no start issue resolution

[ehummelman]

I'm not sure if this should go here or in electrical, but I wanted to post it for anyone that may need another possible answer when searching.
I was having the typical "sometimes it starts and runs, then won't start again" problem. I found at least 15-20 different scenarios others have chased down as causing this. Since my resolution was different than the others (as far as I could tell from reading) I wanted to offer it to the Search archive.

My scenario was this:
Sometimes start no problem, other times just crank away but no fire. Often it seemed like it had the no fire situation after running for a while (as it turns out this was my imagination, or at least not the central issue).
When it would not fire, it always had the proper voltage everywhere (battery, starter solenoid coil, MSD, etc.). The starter always spun too, whereas a lot of others had the click but no spin or just a dead nothing with the key in start.
I had good fuel to the carb squirters.
Once running, I didn't have any erratic issues like misfires, detonation, surging, unexpected dying.



As I said, usually at least one oor a combination of these symptoms was found in all the other threads I read, so obvioulsy I was stumped at first. This morning, I got a lucky break and got the engine to fire, and I got it warmed up so I could let it idle and get under the hood. I started with the easiest thing - look at wiring connections. I just started grabbing and jiggling all the ignition-related wiring to see if anything was loose, frayed, etc. When I jiggled the magnetic pickup wires from the MSD box to the HEI (purple and green) it made some weird electrical whiny noises. I knew that was it. So, took apart the HEI and cleaned up the spade connections for these 2 wires, a dab of dielectric grease and buttoned it all back up. Problem solved, at least for now. I know better than to think the electrical gremlin that lives in my car will not find another way to piss me off.

[ehummelman]

I should add another thing I found last week. After fixing the problem above, I got the same crank but no start problem. Believe me, I let out quite a few choice words. I went under the hood and immediately started the "jiggle" method. This time the culprit was one of the wires coming out of the firewall side fusebox plug. I can't remember which color it was, red or pink I think. I didn't know that these were just spade connectors pushed into the big rubber block. The damn thing just slides right out and must have been loose from my previous jiggling attempts. I can't believe how half-assed the factory setup was. This thing is definitely due for a full on wiring job. I just need to get my Bronco on the road again so the Firebird can hit the shop for a while.

[David Pozzi]

The firewall plug wires snap in & lock, & shouldn't pull out withou releasing the prong on the other side.
Another tip on HEI distributors is the module grounds at the screw nearest the power connector. I had one with stripped threads that came slightly loose & caused an intermittent start issue.

[ehummelman]

Yeah, mine are apparently not locking right. Hence the decision to redo the whole deal when I can have the car down for a while.

[DarkoNova]

I don't remember what kind of terminal ends were used on the firewall plug, but if it's the weird looking ones with the angled slot in it (the terminal itself looks like a weird upside down J), it may be because it got compressed. The slot is the part that locks the terminal in the plug, so just opening the gap a little should make it snap in and stay in place.