LTX and LSX Putting LT1s, LS1s, and their variants into Third Gens is becoming more popular. This board is for those who are doing and have done the swaps so they can discuss all of their technical aspects including repairs, swap info, and performance upgrades.

1986 Iroc with 93-94 LT1 Swap

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Old Nov 2, 2025 | 12:33 PM
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86IRocGen2LT1's Avatar
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1986 Iroc with 93-94 LT1 Swap

I'm new to this forum and appreciate being added. I'm excited about a car that’s new to me and looking forward to getting it running. The VIN indicates that it originally had a carbureted 305 engine, but when I opened the hood, I found an LT1 engine installed. I hope that whoever did the installation managed to properly redo the wiring so that the dashboard gauges and other components will work. So far, I have cleaned out the engine bay, which had 20 years' worth of debris and rat nests. The sides were filled with nesting material, and I found chewed wires for the injector plugs—it's quite a disaster. As I mentioned, I've cleaned the engine bay, changed the oil, disconnected the fuel pump relay, and installed a new battery. I sprayed some starter fluid into the intake and managed to get the engine to turn over and run for a few seconds.

I went out a few days later and disconnected the fuel lines going into the fuel rail and reconnected the F/P relay in hopes of forcing the old gas out, but when I did, I did not hear the Fuel pump hum, so that could be either bad wiring/chewed wiring, or a bad Fuel pump, etc. However, I’m facing issues with no interior lights or sounds, and I'm not sure where to begin troubleshooting. Additionally, the ECM has been mounted where the windshield washer fluid reservoir should go, which seems strange. I would appreciate any recommendations for my next steps, and I can post pictures of what I'm dealing with if that would help. Thank you!
How I found it!
How I found it!
After a vacum!
After a vacum!
After washing it and getting all the rats' nests and dirt out!
After washing it and getting all the rats' nests and dirt out!
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Old Nov 2, 2025 | 01:32 PM
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Tom 400 CFI's Avatar
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Re: 1986 Iroc with 93-94 LT1 Swap

I'd get a test light or meter, locate a good ground, then use the testing device to test for power at all the fuses in the fuse box. That's where *I* would start. THEN, I'd move toward power train electrical diag.
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Old Nov 2, 2025 | 01:46 PM
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86IRocGen2LT1's Avatar
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Re: 1986 Iroc with 93-94 LT1 Swap

That was also a good starting point for me, and I have verified power going to everything connected to a fuse in the fuse box under the hood as well as under the dash.
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Old Nov 2, 2025 | 02:38 PM
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Car: 1967 Camaro, 91 z28
Engine: Lb9
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Re: 1986 Iroc with 93-94 LT1 Swap


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Old Nov 3, 2025 | 09:42 AM
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Tom 400 CFI's Avatar
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From: Park City, UT
Car: '92 Corvette, '89 1/2-a-'Vette
Engine: LT1, L400
Transmission: ZF6, T5
Axle/Gears: 3.45, 3.31
Re: 1986 Iroc with 93-94 LT1 Swap

Originally Posted by 86IRocGen2LT1
I have verified power going to everything connected to a fuse in the fuse box under the hood as well as under the dash.
In that case, it should be pretty easy to chase out these issues individually....
Originally Posted by 86IRocGen2LT1
However, I’m facing issues with no interior lights or sounds, and I'm not sure where to begin troubleshooting.
....and the fuel pump etc as well.
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