Possible Optispark Problem??
Thread Starter
2nd Gear
Joined: Jul 2020
Posts: 2
Likes: 0
From: Fayetteville, TN
Possible Optispark Problem??
I have a 1993 Base Corvette with 40k miles that won't start. I replaced the fuel filter and fuel pump. I can hear the fuel pump coming on when I turn the key, it cranks but won't start. I disconnected the battery when I changed my fuel pump but forgot to check for codes before I disconnected the battery. I checked for codes after I reconnected the battery but it does not show any at all. I haven't checked anything else but I wonder if it could be the Opti-spark. Seems like it would give a code even if disconnecting the battery cleared it. I'd like some advice or maybe give some ideas about what else to check. It was running fine the last time I drove it and the next day it would crank but not start. Need some advice before I pull the trigger on a new Opti-spark. BTW, I do have the service manuals for anything I need to look up. Thanks in advance guys.
Le Mans Master
Joined: May 2005
Posts: 7,328
Likes: 2,249
From: Central Maryland
As stated above, check fuel pressure while cranking.
Check for spark at one or more plugs. If spark is absent, check for spark at the coil wire. If spark is absent at the plug(s), but present at the coil wire, suspect a fault with the distributor rotor. The opti will trigger codes when most failures occur in the optical sensor section. It will not trigger codes if failures occur in the spark distribution section.
Live well,
SJW
Check for spark at one or more plugs. If spark is absent, check for spark at the coil wire. If spark is absent at the plug(s), but present at the coil wire, suspect a fault with the distributor rotor. The opti will trigger codes when most failures occur in the optical sensor section. It will not trigger codes if failures occur in the spark distribution section.
Live well,
SJW
Thread Starter
2nd Gear
Joined: Jul 2020
Posts: 2
Likes: 0
From: Fayetteville, TN
The last time it wouldn't start like this, I changed the fuel filter and it ran fine. This time, I started by replacing the fuel filter again but i wanted to also change the small filter on the pump assembly. I couldn't hear the pump when I turned the key on so I thought I would just change the pump while i had the assembly out. I should have done what you said and checked the pressure first. I don't have the pressure tester but I am going to get one. Thanks for your input!
Racer
Joined: Oct 2023
Posts: 381
Likes: 120
From: St. Petersburg, FL
If you have a Harbor Freight near by, get this.
https://www.harborfreight.com/basic-...kit-64939.html
https://www.harborfreight.com/basic-...kit-64939.html
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Burning Brakes
Joined: Jun 2021
Posts: 1,199
Likes: 449
From: NJ
You can make the procedure a one man operation with reading the gauge. It should be long enough to place on your windshield so you can read it from inside the car. Tape it in place if you have to. Note what pressure you get when key turned to on and if pressure holds after the initial pump activation. If it doesn’t come up to specs or quickly drops off, you have an internal leak somewhere. FPR, injector(s), etc. You can also pull the vacuum line off the FPR and see if there’s fuel in there. It should be dry.