00camaro ss

we recently bought a 99 1le z28 and when the car is at wot it won't rev past 5k rpm. we thought it maybe was the rev limiter so we used efi live to change it but it was at 6200 rpm. the car pulls hard all the way to 5k. does anyone have any ideas what it could be.

01bad ss

What does the car do a 5k,just stay steady like it is straining or rpm bouncing like on a rev limiter. Does the car have cats?Need more info on what is done to the car,but it sounds like plugged cats to me on on a guess w/o knowing more info on car.

teke184

iTrader: (5)

fuel starvation
pluged cats
slipping trans
slipping clutch
bad coils

you should be getting some kind of SES light i would think

BlackScreaminMachine

iTrader: (17)

Agreed

Check for any codes (scan tool)

Run a Fuel Pressure guage, taped to the windwheild and report the reading under WOT, there should be no pressure drop other then 1-3 psi.

Try those 1st, if all checks out, and depending on how the rpms stop, either they kick down (valve float) or just hang and stop at 5k it maybe a whole different issue. Start with the cheap stuff 1st.

99blancoSS

iTrader: (115)

heres a guess.. massive oil related buildup on the intake side of things.

00camaro ss

it has longtube headers with slp catted y with less than 5k miles on them and its a 6spd. car with 4.10s. its not like its hitting a rev limiter it just holds at 5k rpm. the car only has 30k miles on it. were going to borrow the coils off of another car and try that today. thanks for all the help everyone.

wilddawg

sound like a couple of broke pushrods to me giving you a false limiter. coils will still let the car pull rpms just have a hard time doing it because of the extra fuel being unburnt

Carter01

iTrader: (11)

Most current updates.
1. No fuel pressure issues, pressure is holding with less than 1-3 lbs either way
2. New plugs
3. No issues with wires
4. Swapped out all 8 coils
5. No injector issues
6. Swapped out MAF
7. Uploaded tune from 02 still no change so put orignal tune back in
8. Pulled all pushrods and none bent

Few final thoughts: The car has a SLP underdrive pulley and to the eye it appears to have a little wobble in it. Is it possible that the pulley is going bad and wobbling at high RPMs and creating enough sound that the computer references the sound/noise from the wobble as knock and is pulling timing causing the rev limiter like stutter.
FYI- The car does have a vibration around 1500rpms under normal excel (could be the pulley)
FYI - After datalogging the car several times it is pulling 2-4 degrees of timing when it hits around 52-5300 rpms but you can rev the car past that point and it revs ok to 6k. It just has that terrible rev limiter like stutter around 52-53 and timing is being pulled.
All info is appreciated!

lilbuddy1587

iTrader: (1)

Seafoam in the brake booster line and Seafoam the TB inlet. I'd also check the valve springs.

3rdgentug

iTrader: (23)

if its not getting any power in the upper rpm range i know i ve heard countless stories about 02's going bad doing similar, i dont know from first hand experience but have read quite a few threads that sound similar to yours being O2 related

Carter01

iTrader: (11)

Just wanted to give thanks for all the help on this issue. My good friend finished changing out my 25% underdrive pulley today and putting my stocker back on and it fixed the problem. It appeared that the underdrive pulley was either faulty or damaged at install and caused the issue. I will be adding this to my pool of trouble shooting ideas for future reference if anyone else has this problem.

Thanks again!!!!

Dex

iTrader: (5)

interesting

98Camarod

iTrader: (43)

Thats good to hear that you got it all sorted out.

slowandrichws6

iTrader: (2)

very interesting

toneloc60

iTrader: (7)

glad to hear you're up and running. Enjoy.

99blancoSS

iTrader: (115)

I'd love to see an explanation of how putting a bigger pulley, which ads more strain, fixed the problem.

dlove

iTrader: (23)

he said the old one was wobbling

hopefully it didnt cause any wear on the motor

Carter01

iTrader: (11)

I almost feel as if there is a bit of disbelief in some of the members tone on this post. I can't explain myself any better than what I already have. The pulley must have been faulty in some shape or form. The pulley may have been damaged on the install or maybe a factory issue, I'm not sure but what I do know is that the car responed the exact same way with every trouble shooting method we used (I listed them earlier in the thread) except when we put the factory pulley back on. Wether or not it make perfect sense the pulley fixed the issue and I'm too happy to have my car back on the road. Once again thanks to all those that truly wanted to help diagnose this issue.

NoGamesLS1

iTrader: (16)

Do you have MSD coils? If so I'll put money on that being your problem