Engine shuts off while driving - SOLVED

[sasso]

So, just after 2 hour drive, approaching my parking my engine just shuts off, and i get a message saying restart engine. I go to restart it but it cranks and doesnt start. While waiting for the tow truck, about an hour and a half later the car starts up just fine. I drive around for a but and it shuts off again. get it towed to the dealer and they change battery sensor and do some reprogramming, i drive it out and 10 mins later same thing happens again. Dealership is useless cause they never seem to diagnose the problem when it is happening as on cold start the car starts and runs fine. So i took it back changed the fuel pump control module the next time it shuts off but that didnt seem to fix it. now i have it at an independent garage, anyone have any ideas as what it could be? Im gonna also change the crankshaft position sensor tomorrow.

2023 Yukon SLT 5.3l

 

[blanchard7684]

Any stored codes?

 

[sasso]

Any stored codes?

0 codes, except low battery and that was mainly because trying to start it up drained the battery

 

[blanchard7684]

No codes...wow.

Was the fuel pump module you replaced a 13554821 part number?

based on what is written it could be either a fuel pump intermittently quitting, a loose ground, rodent damage on wiring, or a harness/ major connection issue.

 

[Pressureangle]

Fuel pump. Best guess.
New truck, low miles, Chinese conspiracy.

 

[Joseph Garcia]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

You are already receiving sage advice from the knowledgeable folks on this Forum.

You stated that there are no trouble codes being generated. Are you using a quality bi-directional scanner, one that is capable of interacting with all of the truck's modules (where deeper trouble codes may be stored)?

 

[sasso]

No codes...wow.

Was the fuel pump module you replaced a 13554821 part number?

based on what is written it could be either a fuel pump intermittently quitting, a loose ground, rodent damage on wiring, or a harness/ major connection issue.

Since i suspected the FPCM i did a roadside repair, i replaced it with 13554821 but dunno what the original was as its still on the truck. didnt get around to removing it completely.

Thank you for your advice, gonna check the fuel pump tomorrow, which ground should i check?

He only thing that is confusing is that it happens once it warms up, and every single time on a cold start it will start up normally. baffled.

 

[sasso]

t

Fuel pump. Best guess.
New truck, low miles, Chinese conspiracy.

thanks, will get it replaced. Whats annoying is that i have to get it to the point where it fails to start and then replace it and then see if it starts up. A real pain to drive it around and not knowing when its gonna die and then getting stuck on a road that might cause traffic.

but i know that it usually dies when i slow down. that could be another hint

 

[sasso]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

You are already receiving sage advice from the knowledgeable folks on this Forum.

You stated that there are no trouble codes being generated. Are you using a quality bi-directional scanner, one that is capable of interacting with all of the truck's modules (where deeper trouble codes may be stored)?

Yes, using a quality scanner.

will post pics once i get her back

 

[Doubeleive]

So, just after 2 hour drive, approaching my parking my engine just shuts off, and i get a message saying restart engine. I go to restart it but it cranks and doesnt start. While waiting for the tow truck, about an hour and a half later the car starts up just fine. I drive around for a but and it shuts off again. get it towed to the dealer and they change battery sensor and do some reprogramming, i drive it out and 10 mins later same thing happens again. Dealership is useless cause they never seem to diagnose the problem when it is happening as on cold start the car starts and runs fine. So i took it back changed the fuel pump control module the next time it shuts off but that didnt seem to fix it. now i have it at an independent garage, anyone have any ideas as what it could be? Im gonna also change the crankshaft position sensor tomorrow.

2023 Yukon SLT 5.3l

what you will probably want to do besides a good visual inspection is when it happens, then a run a complete scan and see what module is not talking, something is likely going to show a communication error when the no start occurs. The reason for no codes is because whatever it is self checks later when it does start and passes, so no code.
that's why the dealer and anybody is not going to have a hard time finding it unless it is "actively happening" when diagnosing.
some guesses
crack in fuse box, poor wire connection "somewhere", module getting hot and loosing connection.
I would start inspecting/cleaning at the battery and battery top fuse block, then move over to the fuse box, pull it up and check the connections.
as for the fuel pump, I would check the fuel pressure when it happens versus throwing a fuel pump at it.

