Ignition Problems

[B Neal]

I have 1965 GTO, the motor is a 1969 400, it has an after market HEI Distributor. The car was running fine. Over the last few months I installed an vintage air system. some gages under the dash and a few other goodies, like aluminum pulleys. Got it ready to start the car started but wouldn't run, got to the point were it wouldn't even try to start,  checked things out found had no spark.  Ordered a new MSD cap, rotor, and ignition module.  Put it in and again it tried to start put wouldn't stay running, then again I lost spark.  Not wanting to wait for another MSD module I went to O Reilly's and bought a Accel Ignition module. Put it in it started right up, ran fine.  Went out Today after setting for about a week tried to start it NO SPARK.   I really hate electrical problems.  Any one got ant ideas as to what the problem could be

[Frosty]

Here is a pretty good HEI diagnosis article that might help.

https://www.chevyhardcore.com/news/hei-distributor-troubleshooting-with-performance-distributors/

 

Here is YouTube video on the same subject.

 

 

Edited April 12, 2021 by Frosty

[B Neal]

Thanks that Video pretty basic, I know to check all of what he is showing. My problem is more complicated than that. I all ready have all new parts. But something is burning out the ignition modules, Need to find out what 

[Fitzy]

Like you Neal, I also scratch my head when it comes to electrics. All I could think of was if you have some sort of fusible link or circuit breaker that's either blowing or tripping? Is the ignition module internally fused? Any sort of rust, dirt or compromised surface on any connection will create resistance that can lead to all sorts of problems. Someone recently posted that where the distributor base abuts the block, that's actually an earth. Is that all good?

I'm a bit of a sook. I'll have a go trying to fix something but if it keeps beating me, I don't keep smashing my head against the wall - I take it to a professional!

[TWO LANE BLACK TOP]

This may sound crazy....Are all the metal ends on the spark plug wire ends pushed all the way down and tightly fit the contacts on the distributor cap and the plugs....???

It's possible for the rubber boots to be bottomed out but the wire ends not be directly contacting the plugs/distributor cap...Causing the spark to have to jump a gap between the wire ends and the plugs/distributor cap contacts...car would run OK...Because the spark would be insulated inside the rubber boot and not short against anything metal...But If the spark has to jump a gap between the wire ends and the contacts...It will cause the ignition module to internally overheat and prematurely fail...Because of the extra energy needed to jump any gaps that may be created by the wires not tightly connected to the plugs/distributor.....

[Frosty]

Most modules go bad because of heat. I will suggest some more obscure items:

1. AC voltage spikes from your alternator, try looking across the diode assembly to see if your current or voltage is spiking.

2. Possible ground issue? Although by now you probably have looked at that

3. I read on a rare occasion, as the distributor ages and wears, the bushing in the distributor shaft goes bad and starts to cause excessive heat. The heat travels up the housing to the bottom plate of the distributor and cooks the module.

4. If you HEI distributor still has a condenser, try replacing it, it maybe bad.

Edited April 13, 2021 by Frosty

[JUSTA6]

Contact the manufacturer, they have prob solving tech's ready to try N help.  I switched out my Mallory duel point to their light trigger module.  $115.00 for each module. Went through them like candy.  Mallory suggested a plug in module on the outside of the distributor. (forget the name, but like a resetable fuse)  Didn't help anyways.  They ended up refunding my money for the module and sent back all the burned out light triggers which they replaced with new.  Never did anything else to the car and problem has not been a factor since.  Bad batch of light triggers???  

[64 kiwi boni]

18 hours ago, Frosty said:

. AC voltage spikes from your alternator, try looking across the diode assembly to see if your current or voltage is spiking.

This was my thought ! check your alternator to ensure your not sending out too many volts🙄

[B Neal]

Thanks every one. I ordered new parts, be here tomorrow. Going out of town for the weekend. wouldn't be working on it again till next week 

[B Neal]

Finally got back to working on the GTO.  It seems that I may have a bigger problem.  Put in the new module and wiring harness,  Got the car started. but it does not want to run right,  set the timing at 10 degrees. Noticed the timing is fluctuating all over the place. I know this can be caused by the timing chain being stretched. but it was running fine before.  Do you think this could be the distributer. It is an after market billet distributor I don't know who made it, it was in the car when I bought it or another reason for the timing to fluctuate, thanks

[Frosty]

The fact that you have fluctuating timing concerns me. Any idea how many miles are on your 400 engine at this point? I am like you, I suspect the timing chain is the problem here.

[B Neal]

I do not, the car has 90,000+, but it is a 1965. the motor checks out to be a 1969 400. It was in the car when I bought it. The thing that has me  confused is that the car was running fine before I put in the vintage air, Then when I got it done the car started having starting problems. went through two ignition modules now on the third one and now the timing is fluctuating.  I am really wondering if it isn't the distributer ( it is an aftermarket HEI unit no name or markings on it).  I am thinking that if the bushings on the shaft are letting it wobble that would mess with the timing.  My real dilemma is that I am thinking about changing over to fuel injection and if I do that I want to change the distributer any way. But I would like to find out for sure if that is the problem.  still researching it.  But I am leaving in two weeks for the summer and wont be able to do any thing on it till we Get back in September.  Don't like spending summers in in Las Vegas to hot

[Frosty]

Well a reputable new HEI distributor can't hurt. If it is your timing chain though, a new distributor won't help it either.

[B Neal]

Your right, I am still working on which way I want to go. It may have to wait till fall when I get back in town.  I am really leaning towards the EFI. And if I go that way I want to go with the Distributor that supports it.  Looking at the spread bore from Holley.