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Discussion Starter · #1 ·
How’s it going I’ve never used a forum before but I have an issue going on with my 1967 mustang, it has a 351w in it and I’ve had issues with it shutting off while under acceleration. I’ll stumble and seems to lose electrical power. I had a 750 Holley on it when this issue started, I already had purchased a Holley sniper EFI kit for it, I thought it was the fuel pressure dropping with my old pump for the carb but after installing the EFI system it still does the same issue. Can it be the kill switch or starter solenoid? Or what else can it be? Thank you for any help I can get.
 

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Loose battery cable, loose ground or connection at the coil or distributor, loose ignition switch components...time to start it and walk around wiggling stuff in the car.
 

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Just some guy
67 coupe, 69 Sportsroof, 86 hatchback
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I'd start with looking to see if it had ignition spark when it quit. Tough if it starts right back up again. Most spark checkers are short and meant to be used while you are under the hood with them. Does it just die and stay dead or does it crank right back up again?
 

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Discussion Starter · #4 ·
Loose battery cable, loose ground or connection at the coil or distributor, loose ignition switch components...time to start it and walk around wiggling stuff in the car.


Ok and also my bad heard a sparking noise over by the starter I need to check that area too and see what that noise was.
 

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Discussion Starter · #5 ·
I put a new ignition system pretty much when I went efi I put a new distributor, cables, spark plugs and the MSD 6al was recently rebuilt by MSD. I’ve tried even just the coil with no box and it still does the same. I don’t think it’s the spark i don’t know but it will sit there and run at idle for like 30mins with nothing wrong.

So when it shuts off I can start it right back up after a couple minutes. It also cranks pretty hard it has trouble cranking over. And my dad said that he can heard like a sparking noise over on the passenger side under the hood like the solenoid or the starter. I also have a kill switch on that side too.
 

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Discussion Starter · #6 ·
I'd start with looking to see if it had ignition spark when it quit. Tough if it starts right back up again. Most spark checkers are short and meant to be used while you are under the hood with them. Does it just die and stay dead or does it crank right back up again?

I put a new ignition system pretty much when I went efi I put a new distributor, cables, spark plugs and the MSD 6al was recently rebuilt by MSD. I’ve tried even just the coil with no box and it still does the same. I don’t think it’s the spark i don’t know but it will sit there and run at idle for like 30mins with nothing wrong.

So when it shuts off I can start it right back up after a couple minutes. It also cranks pretty hard it has trouble cranking over. And my dad said that he can heard like a sparking noise over on the passenger side under the hood like the solenoid or the starter. I also have a kill switch on that side too.
 

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There should be a ground wire from the engine to the firewall over on the passenger side in the back. Make sure that's good.

It's probably worth standing there under the hood looking at it while someone else starts it to see if you can see the sparking. Doing it in the dark should make it even easier to see if you can spot it.

All the big cables are over there on the passenger side. Battery+ to solenoid, solenoid to starter, firewall to engine, and engine to battery-. They probably all need to be cleaned up but they should at least all be looked at.

Since you mentioned it, how does this kill switch plug into everything?
 

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Discussion Starter · #8 ·
There should be a ground wire from the engine to the firewall over on the passenger side in the back. Make sure that's good.

It's probably worth standing there under the hood looking at it while someone else starts it to see if you can see the sparking. Doing it in the dark should make it even easier to see if you can spot it.

All the big cables are over there on the passenger side. Battery+ to solenoid, solenoid to starter, firewall to engine, and engine to battery-. They probably all need to be cleaned up but they should at least all be looked at.

Since you mentioned it, how does this kill switch plug into everything?

Before when I would shut the key off something would still stay on because the battery would always die
 

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Ah, so it's like a battery cut off switch then? That's probably worth checking the connections on it too while you're there.
 
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