My 350 shutting off while driving

[Grit dog]

I doubt any of the things you mentioned are the cause of random stalling.
And likely not contributing causes if it generally runs fine otherwise.
Overfull oil is an issue unless it was just over filled, presuming you don’t know what the previous oil level was.
Assume it’s still a TBI engine since you asked about fuel pump relay.
As both ignition and fuel are electronically controlled the likely problem is an electrical short “somewhere “ between the ignition switch on the column and the final destination (ign module, coil, fuel pump, injectors).
Equally likely it’s a bad or intermittent ground in one of several locations.

Tough part is finding a local shop who is honest and has a mechanic that can do actual physical diagnosis without a code reader and computer.

Given your level of knowledge, I’d first check and clean every ground you can find. If that don’t work, the decision tree gets several more branches.
Although if you can pinpoint whether it’s spark or fuel that’s half the battle.
If it starts right back up, that is tougher. If it dies and won’t restart for a bit it’s much easier to check spark or fuel.

Good luck!

 

[Kurnacopia]

Hi Hugo. I am IT guy and have been for years. I am also a Squarebody guy since the 80s. I believe in one very important phrase taught to me by a very smart man: "what changed?" If the truck ran perfectly before the fix, logic kinda dictates something the guy touched when doing the work is most likely the culprit. An engine that just "shuts down" is very vague and more input is kinda needed and what the mechanic did would be helpful. But, start thinking about what comes out and goes back in when he did the work. Lines can be cut. Wires bent or broke. Parts can be mysteriously replaced. Think outside the box and track down the small things first. Rule them out then then move on to the larger things. Think outside the box. Some say to take it to a mechanic...and its good advice, but some of us don't have the cash nor the time for that. Best of luck my friend.

 

[Don-T]

If it will start and run you can try wiggling wires a bit to see if it quits. Don’t go pulling on them hard enough to break them and don’t mess with the secondary ignition wires, they will bite. I would try the wiring on the firewall and near the back of the engine where the mechanic may have been. I had an issue with a small block Chevy I put in a Jeep shutting down from time to time with no warning. That was how I stumbled onto my problem, the 12 volt wire going to the HEI distributer had a break in the conductor but the insulator looked ok. After that fix it never shut down without a warning again.

 

[Ricko1966]

Did you turn it off and turn it back on? Sorry thats how you fix computers.

 

[peats]

I would check the wires at the starter solenoid. power comes from there and the starter was out recently

 

[Grit dog]

I would check the wires at the starter solenoid. power comes from there and the starter was out recently

What he and @Kurnacopia said. Start with what has been messed with recently.

And OP provide more details on what the symptoms are. You were very vague in your first post and then went straight to the what ifs.

the whole truck shut off completley a couple times while driving yesterday

^This could happen with a half dozen different symptoms... cough and sputter, or just off like a light switch. Lose ALL electrical power or just ignition or spark. Instant restart and on your way, or something else. Happen when hitting a bump or not. Died when come to a stop or while driving at speed?

 

[Hugomartin]

What he and @Kurnacopia said. Start with what has been messed with recently.

And OP provide more details on what the symptoms are. You were very vague in your first post and then went straight to the what ifs.


^This could happen with a half dozen different symptoms... cough and sputter, or just off like a light switch. Lose ALL electrical power or just ignition or spark. Instant restart and on your way, or something else. Happen when hitting a bump or not. Died when come to a stop or while driving at speed?

Yes to stopping at driving speed and at a stop. Died completely no lights no power steering as if a ghost turned the key to off.... So maybe it is ignition wire lose....... Took a few tries of cranking to get it to start also like 15 second cranks

 

[Grit dog]

Yes to stopping at driving speed and at a stop. Died completely no lights no power steering as if a ghost turned the key to off.... So maybe it is ignition wire lose....... Took a few tries of cranking to get it to start also like 15 second cranks

Power steering is a function of the engine turning, nothing electrical, same with power brakes.
Lights shut off means loss of power, but lights stay on even with ignition switch off and a short or issue with the ignition coil or even the ignition switch or wiring shouldn't also exhibit lights turning off.
Plus it re-cranked immediately. (Taking a bit to crank if it lost spark and dumped a little fuel creating a semi flooded condition also seems not a likely part of the equation.)
This honestly sounds most likely a short or loss of power from the + wire coming from the starter to the fusible link on the firewall that feeds all the electrical loads in the truck.
Back to what was messed with, the starter, could have created a short in that wire. That's relatively easy to bypass quickly with a new wire to the fusible link/junction block on the firewall. Can even pull it off the battery and not get under the truck. If it cures the intermittent electrical power loss, you found it.

