Car redlining very early
02-10-2019, 07:09 PM
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Car redlining very early
I have a 92 Camaro z28 heritage edition with a l98 engine 4spd automatic. The car has 323 gears in the rear. When I’m in overdrive (4th gear) my car can’t do more than 70mph without going past the redline. I took the car to a transmission shop and they said when they hooked up the computer everything is fine with the transmission and a few weeks before that I had new gears put in the rear so everything should be good there. I can tell the tac isn’t off because when I get up past 70 towards 80-90 and let off the gas I can feel the back pressure from the engine. Just looking to see if anyone could help me identify the cause of why I can’t go over 100 without feeling like the engine is going to blow.
02-10-2019, 07:27 PM
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Car: Yes
Engine: Usually
Transmission: Sometimes
Axle/Gears: Behind me somewhere
Re: Car redlining very early
I'm guessing this is all from looking at the factory "tach"?
Those fail by reading high. ALL OF THEM. I have one that reads 3 times the actual RPMs, and others report failures even higher than that. Hit the Electronics forum on this site for many discussions.
I'd suggest starting out by comparing the "tach" (wavy pointer "sporty" trim package thing in the dash that isn't really an "instrument") against some sort of known accurate test equipment.
Most likely, your TPI is doing what it does best: protecting your motor from ever seeing any kind of RPM-related stress.
Odds are however, you'll need some form of speedo recalibration as a result of changing the rear gears. I'm going to go out on another limb and make another wild-a$$ guess: you went from 2.73 to 3.23 gears, no?
Those fail by reading high. ALL OF THEM. I have one that reads 3 times the actual RPMs, and others report failures even higher than that. Hit the Electronics forum on this site for many discussions.
I'd suggest starting out by comparing the "tach" (wavy pointer "sporty" trim package thing in the dash that isn't really an "instrument") against some sort of known accurate test equipment.
Most likely, your TPI is doing what it does best: protecting your motor from ever seeing any kind of RPM-related stress.
Odds are however, you'll need some form of speedo recalibration as a result of changing the rear gears. I'm going to go out on another limb and make another wild-a$$ guess: you went from 2.73 to 3.23 gears, no?
02-10-2019, 08:19 PM
#3
Re: Car redlining very early
Just looking to see if anyone could help me identify the cause of why I can’t go over 100 without feeling like the engine is going to blow.
....so is it really reving that high, or is it just the tach?
02-11-2019, 08:07 PM
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Car: Yes
Engine: Usually
Transmission: Sometimes
Axle/Gears: Behind me somewhere
Re: Car redlining very early
What did the test eqpt say the revs REALLY are? Like: dash says xxx; test eqpt says yyy?
02-12-2019, 07:30 AM
#6
Re: Car redlining very early
Yeah, I'm with Sofa at this point....really need to know FOR SURE what the engine is doing. ....and if it IS revving high....like you say, then I don't see how it's NOT the transmission. You said they hooked up the transmission at the tranny shop? Can they test the clutch packs without a test drive? Sounds like maybe a slipping or going bad 3-4 clutch pack? I'm no auto trans expert though....
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