LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

lacking power at WOT

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Old Jun 11, 2007 | 08:20 AM
  #1  
ZL1modified's Avatar
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lacking power at WOT

My car pulles alot harder when i am ~1/4" from WOT...

i have no check lights on...

Does anyone know what could cause this.


fyi: i am running stock injectors, ngk tr55's @ .050 gap, stock maf, new opti, a/f pressure regulator and 8.5 msd wires...
Old Jun 11, 2007 | 08:37 AM
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Im no expert, but i think the computer goes into certain loop (open/closed?) at WOT. sounds like a tuning issue to me for that reason. I would suggest 02 sensors but I would think youd have the problem at partial throttle if that were the case.
Old Jun 11, 2007 | 10:50 AM
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i might add that it always takes two tries to get it to start...

^ you don't think the computer would throw a code?
Old Jun 11, 2007 | 11:13 AM
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I would do a fuel pressure test and see what it is doing at WOT.
Old Jun 11, 2007 | 11:41 AM
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I thought the O2's weren't used at WOT? I could be wrong though. Do you have any knock retard at wot? Is your exhaust hitting the frame at wot?
Old Jun 11, 2007 | 12:02 PM
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If your fp looks ok at WOT, then I'd suspect either 1 of 2 things:
O2 has gotten lazy causing your BLMs to be at one extreme or the other... the O2 play a part at WOT in that the computer will add whatever percentage of fuel to the existing PE/WOT fueling depending on what the BLM's were when you went into WOT/PE (power enrichment mode).
IF your BLM was below 128 when entering PE, then the computer will end up adding some fuel in PE mode as it will lock the BLM to 128..thus causing it to run a bit richer than before it entered PEmode because it was cutting some fuel before PE mode (lower than 128 BLM).
IF the BLM was above 128 when entering PE mode, then the computer will continue to add a little additional fuel on top of the PE fueling..the higher above 128 the more fuel it will add....thus maybe causing you to run too rich which would explain your problem.

Or..the computers PE mode fueling is way off causing you to run rich and it needs to be reprogrammed....this is where a wibeband O2 is very valuable.

Or make that 3 things...may be getting knock at WOT causing it to pull some degrees of timing....need a scanner for this determination.

Last edited by 2QUIK6; Jun 11, 2007 at 12:06 PM.
Old Jun 11, 2007 | 02:37 PM
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sounds like some good direction...

thanks all
Old Jun 11, 2007 | 02:45 PM
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sounds like what my car is doing it has alot more power at 1/2-3/4 throttle and i know im running rich cause you can smell it when my car is at idle
Old Jun 11, 2007 | 02:57 PM
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I have put posts in before on this very thing. It is better now that i have replaced the 02's and added headers. Not sure if this was the problem.
Old Jun 11, 2007 | 03:04 PM
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im adding headers here soon but i also want to do a tune hopefully that will fix my problem.
Old Jun 11, 2007 | 03:11 PM
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i already have headers and my o2's have about 3k on them... my car has been running rich since i got it... but you can definently tell the difference between 3/4 throttle and wot... it actually puts you back in the seat at 3/4 throttle and wot hesitates a little and doesn't pull as hard as 3/4...
Old Jun 11, 2007 | 03:12 PM
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yea my cars O2's have like 4k on them cause i just had to replace both of them and my car is still running like that lol maybe the Headers/Tune will help me out
Old Jun 11, 2007 | 03:28 PM
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are your headers coated and if so did you install them? coated headers need to be properly heat cycled when installed BEFORE you put the new 02 sensors in or else the fumes from the coating will ruin them. I heat cycled mine at least 6 times and drove the car twice without 02s before I put my new sensors in.
Old Jun 11, 2007 | 03:29 PM
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the headers i bought from a friend already used so they shouldnt need to be heat cycled
Old Jun 11, 2007 | 03:33 PM
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Originally Posted by Executioner2k5
the headers i bought from a friend already used so they shouldnt need to be heat cycled
i was referring to the thread maker, but in your case yea they shouldnt have needed it.



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