95 c4 ecu
Le Mans Master
Joined: Sep 2013
Posts: 6,192
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From: near the thumb in the mitten
I believe they are " one size fits all" you will need to have it programmed to your car. So Impala Roadmaster Fleetwood Firebird z28 should all be the same number. Ebay lists several venders for them. Dealer reflash is probably 100. or more. So 200 or less programmed is a good deal
Last edited by Kevova; Apr 8, 2018 at 06:35 PM.
Team Owner
Joined: Sep 2003
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Programming wouldn't be a 'parts dept' function but I would have thought they might have referred you to service. They might require their diagnostics before even discussing programming.
Last edited by WVZR-1; Apr 8, 2018 at 06:11 PM.
Le Mans Master
Joined: Sep 2013
Posts: 6,192
Likes: 750
From: near the thumb in the mitten
Programming is going to be iffy because of age. Some dealers didn't keep the necessary equipment it doesn't has to be a chevy dealer, all GM dealers were also reflashing ecms in the nineties so call around, the older the dealer in same location the better. An old dealer that never moved may have what you need gathering dust in a corner. You may have send PCM to a service center.
Thread Starter
Heel & Toe
Joined: Apr 2018
Posts: 20
Likes: 1
Ive replaced the distributor( cant think of the actual name of it. for some reason the words all spark are coming to mind. Lol ) , the coil and the icm. Still no spark. The general mechanic i took it to says the computer is not working and all he knows to do is replace it. Ive owned 6 third gen camaro's. This is my first vette. Its way different from a 89 iroc z. I dont really know where to get this issue fixed. The car turns over but will not start. And before that happened it would run fine until about 4500 RPMs. Then it would spit and sputter. It did that for about 45 minutes until I got to my house. I'll turn the car off I went inside called the mechanic he said bring him the car. When I walked back outside it just wouldn't crank. And the day before that it did this weird thing where it shut off on me three times while I was driving it. So I would pull over put it in park and then crank back up. I knew the exhaust was old, and thought that might be an issue. I took it to a friend's muffler shop and had a stopped up converter. I replaced both converters and the next day is when it started throwing fits.
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Instructor
Joined: Sep 2017
Posts: 132
Likes: 21
From: By the redwoods via New Hampshire
I'd say a little more diagnosis is in order. With that said, if you need a replacement call Mark at Mirrock Corvette. He will definitely help you out. I want to say I even saw one or more 95 Vettes in his just arrived section. Given the same year and options it should be plug and play. Marks a really great guy with more than good prices. Think he's a member here, too.
Mirrock Corvette
Mark Madeira
724-717-2330
Website same as the name no space and .com
Mirrock Corvette
Mark Madeira
724-717-2330
Website same as the name no space and .com
Last edited by Palanon; Apr 8, 2018 at 08:15 PM.
Thread Starter
Heel & Toe
Joined: Apr 2018
Posts: 20
Likes: 1
Im kind of a Diyer. Im a good parts changer. Diagnostics is a thing im not too good at. I found a guy named Jon in oklahoma city today that says he can repair these in most cases and reprogram them. Im going to give the corvette dealer a call in the morning. Thanks for the help guys. Whatever you reprogram one of these ecu's to delete the skip shift, What does that mean?
Instructor
Joined: Sep 2017
Posts: 132
Likes: 21
From: By the redwoods via New Hampshire
When in first gear and you try to shift to 2nd gear below 20mph or I think 30% throttle, the car tries to force you to shift to 4th gear (obviously standard tranny). Blipping the throttle fools the skip shift. Also, there are cheap ($12) plug covers you can install on the transmission that eliminate that. Takes 5 minutes or less. The 2 to4 light will still come on but you can shift normally with no interference.
Le Mans Master
Joined: Sep 2013
Posts: 6,192
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From: near the thumb in the mitten
If you have the factory manuals re check following no start chart. It's possible you have a new faulty part. The PCM is the last component and if it still doesn't start? If you don't have factory manuals you need to get them. Also check condition of opti jumper harness, make sure terminals aren't spread.
Thread Starter
Heel & Toe
Joined: Apr 2018
Posts: 20
Likes: 1
The Opti and harness are new. After replacing them I figured out the old one wasn't bad to start with. I do have the manual and I was wondering if it wasn't the Vats that is stopping the cranking issue. But I have no idea how to even check that
Le Mans Master
Joined: Sep 2013
Posts: 6,192
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From: near the thumb in the mitten
VATS turns off ignition, fuel pump,& starter so if most of that works probably not VATS. VATS can also set code. Since you have manual are you following Chart A-3 Cranks but Won't Start?
Thread Starter
Heel & Toe
Joined: Apr 2018
Posts: 20
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I havent thought of looking in the manual for this problem until you mentioned it. The wires going from the computer down to the optispark were melted. I will look in the manual whenever I get home after work today.
Le Mans Master
Joined: Oct 2004
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From: Everett WA
C4 of Year Finalist (appearance mods) 2019
I know you said that you're handy and a good parts replacer but not that involved with diagnostics. I have to tell you as a long time 95 owner that the C4 is not a car that you want to throw parts at in an attempt to solve a problem. That can get expensive very quickly.
That's why you were asked if you have the two volume 1995 FSM. It has the diagnostic charts and they come very handy.
You said that you replaced the opti and then discovered that your original one was still good. I'll bet that if you took a pole on here the overwhelming advice would be to put the original opti spark back in the car prior to continuing to diagnose your problem.
When you put the new optispark in the car .... were you able to slide the pin drive on the cam into the square slot on the opti using just your hands? If you had to force it in any way it may well not be lined up correctly and your timing is off.
That's why you were asked if you have the two volume 1995 FSM. It has the diagnostic charts and they come very handy.
You said that you replaced the opti and then discovered that your original one was still good. I'll bet that if you took a pole on here the overwhelming advice would be to put the original opti spark back in the car prior to continuing to diagnose your problem.
When you put the new optispark in the car .... were you able to slide the pin drive on the cam into the square slot on the opti using just your hands? If you had to force it in any way it may well not be lined up correctly and your timing is off.
Thread Starter
Heel & Toe
Joined: Apr 2018
Posts: 20
Likes: 1
Ok guy's im stumped. I replaced the computer. I now have power to the opti and power to the coil. I replaced the opti twice and the coil. I still have no spark. How can i have power to both components and no spark coming out of the coil?
Thread Starter
Heel & Toe
Joined: Apr 2018
Posts: 20
Likes: 1
Code 42 has popped up. Wiring going onto distributor has been repaired. I believe im suppose to be getting 4 to 5 volts from the computer. Only reading 2.3 to 2.5. Could this be a pmc issue that wasnt vrooectly tepaired?