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1989 Auto engine knock on deceleration.
Thread Starter
Burning Brakes
Joined: Jul 2006
Posts: 833
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From: Mexico NY
1989 Auto engine knock on deceleration.
Hey guys. Happy New Year.
I have a 1989 with 100k miles.
I'm getting a knock when I let off the throttle so on the way up to say 3500 rpm it's smooth but when it's deceleration, I hear a knock.
Any way to determine if this is a serious issue (rod bearing ?)
I have removed the belt and the symptoms persist.
It's been a month or so nut I did reset the timing.
Has about 29 ish oil pressure.
Possibly related, the car also seems to not like to rev over 2800 rpm while driving.. like it runs out of breath.
I appreciate any thoughts on this.
Tim Gorman
I have a 1989 with 100k miles.
I'm getting a knock when I let off the throttle so on the way up to say 3500 rpm it's smooth but when it's deceleration, I hear a knock.
Any way to determine if this is a serious issue (rod bearing ?)
I have removed the belt and the symptoms persist.
It's been a month or so nut I did reset the timing.
Has about 29 ish oil pressure.
Possibly related, the car also seems to not like to rev over 2800 rpm while driving.. like it runs out of breath.
I appreciate any thoughts on this.
Tim Gorman
Melting Slicks
Joined: Sep 2010
Posts: 2,422
Likes: 202
29lbs oil pressure at idle.?
Fairly low. Comparing all of my F- body TPI cars.
IAC & TPS values within spec. Wires. Up to date.
You bridged the ALDL terminas A & B
Disconnected the EST lead. Correct.
validate your fuel pressure at the rails.
With your best EFI friend. The one and only.
fuel pressure gauge. Post your results
Fairly low. Comparing all of my F- body TPI cars.
IAC & TPS values within spec. Wires. Up to date.
You bridged the ALDL terminas A & B
Disconnected the EST lead. Correct.
validate your fuel pressure at the rails.
With your best EFI friend. The one and only.
fuel pressure gauge. Post your results
Melting Slicks
Joined: Feb 2003
Posts: 2,677
Likes: 812
From: Saskatoon Sask.
29lbs oil pressure at idle.?
Fairly low. Comparing all of my F- body TPI cars.
IAC & TPS values within spec. Wires. Up to date.
You bridged the ALDL terminas A & B
Disconnected the EST lead. Correct.
validate your fuel pressure at the rails.
With your best EFI friend. The one and only.
fuel pressure gauge. Post your results
Fairly low. Comparing all of my F- body TPI cars.
IAC & TPS values within spec. Wires. Up to date.
You bridged the ALDL terminas A & B
Disconnected the EST lead. Correct.
validate your fuel pressure at the rails.
With your best EFI friend. The one and only.
fuel pressure gauge. Post your results
Is there. A purpose to. your unique writing. Style? You seem to be. quite knowledgeable but. It is hard to. Follow your. train of. Thought.
Melting Slicks
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Sounds like a rod and a dead cylinder. Pull the spark plugs, do a comp test. While plugs are out move crank pulley back and forth and see what you feel. Any smoking? Especially on de-acceleration?
Advanced
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Great content in The Admiral's posts. You can learn a lot if you're not hung up on his style. When I was looking for a reference indicating the LT1 and LT4 are/are not interference engines, he did an experiment demonstrating that they are. You lose if you don't pay attention. Jim
Melting Slicks
Joined: Feb 2003
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From: Saskatoon Sask.
Great content in The Admiral's posts. You can learn a lot if you're not hung up on his style. When I was looking for a reference indicating the LT1 and LT4 are/are not interference engines, he did an experiment demonstrating that they are. You lose if you don't pay attention. Jim
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did you check the fuel pressure yet? if it’s too low clearly it can’t get enough fuel to sustain the power it is supposed to make.
do you have catalytic converters on the exhaust? If the exhaust is clogged, again it won’t be able to get enough fresh air- less o2 -less power.
I just bought a scan tool and I would definitely recommend one, there are so many issues that can potentially be figured out. For example I just noticed my throttle toggle at the throttle body was blocked by the intake tube clamp and was wondering why the tps would only read up to 80%
with the pedal at the floor. you could then log knock counts/ timing retard.
do you have catalytic converters on the exhaust? If the exhaust is clogged, again it won’t be able to get enough fresh air- less o2 -less power.
I just bought a scan tool and I would definitely recommend one, there are so many issues that can potentially be figured out. For example I just noticed my throttle toggle at the throttle body was blocked by the intake tube clamp and was wondering why the tps would only read up to 80%
with the pedal at the floor. you could then log knock counts/ timing retard.
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Moderators. Please.. Elect. forum bullies. Route. All. Ebonics, SMS. As editing team.
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Amusing, mental break-down tantrums. Forehead aneurysm bulging. Deciphering 45% of Ebonics/ SMS headlined / posts.
Hornet nest. Team of hostile dults. Egregious, ranting, bullying.! using emojis. simply brilliant.
Good luck. Building a delusional. portfolio. Winning. a world renowned Pulitzer prize award. Within. a "volunteer" car forum.
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Boasting. superior Education.
Yet... Struggling, comprehension.
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Yet... Struggling, comprehension.
Try this. Should. Overload, short circuit. Yourselves.
"S1M1L4RLY, Y0UR M1ND 15 R34D1NG 7H15 4U70M471C4LLY W17H0U7 3V3N 7H1NK1NG 4B0U7 17."
https://www.livescience.com/18392-re...led-words.html