 

[Hugomartin]

Power steering is a function of the engine turning, nothing electrical, same with power brakes.
Lights shut off means loss of power, but lights stay on even with ignition switch off and a short or issue with the ignition coil or even the ignition switch or wiring shouldn't also exhibit lights turning off.
Plus it re-cranked immediately. (Taking a bit to crank if it lost spark and dumped a little fuel creating a semi flooded condition also seems not a likely part of the equation.)
This honestly sounds most likely a short or loss of power from the + wire coming from the starter to the fusible link on the firewall that feeds all the electrical loads in the truck.
Back to what was messed with, the starter, could have created a short in that wire. That's relatively easy to bypass quickly with a new wire to the fusible link/junction block on the firewall. Can even pull it off the battery and not get under the truck. If it cures the intermittent electrical power loss, you found it.

 

[Hugomartin]

Power steering is a function of the engine turning, nothing electrical, same with power brakes.
Lights shut off means loss of power, but lights stay on even with ignition switch off and a short or issue with the ignition coil or even the ignition switch or wiring shouldn't also exhibit lights turning off.
Plus it re-cranked immediately. (Taking a bit to crank if it lost spark and dumped a little fuel creating a semi flooded condition also seems not a likely part of the equation.)
This honestly sounds most likely a short or loss of power from the + wire coming from the starter to the fusible link on the firewall that feeds all the electrical loads in the truck.
Back to what was messed with, the starter, could have created a short in that wire. That's relatively easy to bypass quickly with a new wire to the fusible link/junction block on the firewall. Can even pull it off the battery and not get under the truck. If it cures the intermittent electrical power loss, you found it.

Isnt the ignition control module on the steering collum ?so key to icm to starter then to ignition coil...... A chevy map is needed lol

 

[Hugomartin]

i beleive the icm module going bad , i think i will try to change that out first , then i wil try grit dogs suggestion of a new + wire from the starter

 

[Grit dog]

Well, your lights wouldn't go out if it was the ICM...

 

[Hugomartin]

Well, your lights wouldn't go out if it was the ICM...

I might be mistaken... The whole vehicle died twice perhaps the lights were on, dont know for sure.

Power steering is a function of the engine turning, nothing electrical, same with power brakes.
Lights shut off means loss of power, but lights stay on even with ignition switch off and a short or issue with the ignition coil or even the ignition switch or wiring shouldn't also exhibit lights turning off.
Plus it re-cranked immediately. (Taking a bit to crank if it lost spark and dumped a little fuel creating a semi flooded condition also seems not a likely part of the equation.)
This honestly sounds most likely a short or loss of power from the + wire coming from the starter to the fusible link on the firewall that feeds all the electrical loads in the truck.
Back to what was messed with, the starter, could have created a short in that wire. That's relatively easy to bypass quickly with a new wire to the fusible link/junction block on the firewall. Can even pull it off the battery and not get under the truck. If it cures the intermittent electrical power loss, you found it.

Could i just put on some romex 12 gauge wire from the starter to fuseable link?

 

[Grit dog]

I might be mistaken... The whole vehicle died twice perhaps the lights were on, dont know for sure.

Could i just put on some romex 12 gauge wire from the starter to fuseable link?

To test it, yes. You can run it from the battery as well, to test it. It just pulls from the always hot lead (big wire) on the starter, idk why.
Easy test especially if it’s somewhat predictably dying on you.
Otherwise you’re probably on the right track, icm, ignition switch or just a short in wiring to the icm or distributor if you’re just losing spark.
Good luck with troubleshooting it.

 

[Hugomartin]

Well, your lights wouldn't go out if it was the ICM...

I mispoke everything shut off while driving except lights sorry... Im now took out the two bolts that holed the steering wheel up but i need to research how to gingerly lower the steering wheel , feels like a game of jenga if i dont do this right