 

[sasso]

what you will probably want to do besides a good visual inspection is when it happens, then a run a complete scan and see what module is not talking, something is likely going to show a communication error when the no start occurs. The reason for no codes is because whatever it is self checks later when it does start and passes, so no code.
that's why the dealer and anybody is not going to have a hard time finding it unless it is "actively happening" when diagnosing.
some guesses
crack in fuse box, poor wire connection "somewhere", module getting hot and loosing connection.
I would start inspecting/cleaning at the battery and battery top fuse block, then move over to the fuse box, pull it up and check the connections.
as for the fuel pump, I would check the fuel pressure when it happens versus throwing a fuel pump at it.

Yeah i guess ill try and look for what isnt communicating once it happens again. its at the shop right now so gotta get it to turn off again tomorrow and start working on it again. Will check for fuel pressure, although the scanners live data shows that there is good pressure when i go to crank.

As for the battery, and fusebox, i would assume that it wouldnt start at all, it only has this issue at operating temperatures so im kinda leaning more towards a failing module

 

[Doubeleive]

Yeah i guess ill try and look for what isnt communicating once it happens again. its at the shop right now so gotta get it to turn off again tomorrow and start working on it again. Will check for fuel pressure, although the scanners live data shows that there is good pressure when i go to crank.

As for the battery, and fusebox, i would assume that it wouldnt start at all, it only has this issue at operating temperatures so im kinda leaning more towards a failing module

maybe, the fuse box is a brain of sorts if there was a bad connection leading to say the ecm then it may not start.
It's just something to maybe take a look at, really could be anything.
sometimes intermittent problems can put us at wit's end

 

[Hpb99]

Not sure about a 2023 model but i had the same issue couple yrs ago 99 tahoe, mine was the fuel pump relay, i jumped with a piece of wire & was running only did it on longer runs ( had a bad fuel pump causing it ). Another item to check ,as ive had it happen on a ford & toyota was a bad gas cap ,caused a vapor lock, vehicles would run at night or early morning ,but not during the heat of the day .

 

[sasso]

Alright everyone, so after it being at the garage for a couple of days starting up just fine, they left it on idle for 2+ hours and it wouldn’t stall. I decided to try myself and switched it on, revved it up after it idled for 10 mins, and it refused to stall. I then turned on the AC and it still wouldn’t stall. I then tried to rev it, release the pedal apply the brakes and some steering input and that finally stalled it (still in its place, didn’t drive at all) and it refused to turn on after. Still cranks but doesn’t start. No codes.

 

[blanchard7684]

Alright everyone, so after it being at the garage for a couple of days starting up just fine, they left it on idle for 2+ hours and it wouldn’t stall. I decided to try myself and switched it on, revved it up after it idled for 10 mins, and it refused to stall. I then turned on the AC and it still wouldn’t stall. I then tried to rev it, release the pedal apply the brakes and some steering input and that finally stalled it (still in its place, didn’t drive at all) and it refused to turn on after. Still cranks but doesn’t start. No codes.

Is auto start-stop active when doing this?

 

[sasso]

Is auto start-stop active when doing this?

Yes

 

[blanchard7684]

Yes

Is this more dependent on steering input or brake input?

Edit: if brake input is causing this it could be a leaky brake booster. Any funny whooshing type noises near the brake master cylinder?

If it is steering input my instinct is that something is disrupting the ignition switch . Not sure why it would take 2 hours to show up though…thermal input of some type?

If it is truly the perfect combo of brake and steering then I’m think there is some chafed wiring or something to that effect going on.

 

[sasso]

Is this more dependent on steering input or brake input?

The auto start stop? Not sure. But in park it never switches the vehicle off. Only in D and even if seatbelt is off the vehicle will not switch off

 

[blanchard7684]

The auto start stop? Not sure. But in park it never switches the vehicle off. Only in D and even if seatbelt is off the vehicle will not switch off

See edit. I was thinking it may be good to disable this to see if there is an effect.

 

[sasso]

See edit. I was thinking it may be good to disable this to see if there is an effect.

Tried disabling auto start stop. No change