it ) is there anything I can do to cure my bog temporarily without hurting the engine. Thanks for any help in advance.
Back to bog problem, I have tomorrow only to get ready for a road course event. I know one header is hitting the frame, which may explain some of the KR, but is the WBO2 fat enough to induce Kr also. Both pulls were made on the street in 2nd gear. Considering I'm way down on the learning curve with HP tuner ( have only had it one day to play with it ) is there anything I can do to cure my bog temporarily without hurting the engine. Thanks for any help in advance.