Recap of ongoing problem: Hoping for expertise?

[Bilgamesh]

I have a recently rebuilt 302. It has a pertronix ignitor, reman Motorcraft 2150 carb, and otherwise stock. It runs well at idle. When it gets warmed up at highway speed, it suddenly dies. Sometimes it will rev back up, sometimes it will backfire too. It will always turn over afterward. It normally does not act up unless I get back up to speed, but sometimes after it starts acting up, it will die at lower speeds. I cannot tell what is going on. I have replaced the coil, fuel pump, fuel filters, carb, swapped in points, new vacuum cannister, reset timing to anywhere from 6-12 btc, tried larger carb jets, running without gas cap, blah blah blah. My vacuum is good at 19". Still the same problem. I have also checked the float on the carb dry and wet. I have double-checked firing order. I have not replaced the distributor or the wires. Is there anything else anyone can think of? Could a restricted exhaust cause this? How about a clogged breather? My pipes and mufflers are really rusty... I am at wits end with it. I would appreciate any new ideas. -Thanks

 

[ballistic64]

Crap in the fuel tank or fuel selector valve?

 

[Bilgamesh]

I have a single fuel tank, recently sealed with Red-Kote. I also have a clear fuel filter that remains full and clear throughout my adventure. - Thanks

 

[FASTERDAMITT]

Here's a tip. An electrical connection can be fine until a heavy load is applied. At that time the load across the minute area of continuity will be to much to supply enough power to the device on the other end. Therefore either shutting down briefly to cool slightly or causing intermitent power loads across the bad connection. This can be unseen as corrosion inside a cable also. Check or replace everything from the battery post to the ignition. I had been in your shoes for weeks before I discovered a connection like this. Good luck.
Tom

 

[Bilgamesh]

Yes, the wiring thing had occurred to me. I have done a quick cursory check of the wires and not turned up much, but I will dig in deeper.

Keep the ideas coming...

Thanks

 

[TOFIC]

check the wiring very carefully. I had this problem with a 55 Ch**y. After much fighting I took it to a auto electric shop and they found the problem in 5 minutes. A wire in the distributor was broken inside the insulation. When the motor spooled up and the distributor advanced it pulled slightly on the wire and separated the connection. engine stopped distributor went back to normal position and the wire "reconnected" engine started. replaced 4 feet of wire and no more problem.
TOFIC

 

[72Sport]

I had a similar problem with a Pertronix which was caused by a bad rebuilt vacuum advance. There was no stop or adjustment in the vacuum advance. The total advance was 57 degrees. The excess advance pulled the red wire out of the pickup in the distributor. It did not break the insulation on the red wire only the conductors. Fortunately I live near Pertronix so I took it too them and they found the problem. Try putting the points back in and see if the problem goes away. I am not sure how you would check it with possibly breaking the unit.

Same scenario as mentioned by TOFIC.

 

[Bilgamesh]

Thanks for the feedback. I know my original message lacked a sense of organization, but I did say I had already swapped points back in. The only other wire in the distributor is the ground wire, which is sound. I had also swapped in a new vacuum cannister and set total timing with a light, to no effect.

 

[OX1]

I agree on checking out all the wiring. Could be not broken internaly, but corroded to crap wires that work just good enough at lower amperage draws. I sure would replace spark plug wires too. A million times over I've seen them make engines act all kinds of weird under load.........

 

[Bilgamesh]

Does anyone know what this is? :

http://www.bilgamesh.com/CorrodedPlug.JPG

I found it near the passenger firewall with two black wires and a yellow or green one with a red stripe. It was so badly corroded it fell apart in my hands. I know one wire from it went to the alternator. Maybe this will give me some help. - Thanks

 

[Bilgamesh]

STRIKE UP THE BAND FELLAS! That corroded plug was the source of my problem. I spliced the wires and started her up. Though it was a little cold this morning to go topless, I went for it. I drove for 15 minutes at highway speed with no problem. I have almost 500 mi. on the new engine now, so I just need to fine tune the carb, timing etc. Thanks to everyone who took teh time to give me feedback and support. I hope to repay by reciprocating when I have something of value to add. -Best Regards