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post #1 of 2 (permalink) Old 06-02-2019, 12:17 PM Thread Starter
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Join Date: May 2019
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Hello all

New to the LT1. I recently bought back my Jeep CJ-7 that I sold in 04’. At that time it had a throttle body 383 stroker. Bought it back and it now has a 95’ LT1. Had vss codes , falling on its face, and leaking like a sieve. Got the vss codes taken care of, I’ve replaced all the seals and gaskets, cleaned the msd Opti and replaced cap and rotor and new water pump while I was there.
Still falling on its face at light throttle. Idles fine except for some erratic idle rpms. I get some backfire in the exhaust when it acts up. Wierd part to me is it runs fine until it warms up and goes closed loop...
Wish I had my stroker back...
Pulling my hair out..
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post #2 of 2 (permalink) Old 06-03-2019, 07:23 AM
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Welcome to the forum.

1st thing you need to do is go to following link & download 95 service manual. It will have driveability & emissions section that can help you.

2nd thing is for you to get an obd 1 scanner that does real time sensor data. Hook car to scanner & read codes. Then do a running sensor scan. See what sensors are saying.

Don't have a clue to what sensor data means. PM me with your email address. I'll send you the pdf file "scanner readings and what they mean".

Next, put a fuel pressure gauge on fuel rail. @ key on prime pressure should be around 43 psi. Start engine, @ idle pressure should be at least mid 30's. Tape gauge to windshield, take a drive. Pressure for all driving conditions except idle should be around 40 psi.

Being a lt1 owner you need to have an oscilloscope to test opti low & high resolution signals. You can buy a pc based scope on ebay, amazon, etc for around $70. Test your low & high res signals being sent out by opti. Make sure they are the proper square wave. Also, no drop outs of signal, & no changes to waveform when engine acts up.

All this should keep you busy for a while. Report your findings when testing is done. We're go from there.
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