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1992 Corvette Crank, no Start

 
Old 04-11-2019, 10:26 PM
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Jtgt350
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Default 1992 Corvette Crank, no Start

1992 Corvette Cranks (turns over) but won't start. I'm a novice, so please bear with me. I'm also somewhat limited on funds, and would like to diagnose if possible exactly where my problem is, instead of blindly swapping parts (and spending a fortune) and guessing. I've read so many threads on Optisparks, coils, Noid lights, fuel filters, and ECM's being culprits that my head is spinning, and I don't have a sophisticated oscilloscope or high tech readers like many on this site say is necessary to pinpoint a problem. I've had the car about a year. The guy I bought it from told me it had a new Water Pump, Optispark, and ECM, but it all looks original (dirty, and water pump looks like it leaked at some point from the weep hole) so I'm very skeptical about that (although I do see the plug wire boots at the Optispark marked with wite-out as if somone took them off at one time. Just before it died in my garage, it felt like it had limited power (thought maybe it was a clogged converter or fuel filter) felt like it struggled to break 50 mph on local back roads - didn't take it on the highway to try it though. So far, I checked Fuel Pressure, and it is good (40 psi) and holds pressure for about an hour. Haven't checked spark because I'm confused as to where to check it (have read each plug, at coil, etc.). Car seems to crank fine, just won't turn over. Although fuel pressure is good, I don't smell any when trying to start it.

If someone could give me some solid steps to check after Fuel pressure, I'd appreciate it. I know I need to check spark (I have a spark tester), just not sure where to check it from (directly from coil, at plugs, from Optispark, etc.). I don't want to head straight for Optispark unless I know for certain that's where the problem is for sure.

Thanks in advance for any help!
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Old 04-12-2019, 12:31 AM
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Blackcorvette_85
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shouldnt matter to much where you check the spark at, just needs to be inline between the opti and the plug, either side will work, what ever is easiest to see from where you can crank it should be fine. Check at least two plugs to be sure, but probably shouldn't need to do more than that. Never had an opti system, so not sure on their failure points, but with a spark checker that should give you a good idea. If it has a separate coil, then if your not getting spark at the plug, check if your getting voltage from the coil next. If youve got power going into the opti and no spark going to the plug, thats probably the problem. Maybe another vette guy with one can give ya a little more, but thats the basics of checking for spark.
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