'84 Z28 L69 H.O loss of power at high rpm
12-17-2015, 11:12 PM
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Car: 1984 Camaro z28
Engine: L69 5.0L H.O
Transmission: Automatic
'84 Z28 L69 H.O loss of power at high rpm
Hello, I am very new to the site and have had a little problem with my car ever since I got it a year ago. Alot of times when I punch on the gas while already moving, the engine would revv really high, but wouldn't accelerate untill I let off the gas a tad then it shifts up into gear and gets moving. The main thing is when I punch on the gas, it sounds like my engines gonna blow up haha. Ive been told it may be a vacuum leak but may it be something with the tranny? That would be hard to believe because I was told the transmission was rebuilt when I bought the car. Any comments or suggestions would help, thanks!
12-18-2015, 12:51 AM
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Car: 1988 Camaro
Engine: 355, 10.34:1, 249/252 @.050", IK200
Transmission: TH-400, 3500 stall 9.5" converter
Axle/Gears: Ford 9", detroit locker, 3.89 gears
Re: '84 Z28 L69 H.O loss of power at high rpm
TV (throttle valve) cable could need adjusting. Its the cable that runs from trans to your carb. Everybody likes to call them kickdown or detent cables but they are not, not on a 700r4
12-18-2015, 12:11 PM
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Car: 1984 Camaro z28
Engine: L69 5.0L H.O
Transmission: Automatic
Re: '84 Z28 L69 H.O loss of power at high rpm
Thanks, is this relatively cheap to get done perhaps at a carb shop?
12-18-2015, 12:14 PM
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Car: 1984 Camaro z28
Engine: L69 5.0L H.O
Transmission: Automatic
12-19-2015, 07:29 AM
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Car: 87 IROC Z
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Re: '84 Z28 L69 H.O loss of power at high rpm
This post explains how to do the adjustment. It's not hard but it has to be done correctly.
https://www.thirdgen.org/forums/tran...djustment.html
https://www.thirdgen.org/forums/tran...djustment.html
12-19-2015, 09:55 AM
#6
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Re: '84 Z28 L69 H.O loss of power at high rpm
Do the TV cable adjustment, but if it's not that, here's your next two likely suspects:
1. Clogged fuel filter. Nobody every changes them because nobody knows where they are (except us die-hard 3rd genners). It's in the nose of the carb behind where the fuel line attaches to it. If you've never taken that style flared metal fuel line off before, maybe get some help from somebody who has. The small metal nut is very soft and easy to round the corners off of. And you have to hold the big nut behind it (that actually retains the fuel filter) still while loosening the small nut. They'll try to turn together which you DON'T want to have happen because you'll twist the metal fuel line into a pretzel.
2. Exhaust restriction. The old "banana up the tailpipe". Most common cause- the "bricks" inside the cat converter have either melted or shifted around, choking off flow.
1. Clogged fuel filter. Nobody every changes them because nobody knows where they are (except us die-hard 3rd genners). It's in the nose of the carb behind where the fuel line attaches to it. If you've never taken that style flared metal fuel line off before, maybe get some help from somebody who has. The small metal nut is very soft and easy to round the corners off of. And you have to hold the big nut behind it (that actually retains the fuel filter) still while loosening the small nut. They'll try to turn together which you DON'T want to have happen because you'll twist the metal fuel line into a pretzel.
2. Exhaust restriction. The old "banana up the tailpipe". Most common cause- the "bricks" inside the cat converter have either melted or shifted around, choking off flow.
12-30-2015, 09:39 PM
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Car: 1984 Camaro z28
Engine: L69 5.0L H.O
Transmission: Automatic
Re: '84 Z28 L69 H.O loss of power at high rpm
Do the TV cable adjustment, but if it's not that, here's your next two likely suspects:
1. Clogged fuel filter. Nobody every changes them because nobody knows where they are (except us die-hard 3rd genners). It's in the nose of the carb behind where the fuel line attaches to it. If you've never taken that style flared metal fuel line off before, maybe get some help from somebody who has. The small metal nut is very soft and easy to round the corners off of. And you have to hold the big nut behind it (that actually retains the fuel filter) still while loosening the small nut. They'll try to turn together which you DON'T want to have happen because you'll twist the metal fuel line into a pretzel.
2. Exhaust restriction. The old "banana up the tailpipe". Most common cause- the "bricks" inside the cat converter have either melted or shifted around, choking off flow.
1. Clogged fuel filter. Nobody every changes them because nobody knows where they are (except us die-hard 3rd genners). It's in the nose of the carb behind where the fuel line attaches to it. If you've never taken that style flared metal fuel line off before, maybe get some help from somebody who has. The small metal nut is very soft and easy to round the corners off of. And you have to hold the big nut behind it (that actually retains the fuel filter) still while loosening the small nut. They'll try to turn together which you DON'T want to have happen because you'll twist the metal fuel line into a pretzel.
2. Exhaust restriction. The old "banana up the tailpipe". Most common cause- the "bricks" inside the cat converter have either melted or shifted around, choking off flow.
Thanks for the suggestions
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12-31-2015, 10:59 AM
#8
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Re: '84 Z28 L69 H.O loss of power at high rpm
My first thought is restricted exhaust. If it's not too rusted, you may be able to disconnect the exhaust in front of the cat and look for a big difference in performance. Def verify the TV cable adjustment. Remember also that "rebuilt" in an automatic transmission can mean almost anything, depending on who did it.
A distributor cap that's getting carbon tracked can also cause a loss of power at high revs due to scattering of the spark.
A distributor cap that's getting carbon tracked can also cause a loss of power at high revs due to scattering of the spark.
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