No start 84 crossfire

[Walter F.]

For the last eight years my 84 Corvette get a no start condition. This happens about every 75 to 100 starts. I only drive this car about 1500-2000 miles a year. When this no start condition exists I have no spark. The fuel pump seems to be working as I hear it hum. What makes this so crazy,this problem is corrected by unscrewing the distributor cap, lifting it up and screwing it back down. When I do this the cars starts right up every time and will be good for another 75-100 starts? I have changed many rotors, the cap and the coil. No change?

[Ed H.]

Re: No start 84 crossfire

Walter, this model, with the optispark system, suffers from condensation or water vapor getting into the dist. There is a fix that is advertised in Corvette Central, Paragon and Ecklers. I do not know what the fix is or the cost. Maybe some other members who have suffered from this problem will answer up. Good luck.

[Terry M.]

Re: No start 84 crossfire

Walter, this model, with the optispark system, suffers from condensation or water vapor getting into the dist. There is a fix that is advertised in Corvette Central, Paragon and Ecklers. I do not know what the fix is or the cost. Maybe some other members who have suffered from this problem will answer up. Good luck.

Ed
I am pretty sure the optispark started in 1992. The OP has a 1984 that has an HEI ignition system. I would check the low voltage connections to the coil that is on the top of the distributor cap.

[Ed H.]

Re: No start 84 crossfire

Your right Terry, I think I read it as a 94, this must be age related. My 90 had HEI, dyslectic I guess.

[Mark E.]

Re: No start 84 crossfire

Walter,

Intermittent problems can be challenging to diagnosis.

Ideally, next time the problem will happen in your garage so you can systematically run down root cause. As Terry suggests, check primary voltage. No voltage points to an electrical open in the ignition switch circuit. Common culprits are the neutral safety switch (auto) or clutch safety switch. Also check VATS- will it start after it times out (5 minutes? Check the manual) or if using a different key?

If you do have primary voltage, then look at HEI components in the distributor, including the module, coil and their connections.

Don't forget to keep us posted.

[John D.]

Re: No start 84 crossfire

Walter, My old May 83 car used to do the same thing. I replaced the module and put on a new distributor cap and the problem went away.
I will always miss that car as it was used in the first C4 judging school at a Pittsburgh chapter meet conducted by Tom Barr.
Here's another thing to watch out for. The car sat for a long time and I was very sure it needed a new electric pump.
Well my ex got the car and paid a fortune in repairs to get it started. All it really needed was a new pump.

[Walter F.]

Re: No start 84 crossfire

Just did a test from the FSM for testing the pickup coil inside the distributor. FSM said it should read between 500-1500. Mine reads 716 so that tells me that part is OK. Ill keeping digging.

[Chris G.]

Re: No start 84 crossfire

yeah, should be a straight forward diagnostic. Coil is where I would start.

[Walter F.]

Re: No start 84 crossfire

The coil is brand new. I replaced the MSD coil with the stock one. That is what I though was the original problem. No change. And I do not feel any difference in performance with the stock coil and wires as the MSD set up the other owner had on the car.

[Mark E.]

Re: No start 84 crossfire

During situations like this, I ask myself: Is this an opportunity to practice my diagnostic abilities? Or do I just want to fix it quickly?

If the latter, consider buying and installing a complete new distributor- cap, rotor, module, coil... everything. About $100 from FLAPS. This will either fix the problem, or worst case, eliminate the distributor and its components as the problem.

And bonus: You now have a spare distributor for future troubleshooting, quick repairs, and trying new timing advance maps.

[Walter F.]

Re: No start 84 crossfire

I was thinking about that, but another Corvette owner made a suggestion. He asked if I used dieelectric grease after I replaced the module. Since I do not remember I think this is worth a shot and have a look, especially since this always happens on a hot engine.

[Mark E.]

Re: No start 84 crossfire

You may get lucky by guessing root cause, but that doesn't often lead to rapid resolution.

[Walter F.]

Re: No start 84 crossfire

I removed the module today and cleaned off what seemed to be some sort of grease which was white in color. I put dieelectric grease on the module and reinstalled it. If that does not work I will just replace the whole distributor.