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1992 z28 5.7

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Old 11-11-2023, 04:38 PM
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1992 z28 5.7

Hi guys , I really need some help here. 1992 z28 5.7. 130,000 miles rebuilt engine with 3000 miles. Ran well last year. Put the car in the garage for 6 months, disconnected the battery. Came back car won’t start. Tested the fuel pump which was replaced last year and that’s good. Looks like the engine is not getting spark. Bought a new ignition module and installed it thinking that could be the problem. Still no spark. I have limited electrical diagnostic tools. Can someone tell me where to look ? PLEASE….
Old 11-11-2023, 04:46 PM
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Re: 1992 z28 5.7

Are you sure it's a spark issue and not fuel? Injectors can start sticking after sitting. How's the ignition coil?
Old 11-11-2023, 04:51 PM
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Re: 1992 z28 5.7

I’m leaning toward the spark issue. As fas as I’m aware of when the engine is turned over you should have spark at the plugs. Not saying coils don’t go bad but they usually don’t . However that is a possibility.
Old 11-11-2023, 05:12 PM
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Re: 1992 z28 5.7

I think those cars have a vats system that either kills spark or fuel. It's an anti theft thing. It may be a component here. Idk much about that system but I'm pretty sure your car has it.
Old 11-11-2023, 05:35 PM
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Re: 1992 z28 5.7

I had a chip burnt that supposedly deleted the vats. I have two resistor keys and neither gets me spark.
Old 11-11-2023, 06:36 PM
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Re: 1992 z28 5.7

Originally Posted by Firechicken82
I think those cars have a vats system that either kills spark or fuel. It's an anti theft thing. It may be a component here. Idk much about that system but I'm pretty sure your car has it.
Originally Posted by Lisa Keefer
I had a chip burnt that supposedly deleted the vats. I have two resistor keys and neither gets me spark.
Hi Lisa,

VATS has absolutely nothing to do with the ignition system, VATS, if not satisfied, kills two things and two things only; The starter's ability to crank the engine, and the fuel injector's ability to spray fuel.
Providing that lack of spark truly is what's keeping it from running, VATS ain't the guilty party here. Do you have a voltmeter (Multimeter) and know how to use it? If so a couple of quick checks would be a voltage reading of the fat pink wire going to the ignition coil, and a resistance reading of the distributor's pick up coil....
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Old 11-12-2023, 10:11 AM
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Re: 1992 z28 5.7

I'm going to suggest something dumb that you might have already done.

Check all your fuses.

Also, check your wiring harness for any bite marks, perhaps a signal or power wire was broken by a small animal?
Old 11-12-2023, 02:00 PM
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Re: 1992 z28 5.7

Guys, thanks for your help in diagnosing my ignition problem. I have no spark at the plug. I have 12 volt’s coming in to the coil when the key is in the on position however I have nothing going to the distributor? Must I crank the engine to get the 12 volts into the distributor or do should I have 12 volts going to the distributor when the key is on ? Thanks
Old 11-12-2023, 07:10 PM
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Re: 1992 z28 5.7

Originally Posted by Lisa Keefer
Guys, thanks for your help in diagnosing my ignition problem. I have no spark at the plug. I have 12 volt’s coming in to the coil when the key is in the on position however I have nothing going to the distributor? Must I crank the engine to get the 12 volts into the distributor or do should I have 12 volts going to the distributor when the key is on ? Thanks
Hi Lisa, I'm curious, does this have a separate ignition coil, or is the coil built into the distributor cap?
Old 11-13-2023, 09:33 AM
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Re: 1992 z28 5.7

Originally Posted by OrangeBird
Hi Lisa, I'm curious, does this have a separate ignition coil, or is the coil built into the distributor cap?
It does have a separate ignition coil.
Old 11-13-2023, 11:54 AM
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Re: 1992 z28 5.7

There’s a plug behind the distributor. Male connector marked a and b the wires are red or pink with a white stripe and gray or tan. The connection comes out of the wiring harness that runs behind the firewall behind the distributor. Does anyone know where this connects please??? Thank you sorry can’t post a pic because I don’t know how.
Old 11-13-2023, 03:24 PM
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Re: 1992 z28 5.7

Originally Posted by Lisa Keefer
There’s a plug behind the distributor. Male connector marked a and b the wires are red or pink with a white stripe and gray or tan. The connection comes out of the wiring harness that runs behind the firewall behind the distributor. Does anyone know where this connects please??? Thank you sorry can’t post a pic because I don’t know how.
https://www.thirdgen.org/forums/elec...tery-plug.html by chance do you mean this?
Old 11-14-2023, 04:01 PM
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Re: 1992 z28 5.7

Might sound dumb, but pull the distributor cap off, have someone try the starter. Does the rotor on the dist. shaft turn? There is also a pickup coil that hooks to the new module, might replace that too. Check the inside of the dist. cap and rotor for any major tracking or break, especially around that center terminal. After all that, about have to be a bad coil (or coil to cap wire.)
Old 11-14-2023, 05:41 PM
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Re: 1992 z28 5.7

Originally Posted by Firechicken82
Are you sure it's a spark issue and not fuel? Injectors can start sticking after sitting. How's the ignition coil?
I have replaced the icm, icm, and put in a new battery, 300.00 later still no spark
Old 11-14-2023, 05:44 PM
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Re: 1992 z28 5.7

Thanks I’ll check all that.
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