Please Help
Thread Starter
Cruising
Joined: Sep 2018
Posts: 11
Likes: 1
Please Help
My father and I have been working on my 'Vette for a while now, mainly to fix a glaring issue. My 1994 base 'Vette has a tendency to quit in the middle of a drive, seemingly random. No sputter, no running rough, and no unusual noises, however it will die at random times. Not only is this dangerous, it is also extremely embarrassing to be stuck in the middle of a turn lane while the 5 o'clock traffic builds up behind you. We have determined that the fuel pump isn't the problem, and we have replaced the coil and ICM to no avail. We are starting to get quite frustrated. To all fellow C4 owners, please help us!
Thank you,
Brody
UPDATE:
Through everyone's great input, we've determined that the issue is the Optispark, or the distributor. Thank you everyone for the help!
Thank you,
Brody
UPDATE:
Through everyone's great input, we've determined that the issue is the Optispark, or the distributor. Thank you everyone for the help!
Last edited by Brody Paulk; Sep 19, 2018 at 10:03 PM.
Thread Starter
Cruising
Joined: Sep 2018
Posts: 11
Likes: 1
Code reader
We do, however our code reader isn't getting a connection, and because of that we have been working blind. We considered fixing that issue however we decided that our other issue is more pressing.
Melting Slicks
Joined: Oct 2016
Posts: 2,024
Likes: 363
From: Central Alabama
Your 94 will display the codes on the LCD (speedometer) all you need is a paper clip.
Follow this link and scroll down to the section labeled-Sequenced Code Recovery - 1994 through 1996:
how to pull codes
While the connector looks like an OBD-II connector it is really OBD-I so an OBD-II reader will not work.
Follow this link and scroll down to the section labeled-Sequenced Code Recovery - 1994 through 1996:
how to pull codes
While the connector looks like an OBD-II connector it is really OBD-I so an OBD-II reader will not work.
Burning Brakes
Joined: Feb 2013
Posts: 769
Likes: 95
From: Central Pennsylvania
Do have any prior history of the Opti? 2 of my C4’s are LT1’s and I replaced in both at least once. Mine starting stalling, sometimes they would run flawlessly. Kept getting worse. At one point, the cars would stall, then resart after about 1/2 hour.
May be something else, but you should check the usual culprits, fuel pressure, injectors (noid light), failing fuel pump etc
there are plenty of threads on CF concerning the issues you are having
try not to just throw parts at it!
good luck
May be something else, but you should check the usual culprits, fuel pressure, injectors (noid light), failing fuel pump etc
there are plenty of threads on CF concerning the issues you are having
try not to just throw parts at it!
good luck
Thread Starter
Cruising
Joined: Sep 2018
Posts: 11
Likes: 1
It's my understanding that the connector for the code reader has sixteen prongs, or holes, and that is for a OBD-II, unlike the OBD-I reader with twelve prongs, or holes. Are you sure it is operated like the old OBD-I connections?
Race Director
Joined: Oct 2011
Posts: 16,089
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From: Dallas Texas
2025 C4 of the Year Finalist - Modified
Team Owner
Joined: Feb 2003
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From: Sitting in his Nowhere land Hanover Pa
2024 C2 of the Year Finalist - Unmodified
2015 C2 of Year Finalist
Is the check engine light on? If not your only going to get history codes. When it dies you need to check for fuel and spark. Plugging it into a scanner and watching the sensor readings to see if they are where they need to be can be helpful.
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Thread Starter
Cruising
Joined: Sep 2018
Posts: 11
Likes: 1
EDIT:
Through everyone's great input, we've determined that the optispark has gone bad, thank you for everyone's help!
Last edited by Brody Paulk; Sep 19, 2018 at 10:01 PM.
Thread Starter
Cruising
Joined: Sep 2018
Posts: 11
Likes: 1
Thank you, that achieved a code readout, reading C12, H16, --- and based on the Haynes manual, my distributor/optispark has gone bad, thank you so much for the help
Last edited by Brody Paulk; Sep 19, 2018 at 09:52 PM.
Burning Brakes
Joined: Dec 1999
Posts: 984
Likes: 154
From: Columbia MD
My father and I have been working on my 'Vette for a while now, mainly to fix a glaring issue. My 1994 base 'Vette has a tendency to quit in the middle of a drive, seemingly random. No sputter, no running rough, and no unusual noises, however it will die at random times. Not only is this dangerous, it is also extremely embarrassing to be stuck in the middle of a turn lane while the 5 o'clock traffic builds up behind you. We have determined that the fuel pump isn't the problem, and we have replaced the coil and ICM to no avail. We are starting to get quite frustrated. To all fellow C4 owners, please help us!
Thank you,
Brody
Thank you,
Brody
-Wes
Race Director
Joined: Oct 2008
Posts: 17,982
Likes: 1,074
From: Lansing MI
Thread Starter
Cruising
Joined: Sep 2018
Posts: 11
Likes: 1
When the car dies, it doesn't sputter, stick, or anything of that nature, and when you turn it on, not crank it up, you can hear the pump prime without issue. And we checked fuel pressure and it was optimal.
Race Director
Joined: Oct 2011
Posts: 16,089
Likes: 819
From: Dallas Texas
2025 C4 of the Year Finalist - Modified
There is a harness that goes connects to the opti. It goes up to passenger side fuel rail. Disconnect it and look at the pins for cleanliness and corrosion. Do you have a noid light set? If so, when the car stalls, plug it into an injector connector. Try and start the car. Does the noid light pulse, aka does it light up? If not, the code h16 is valid. When h16 occurs, it doesn't send a pulse to injectors. Which obviously, will not let the car start.
For what it's worth, I put a new opti in my 93(from sac city) and it always had the h16. But ran great. After researching that, many said if the car is running fine, ignore the h16. The reason the h16 stays is because there is an optical sensor in the optispark. They were originally made by Mitsubishi and were very robust. They no longer make them, and we believe that is why the h16 stays, even if the car is running great.
But your's stalls out. So pursue it. Sorry for all the info.
For what it's worth, I put a new opti in my 93(from sac city) and it always had the h16. But ran great. After researching that, many said if the car is running fine, ignore the h16. The reason the h16 stays is because there is an optical sensor in the optispark. They were originally made by Mitsubishi and were very robust. They no longer make them, and we believe that is why the h16 stays, even if the car is running great.
But your's stalls out. So pursue it. Sorry for all the info.
Thread Starter
Cruising
Joined: Sep 2018
Posts: 11
Likes: 1
There is a harness that goes connects to the opti. It goes up to passenger side fuel rail. Disconnect it and look at the pins for cleanliness and corrosion. Do you have a noid light set? If so, when the car stalls, plug it into an injector connector. Try and start the car. Does the noid light pulse, aka does it light up? If not, the code h16 is valid. When h16 occurs, it doesn't send a pulse to injectors. Which obviously, will not let the car start.
For what it's worth, I put a new opti in my 93(from sac city) and it always had the h16. But ran great. After researching that, many said if the car is running fine, ignore the h16. The reason the h16 stays is because there is an optical sensor in the optispark. They were originally made by Mitsubishi and were very robust. They no longer make them, and we believe that is why the h16 stays, even if the car is running great.
But your's stalls out. So pursue it. Sorry for all the info.
For what it's worth, I put a new opti in my 93(from sac city) and it always had the h16. But ran great. After researching that, many said if the car is running fine, ignore the h16. The reason the h16 stays is because there is an optical sensor in the optispark. They were originally made by Mitsubishi and were very robust. They no longer make them, and we believe that is why the h16 stays, even if the car is running great.
But your's stalls out. So pursue it. Sorry for all the info.