HELP Holley super Sniper 4 bbl woes, 502 ci big Block

[Vbb199]

I've read time and time again, if you put the trigger wire for the efi anywhere that has a slight drop in voltage during cranking, it'll have a tendency to drop out voltage to the ECM.

This evening, along with the many many things I have to do on it, as a test, I'm gonna tie the trigger directly to the battery, just as a constant voltage source, and see if it fires up.

 

[Vbb199]

But does the distributor get full 12v while cranking? Or efi controls it?

Dizzy gets a full 12v, I was able to confirm that with my multimeter.

 

[Vbb199]

Efi does not control timing.

It's a basic GM HEI distributor.

 

[SquareRoot]

@SquareRoot I currently have the efi's pink trigger wire running to the "iginiton" source on my fuse block.

Not every ignition port is hot while cranking. That's the mistake I made. Whatever circuit feeds your HEI positive will be hot while cranking.

I have a schematic at home that helped me understand it. But, I actually found it by using a test light. Stick the probe in each fuse holder and crank the key until you find one that stays hot in crank.

For now, just connect the pink to battery to see if it will start to rule out the easy fix.

 

[Vbb199]

Not every ignition port is hot while cranking. That's the mistake I made. Whatever circuit feeds your HEI positive will be hot while cranking.

I have a schematic at home that helped me understand it. But, I actually found it by using a test light. Stick the probe in each fuse holder and crank the key until you find one that stays hot in crank.

For now, just connect the pink to battery to see if it will start to rule out the easy fix.

Yesterday, I put my multimeter in the "iginiton" port on the fuse block (same one I've been using)

Turned key on, got 12v.

Cranked, it dropped a little... Like to 10 volts?

I'm beginning to wonder if I need a relay from the battery that'll just constantly keep that thing energized with key on.

But I will add however, that big mf of a motor does draw some voltage even on that new deep cycle marine battery I have in there.

 

[Vbb199]

I suppose if worse comes to worse, a capacitor could be added. It'll store a constant 12v supply just for the efi. So no matter how much that bastard of a motor pulls on the battery, there's still a nice stored 12v always available for cranking for the efi.

 

[SquareRoot]

Keep in mind, everytime you cycle the key, the POS....I mean Sniper, gives a shot of fuel prime down the manifold whether it fires or not. Yes, you can foul the plugs without it ever running for any length of time. I did it. Also, it would occasionally start when I let OFF the key from cranking and for a split second it got 12 volts and caught before the engine stopped spinning.

She was a finicky little bitch!

 

[Vbb199]

Keep in mind, everytime you cycle the key, the POS....I mean Sniper, gives a shot of fuel prime down the manifold whether it fires or not. Yes, you can foul the plugs without it ever running for any length of time. I did it. Also, it would occasionally start when I let OFF the key from cranking and for a split second it got 12 volts and caught before the engine stopped spinning.

She was a finicky little bitch!

That's what's happening now...

I can crank on it for a bit, if I let off, occasionally it'll try to fire...

And for the people swearing up and down its 180 off... (this just came to mind)
After I set timing myself, I had the rotor pointed JUST BEFORE #1's tower on the dizzy.... Setup everything, cycled the key to prime it with a little fuel, I BUMPED the ignition and damn thing started to run, and died out shortly after... From what it sounded like, I got fire on all 8 cylinders, but something quit, because it spit afterwards.

I find it hard to believe its just way out of timing.

It's something gay like plug wires, or voltage drops in the efi.

 

[SquareRoot]

I suppose if worse comes to worse, a capacitor could be added. It'll store a constant 12v supply just for the efi. So no matter how much that bastard of a motor pulls on the battery, there's still a nice stored 12v always available for cranking for the efi.

This was the rabbit hole many of us went down. We ended changing and adding **** to our vehicles to support the Sniper. EMI is a huge problem so order your MSD Super Conductor plug wires now. I hope your running an automatic transmission? I won't even start about the ****** throttle linkage geometry or the IAC trying to hold a steady idle.

Ok, I won't bash it anymore on this thread. Only helpful helpful advice going forward.

 

[SquareRoot]

No gay plug wires here. Manly man wires.

You must be registered for see images attach

 

[Vbb199]

No gay plug wires here. Manly man wires.

You must be registered for see images attach

I have genuine GM performance plugs.
But they've sat in the elements under the hood for over 2 years. And as I said, I discovered a crack in #6's plug wire.

Ironically the same cylinder that had a sparkplug with raw gas on it.

And yes, I'm running an automatic transmission. 2wd th400

 

[Vbb199]

Given this wealth of knowledge. After work, I'm gonna firstly check my plug wires again.

I have some others I can try for now if they're all cracked and damaged.

Following that, I'm gonna tie the efi direct to the battery.

Lastly, I'm gonna try to crank it.

If it still don't run..........


As an added bonus, I might open the throttle plate and take a dump in the intake.

 

[Vbb199]

I wanna add as well, there was a time (or two)

I was able to barely keep it running by very very lightly feathering the gas pedal, but it spit back at me afterwards, and that was also before I got a GOOD battery, and reset the timing myself.

 

[SquareRoot]

Well hopefully it don't spit back at you while you're taking a dump down the intake. If so, please post pics!

 

[Vbb199]

Well hopefully it don't spit back at you while you're taking a dump down the intake. If so, please post pics!

You're one of them guys that eats your hotdogs burnt. Aren't ya? Sicko.

Hey man, seriously, I do appreciate the info.

I'm gonna give it a few good stabs this evening, maybe I won't come up so empty handed.
But if I do, hit that "watch thread" button in case... Because I might be back ranting.