Truck keeps cutting off! - The 1947 - Present Chevrolet & GMC Truck Message Board Network

drillrod · 06-25-2022, 05:25 PM

My 72 chevy truck with 350 engine will start and run perfect for about a mile and then cut off just like you switched it off with the key. it wont start back up right then. Go back to it several hours later and it will start right up and go another mile or so. What is wrong? Acts like something is getting hot and has to cool down before it will start again.

**Steeveedee** · 06-25-2022, 05:33 PM

That's usually a loose connection. Wiggle all the connectors in the ignition circuit when it's running (in your driveway) until you fine the culprit. That includes the harness that runs to the fuse block.

mikeshome · 06-25-2022, 06:40 PM

Need a little more info. What does it do when it shuts off? Crank but no start or no power at all? If no power check all battery connections and grounds. If it cranks look it carb when moving throttle is there fuel ?

72c20customcamper · 06-25-2022, 08:20 PM

HEI ? If so check the coil

**Fbks_Cruiser** · 06-25-2022, 08:54 PM

Mine with hei did that exact same thing. Turned out to be a bad module. Switched to the “old” one that was in the glove box. That was 2 years ago. No problems since.

**dagnabbitt** · 06-25-2022, 11:00 PM

Quote:

Originally Posted by Fbks_Cruiser

Mine with hei did that exact same thing. Turned out to be a bad module. Switched to the “old” one that was in the glove box. That was 2 years ago. No problems since.

This gets my vote, and it’s the easiest thing to try first.

**tjc** · 06-25-2022, 09:36 PM

if you are running Pertronix and the wrong coil or a resistor wire, it will do the same thing.

72SB · 06-26-2022, 10:07 AM

Your Pertronix module requires a full 12v. If your stock dizzy was a points dizzy then you need to remove, bypass the stock resistance wire and install a copper braided 12 gauge wire.

Pertronix has instructions in their kits how to do this.

If the resistance wire has been bypassed then either the Pertronix module and or coil is bad. Problem usually shows up once motor gets to operating temp. Use heat sink paste under module when replacing. Most auto part stores have it for $2. Not dialectic grease, heat sink paste is what yu want

rockyrivermark · 06-26-2022, 04:31 PM

Next time it won’t start throw a timing light on it to verify you don’t have spark. No spark is likely the issue but as simple a test as you can do.
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06-25-2022, 05:25 PM	#1
drillrod Registered User Join Date: May 2014 Location: Rose Hill NC Posts: 193	Truck keeps cutting off! My 72 chevy truck with 350 engine will start and run perfect for about a mile and then cut off just like you switched it off with the key. it wont start back up right then. Go back to it several hours later and it will start right up and go another mile or so. What is wrong? Acts like something is getting hot and has to cool down before it will start again.

06-25-2022, 05:33 PM	#2
Steeveedee Who Changed This? Join Date: Jan 2013 Location: Simi Valley, CA Posts: 10,676	Re: Truck keeps cutting off! That's usually a loose connection. Wiggle all the connectors in the ignition circuit when it's running (in your driveway) until you fine the culprit. That includes the harness that runs to the fuse block. __________________ ~Steven '70 Chevy 3/4T Longhorn CST 402/400/3.56 Custom Camper Simi Valley, CA

06-25-2022, 06:40 PM	#3
mikeshome Registered User Join Date: Jul 2013 Location: Mount Albert.Ontario Posts: 119	Re: Truck keeps cutting off! Need a little more info. What does it do when it shuts off? Crank but no start or no power at all? If no power check all battery connections and grounds. If it cranks look it carb when moving throttle is there fuel ?

06-25-2022, 08:20 PM	#4
72c20customcamper Registered User Join Date: Jul 2018 Location: Catskill Mountains,NY Posts: 8,716	Re: Truck keeps cutting off! HEI ? If so check the coil __________________ Mark 72 c20 custom camper Husky edition, 66 SS396 Chevelle 1964 Hawk, 63 Avanti,62 lark 1969 AMX , 1968 c20 stepside ,85 K20 1977 Suburban sold 68 anniversary.

06-25-2022, 08:54 PM	#5
Fbks_Cruiser Senior Member Join Date: Apr 2016 Location: Fairbanks, AK Posts: 343	Re: Truck keeps cutting off! Mine with hei did that exact same thing. Turned out to be a bad module. Switched to the “old” one that was in the glove box. That was 2 years ago. No problems since. __________________ 1972 GMC K2500 Super Custom Matt

06-25-2022, 09:36 PM	#7
tjc Senior Member Join Date: Jun 2011 Location: burlington,iowa Posts: 439	Re: Truck keeps cutting off! if you are running Pertronix and the wrong coil or a resistor wire, it will do the same thing. __________________ Tom in Iowa 68 L88 C10 68 4x4 C10 soon

06-26-2022, 10:07 AM	#8
72SB Registered User Join Date: Apr 2022 Location: Moorpark, CA Posts: 774	Re: Truck keeps cutting off! Your Pertronix module requires a full 12v. If your stock dizzy was a points dizzy then you need to remove, bypass the stock resistance wire and install a copper braided 12 gauge wire. Pertronix has instructions in their kits how to do this. If the resistance wire has been bypassed then either the Pertronix module and or coil is bad. Problem usually shows up once motor gets to operating temp. Use heat sink paste under module when replacing. Most auto part stores have it for $2. Not dialectic grease, heat sink paste is what yu want

06-26-2022, 04:31 PM	#9
rockyrivermark Registered User Join Date: Apr 2011 Location: Fairview Park, Ohio Posts: 1,031	Re: Truck keeps cutting off! Next time it won’t start throw a timing light on it to verify you don’t have spark. No spark is likely the issue but as simple a test as you can do. Posted via Mobile Device



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