292 random shut down at idle

[East50Nick]

Hey guys, I have a fairly unique issue here. I have a rebuilt 292 straight 6 engine with the summit brand hei distributor in it. New American auto wire harness, New alternator, battery etc. Everything is new. The engine has the lump port kit installed from 12bolt Tom, im running the split headers from 12 bolt Tom and an offenhauser 4 barrel intake with an edlebrock 4 barrel 500 cfm carb. I took the carb and distributor to a local hero amongst the race community around here, Bob with competition carburetion to jet the carb and curve the distributor to match what the engine needs based off of the build. The engine build is like I previous mentioned, lump kit, mild rv cam, over bore of .030 and roller rockers.

The issue I am having is the truck fires up, and runs just fine, and without any notice at all- shuts down. I mean, no notice at all, just shuts it's self off.

We have a fuel gauge in line to monitor pressure, which remains normal. We have jumpered ground from the battery to the distributor, we have jumpered hot to the distributor. Same thing, it shuts off with zero notice at all, and then fires right back up on the first crank.

After off and on troubleshooting for 2 years and replacing the pick up coil, pick up module, and coil to no avail, I took the distributor back to Bob with comp carb here in town. He bench tested it and said everything is working as it should. I brought it back home, installed it- same thing again. Shuts off with no notice and no stumbling sputtering or indications otherwise.

Have any of you ever dealt with something like this? I am at a loss as for what to do at this point.

Thanks for any help in advance.

Nick

[geezer#99]

What’s your fuel pressure?
Does it do it anytime you start it or just first cold fire?
Do you have 12v to the distributor?

[East50Nick]

Fuel pressure is remaining at 6psi, we definitely have 12v to the distributor (still shutting down with positive jumpered to the distributor from the battery) it happens any time. Cold, warm or operating temperature.

[geezer#99]

Do you look inside the carb when it quits? Excess fuel in the plenum might mean too much pressure. The lower the better on an eddy carb. 4-5 psi.
What’s your timing curve like?
How much initial base timing?

[East50Nick]

Sorry for the lapse in reply time here.

The timing curve is hard to tell at this point because the timing is just set for tdc at the moment. We actually may have fixed the problem Saturday evening though. Looking like it was a bad module right out of the box. Kind of frustrating, but still a success. I guess I'll be keeping a couple of those on the shelf for the future. We replaced the pick up module (again, replaced it last year and it never fixed the problem, and the module bench test fine per all the specs we could find on how to bench test it with a meter) and it's running without issue. Running smooth from start up to shut down. We repeated the process 4 times, keeping track of how long we ran it, and two of the times included a short drive down the street and back just to check it under operating conditions other than idle. Thank you for your suggestions, I am still learning as I go with this truck, but your questions sparked some valuable conversations with my dad. I hope you have a great week man, im hoping to be posting more success stories in the future.

[theastronaut]

I've been through a few modules in my '66 in the last year, found out the rectifier in the alternator was killing the modules. Been fine since swapping in a known good used alternator.

The bad alternator was an AC Delco Gold reman that failed to charge at about 12k miles on it.
Pulled it and took it apart- found a rough bearing, a loose ground wire inside, the capacitor was flopping around, and it had a broken wire on a diode. Check your alternator for AC output, supposedly that'll kill HEI modules.

[shp4man]

Yank all that electronic crap out and put the points back in. OK, that may not be the most popular answer, but....