Sick '92 LT1...
Thread Starter
Race Director
Joined: Jul 2000
Posts: 14,075
Likes: 18
Sick '92 LT1...
...and not the good kind of sick...
About a month ago my car began to hesitate under full throttle acceleration when it hit 3500-4000 RPM. It was intermitant, like it was still not fully warmed up. Now it acts like the rev limitter is set at 4K. It cleared up for a while this morning but when I went out this evening it was back. It's got 115K miles on it... the rest is in the sig.
Anyone else ever have this problem that can give me a fix..?
About a month ago my car began to hesitate under full throttle acceleration when it hit 3500-4000 RPM. It was intermitant, like it was still not fully warmed up. Now it acts like the rev limitter is set at 4K. It cleared up for a while this morning but when I went out this evening it was back. It's got 115K miles on it... the rest is in the sig.
Anyone else ever have this problem that can give me a fix..?
Elite Torch Red Member
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From: Exit 89 GSP,Lakewood,NJ The Land Of Mojo
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Re: Sick '92 LT1... (Craig Brumley)
1st thing everyone will say is the opti.
In my '95 it was the coil wire touching the waterpump causing a miss. Easy fix.
In my '93, I had two plug wires rubbing on the exhaust manifolds, another easy fix. But then the opti crapped out and teh symptoms were just as you described.
The more a car sits the more likely the opti will crap out sooner than if it was driven a lot. Since you have 115,000 miles, do you know the last time if ever that the opti was replaced?
In my '95 it was the coil wire touching the waterpump causing a miss. Easy fix.
In my '93, I had two plug wires rubbing on the exhaust manifolds, another easy fix. But then the opti crapped out and teh symptoms were just as you described.
The more a car sits the more likely the opti will crap out sooner than if it was driven a lot. Since you have 115,000 miles, do you know the last time if ever that the opti was replaced?
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Joined: Sep 2001
Posts: 83
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From: Longview Texas
Re: Sick '92 LT1... (Craig Brumley)
Had a similar situation on my 92. replaced the oxygen sensors and that helped a bit, but the problem was in the opti. I got a short-term fix by replacing the cap - the carbons in there were totally worn out. Now 2 years later I have rebuilt the silly opti and have run into other non-related problems.
One of these days I'll just say @&&$)@# and go over to Lingenflelters I think.... :flag
One of these days I'll just say @&&$)@# and go over to Lingenflelters I think.... :flag
Le Mans Master
Joined: Oct 2000
Posts: 6,362
Likes: 30
From: Oak Harbor WA
Re: Sick '92 LT1... (Craig Brumley)
Before diving into a full blown Opti replacement I would verify a few things first.
1. Air cleaner is good.
2. Plugs and wires are in good condition.
3. Not running 3 yr old gas.
4. Not shorts from the plug wires and coil wires as Mojo stated.
5. No vacuum leaks of any kind.
6. Rem/Repl the fuel filter.
7. Find another local 92-95 model and borrow their coil and ignition module to use and see if it goes away.
8. Verify fuel pressures at idle and WOT.
Then replace the opti.
1. Air cleaner is good.
2. Plugs and wires are in good condition.
3. Not running 3 yr old gas.
4. Not shorts from the plug wires and coil wires as Mojo stated.
5. No vacuum leaks of any kind.
6. Rem/Repl the fuel filter.
7. Find another local 92-95 model and borrow their coil and ignition module to use and see if it goes away.
8. Verify fuel pressures at idle and WOT.
Then replace the opti.
Thread Starter
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Re: Sick '92 LT1... (Mr Mojo)
...did the "opti" thing a year ago. The previous owner had replaced the coil and didn't get the coil wire on good. The result was, after a couple of years of arcing, it blew the end off the cap at the coil wire...and a ride on a flat-bed.
The thing I don't get is it was acting up all last weekend; then fine this morning, then bad again tonight. It starts and runs fine except under heavy accelleration, and then only intermitantly; and it's all or nothing.
The thing I don't get is it was acting up all last weekend; then fine this morning, then bad again tonight. It starts and runs fine except under heavy accelleration, and then only intermitantly; and it's all or nothing.
Safety Car
Joined: Feb 2002
Posts: 4,212
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From: Sun City West Az
Re: Sick '92 LT1... (Craig Brumley)
IF you think the opti is ok, then I'd be looking hard at the coil and coil driver. One or both will crap out under hard accel. if they are on thier way out.
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Thread Starter
Race Director
Joined: Jul 2000
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Re: Sick '92 LT1... (BAM92)
I did the fuel pump and filter thing last year while I was into the distributer. This really feels like it's throttle position related.
I'm driving it up to Road Atlanta this afternoon to watch a buddy run around the track; maybe today it will be feeling better...or fail all the way while I'm out in the middle of nowhere...
I'm driving it up to Road Atlanta this afternoon to watch a buddy run around the track; maybe today it will be feeling better...or fail all the way while I'm out in the middle of nowhere...
Thread Starter
Race Director
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Re: Sick '92 LT1... (Craig Brumley)
Yep...ran fine yesterday, including a couple of WOT tests to 5K+
...I don't get it...[shrug]
Good time at the track, too. Didn't get to drive but had a good time lapping in the passenger seat of a friends BMW 2002.
...I don't get it...[shrug]
Good time at the track, too. Didn't get to drive but had a good time lapping in the passenger seat of a friends BMW 2002.
Le Mans Master
Joined: Oct 2000
Posts: 6,362
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From: Oak Harbor WA
Re: Sick '92 LT1... (Craig Brumley)
Mine was doing stuff as you describe and so I opted out of "Opti" and installed the LTCC and it is perfect now. My guess is it is the interior of the Opti doing the spark scatter thing. You live in an area of extreme humidity and that plays a role in this.
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Re: Sick '92 LT1... (Goody)
Mine was doing stuff as you describe and so I opted out of "Opti" and installed the LTCC and it is perfect now. My guess is it is the interior of the Opti doing the spark scatter thing. You live in an area of extreme humidity and that plays a role in this.
Melting Slicks
Joined: Jul 1999
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From: Olive Branch (Memphis suburb) MS
Cruise-In II Veteran
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From: Lake Wylie SC
Re: Sick '92 LT1... (Ramrod92)
After looking at the pictures, we need someone to make a nice cover for this setup.
Burning Brakes
Joined: Oct 2001
Posts: 1,135
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Re: Sick '92 LT1... (Craig Brumley)
...and not the good kind of sick...
About a month ago my car began to hesitate under full throttle acceleration when it hit 3500-4000 RPM. It was intermitant, like it was still not fully warmed up. Now it acts like the rev limitter is set at 4K. It cleared up for a while this morning but when I went out this evening it was back. It's got 115K miles on it... the rest is in the sig.
Anyone else ever have this problem that can give me a fix..?
About a month ago my car began to hesitate under full throttle acceleration when it hit 3500-4000 RPM. It was intermitant, like it was still not fully warmed up. Now it acts like the rev limitter is set at 4K. It cleared up for a while this morning but when I went out this evening it was back. It's got 115K miles on it... the rest is in the sig.
Anyone else ever have this problem that can give me a fix..?
1 Vote for a clogged cat! :yesnod:
