Nightrider1984

So the kid I bought it from Swapped the motor and put a ls1 motor in it I will check the ground and make sure everything is tightened down should I put dialectic grease on backing of module thought I read something about that just so frustrated want this car running personally think it's pushing back to the opti again might have to just order a more promising opti

Injuneer

If it has an LS1 swap, nothing in this thread applies to the LS1 engine. They are radically different. It wouldn't have any of the components discussed here - ICM, single coil, Opti, etc.

https://www.google.com/search?client...8ltfyt0s69vbM:

The LT1, LT4, and L99 are the only GM engines that have an Optispark distributor.

Nightrider1984

Injuneer it is a lt1 I tighten all the grounds retested everything step by step on shbox site all my readings are on point from opti harness to icm to coil test lighted every fuse cranked car still no spark but getting 2 3 on meter to icm harness but watching tach still not jumping also would think opti good right? Could it be possible even tho getting reading of 3 volts on coil that might still be bad coil

Injuneer

You're not making this easy.

Confusing.... you ARE getting 2 to 3 volts on the white wire from the PCM to the ICM? And then you checked the coil and you are "getting a reading of 3 volts on coil"? Where on the coil? You need 12 volts on both sides of the coil primary.

Coil continuity check, per Shoebox:

http://shbox.com/1/coil_testing.jpg

Nightrider1984

I'm sorry injuneer never got correct info from these guys but yes it's a lt1 motor to start now as for coil I took it out and tested the resistance I'm getting 1.3 on primary and 6.5 on secondary so I'm on the money in the Chilton book..and yes when I unplugged the icm harness tested the white wire and when cranking I get 2 to 3 volts on meter I'm not seeing tach needle jump

Injuneer

You might want to read and follow the Shoebox info I have given you links to. His info is based on extensive hands-on disassembly, assembly, testing and repairs specifically on the LT1 engine. Is is considered by many (including myself) to be the "bible" for the LT1. Much more reliable than a Chilton's.

Alternatively, you can do a free download of the factory service manual for your car, courtesy of GaryDoug. It's 1996, but is virtually identical to your 1997.

https://www.mediafire.com/?40mfgeoe4ctti

And you have to answer the questions...... can't help you if you don't:

Nightrider1984

I gotcha ya I'm getting a reading of 8.25 on both sides

Nightrider1984

Injuneer wanna thank you for your help found the problem the opti harness was no good the put a new one on fired right up!!!!(

Nightrider1984

Ok so I'm having some issues when I changed the opti harness ran good no issues now I crank a few times fires up but really rough backfires sputter ...will barely run for a few unless I tap hit the gas than if let off will cut off...ran code reader had no codes now after cranking it a few time and running the car got the code p1371 again.. I hear delete code remove pcm fuse see if comes back also should I check for other things like iac or maybe a vacuum if it ain't one things it's another... has new fuel filter o2 sensors maf sensor tps sensor besides what I told in earlier post icm coil opti plugs wires...

Nightrider1984

Also weird is when key completely off than start car has power can rev up than starts to sputter gas pedal bogs down than will cut off than if key is in just the on position to just to start again will kick over and when hit the gas to rev it up complete bog no gas cuts right off and in last post vacuum leaks should I check for I meant to say feels like a air fuel problem but not a mechanic lol

Nightrider1984

Also forgot to mention when I got the car they deleted the egr not sure if that could cause something

DrewHMS97SS

I think you should start a new thread related to your car, rather than riding this one. The code you indicate points to the optispark, see this.

It is also really hard to follow what you are talking about. Could you break down steps you have taken, parts replaced, and tests you have run? It feels like we are talking about one subject, then you jump to troubleshooting something else that is unrelated.

Nightrider1984

OK I'll start a new one

newfee

Will fuel pump cut in if there’s a problem with opti

Injuneer

I'm assuming you mean "will the fuel pump run if there's a problem with the opti?"

When you turn the key to "RUN" the fuel pump should run (whether there is a problem or not) for two seconds, then shut off. If you continue and turn the key to "START" the fuel pump will not restart until the PCM sees the low resolution pulse signal from the optical cam position sensor in the Opti.

To check the fuel pump directly, to see if it is working (without turning the key), apply 12 volt power to the "Fuel Pump Prime Connector" under the hood near the PCM (note on 1996/97 the wire for connector is red):

http://shbox.com/1/fuel_pump_prime.jpg

To check if the PCM is receiving the low resolution pulse form the Opti:

- does the tach needle move up a couple hundred RPM when the starter is cranking the engine?

- test the white wire from the PCM to the ICM per Shoebox's procedure:

4th Gen LT1 F-body Tech Articles