So I’ve now owned my C3 for a little over a month now and it’s been having many issues since buying. Im now at the point where the car won’t start anymore. While I was driving home one day the engine completely seized up in the middle of the road leaving me having to push it back home since it would no longer start again after it shut off. Before it completely gave out the previous days before it was showing signs of running a lot rougher/wanting to shut off while driving and while at idle. Could this be a fuel pump issue? Fuel injection system issue? I’m kinda at a loss for what the issue could be.. just hoping it isn’t the engine itself considering there is only 9800 miles on it to date.. any advice on where to begin troubleshooting would be much appreciated! The pics I’ll post will include all the engine components and fuel injection system.










Been running 91 pump gas since AZ doesn’t have 93… but I was never told it needed 93 before buying so I’m also hoping this hasn’t caused this issue.

 

Sounds like a failing ignition module to me

 

"Seized" has a specific meeting. Did you just mean that it quit running?
Does it turn over with the starter?
Does it try to light off?
Or nothing at all?

 

correct.

 

Does it turn over with the starter?
Does it try to light off?
Or nothing at all?
I have plenty of ideas but we need more info. I have EFI on mine also but gives us some more input. Was your alternator performing adequately?

 

nothing at all, won’t turn over

 

Do the headlights and other electronics work?

 

headlights were going up and down even without pulling the ****. Forgot to mention with everything there was no engine overheating/engine light on.

 

Do any of your electrical loads work at all? Not what was happening before but what is happening now.
Can you rotate the engine by hand? If so, then just try jump-starting it..... if it starts then we can check other things. If it turns over but does not start then we can check other things.

This is a big leap --- but if your alternator was not performing adequately and you've been running on the battery then you could have just used up the battery..... I'm just throwing that out there....go do the checks to see if it will turn over when jumped.

 

electrical loads seemed to be working properly the whole time. Car is completely dead now so I need to replace or jump

 

but even if the alternator went bad and the the battery just ran dead that wouldn’t cause the engine to just stop running while driving it?

 

Once your battery goes below a certain level nothing will work appropriately. So, YES, the car will work half-assedly until their is insufficient power to support the system.... you have EFI and an Electric Fuel Pump so at a certain point things just stop working. If you alternator was not keeping the battery appropriately charged then you were using the battery up .... not biggie. Lots of methods to check that.
I suspect your battery is dead. It probably needs a charge so you can just take it out and down to autozone and they'll do a free load test. MEANWHILE, you can try doing a jump before you do that but make sure you attach the jumpers cables appropriately and let the supply vehicle supply for a couple of minutes before trying to turn over.

 

Tell us about your car to check how the charging system was set up on that thing. Take some close up pics of the alternator and it's connections and see if there is any info stamped/written/etched on it.

 

What kind of fuel pressure is in the system? Have you tried to test the fuel pump relay? I would manually send 12 Vdc to the fuel pump and see if it is working. It also sounds like a fuel filter getting plugged up....

Maybe I am missing something but what year is this Corvette that you are speaking about? Early 1980's? Crossfire engine or what? The Profile section above is designed for us to enter the basic information regarding our Corvette. It would be really helpful if that was filled out as I am shooting in the dark.

When I hear an engine "seized", that tells me that it locked up. "Seized up" is frequently a catastrophic failure of internal parts of the engine causing it to stop rotating.

Take a good multi-meter and verify the battery voltage. Then take the meter and verify the voltage at the Fuse for the electric Fuel Pump. If they are different by a substantial amount then you might have corrosion in the electrical system. I used my Power Probe and powered the fuel pump at the fuel pump's harness and it worked, the factory wiring was supplying less than 10 volts which kept the pump from even starting to spin up. It turned out to be the power coming from the fusible links that power the entire car and engine had corrosion on the surface which lead to a low voltage situation at the fuel pump even though the battery voltage was still above 12 Volts. Just a thought....

 

Didn’t start when hooked up to jump. I believe I need to remove this plate to access the alternator numbers

 

sorry I didn’t mean seized up but rather shut off while driving. It’s a 82’ crossfire but all engine block and fuel injection has been replaced so doesn’t have the OEM crossfire engine/fuel injection

 

Alternator looks like it has the generic 12si connector on the side so probably stock to an 82. No need to take anything else apart. We can improve on that once we figure what's going on with the engine.

 

What engine is in the car as it is today? Are you running an EFI system or switched back to a carburetor? If you have an HEI distributor then it is possible that your "Module" has failed. The module is the brains of the HEI and it requires new Thermal Paste and a clean surface to make the parts work. They can start misfiring as you described and this leads to a total shut-down pretty soon after. With the many years they made HEI distributors there are several different modules for this distributor body. HEI's will Can and Will, work Great, if, they are maintained and kept clean. Unfortunately they have some problems with the modules failing and there are so many different modules for different uses.
In my 1988 Corvette I have an HEI distributor so I keep a spare module inside the car. It is wrapped and stashed "just-in-case".

If you have a "Points" Type Distributor ignition coil and points type distributor I would venture a guess towards the ignition coil starting to get old.

Check your battery's connection. If your battery connections get corroded they NEED to be cleaned. Measure the voltage at the battery and measure the voltage at the alternator output. They should be the same number or very, very close.

What did they do to your Fuel pump system? Did they go mechanical or try to use what they came with?

I apologize for hitting you with the questions, the more information we have the easier it will be for us here at the Corvette Forum to solve. The more you tell us about your Corvette and the engine in it, the easier it gets solving the issue.
There are a lot of extremely knowledgeable people on the Corvette Forum.

 

I don’t mind the questions at all! I try and give all the answers I can but sometimes I don’t have them as the car I bought from the previous owner he didn’t really have any knowledge of the car. He just paid for the install of parts because people probably “told” him to. It has a 383 stroker crate engine and a Mass Flo fuel injection system. Which from research I believe Mass Flo isn’t their name anymore. I believe it’s Pro M or something like that. Has a Mallory fuel pressure regulator and an automotive stealth electric fuel pump..

 

Here’s an update of what happens now when trying to start after charging the battery..