09 prostar with ISX randomly shutting down

[in2trux]

(02-07-2017 )09pornstar Wrote:  

(02-07-2017 )gearhead Wrote:  When the engine won't start i would go and check main ecm power when it won't start. It may have thermal fuse that when.

I already checked that and its a regular red fuse(dont know for sure the amps) and it looks new, not melted or burnt. I mean could the fuel shut off valve get hot somehow? That thing is electronic controlled right? Cause after the engine stops it wont fire up for 5-7 mins, its like something got hot and it cools down..

Like Gearhead said, look for a thermal breaker near the ecm. Not the spade type fuse. They can be silver or black metal cover and can also be in the fuse block.
Those are the exact symptoms. It takes about 5 minutes for them to cool down and reset. It may be weak and a simple replacement. They can overheat from high ohms or voltage
Like everything , they do fatigue with age.
You might check voltage to fuel cut off solenoid, center of IFSM, between the actuators.
A weak solenoid could act the same.

[Waterloo]

Check for that thermal breaker, and for good measure replace that spade style fuse, and check the contacts in the holder. These fuses will go buggy and still look ok. It has happened in my dash on more than a few occasions. The scan that the dealer can do only takes a few minutes, literally. What a bunch of bone heads. I would pull up at lunch time and flip one of the mechanics $20 bucks to bring the laptop out to the truck, plug it in and look for any codes.

[09pornstar]

(02-08-2017 )Waterloo Wrote:  Check for that thermal breaker, and for good measure replace that spade style fuse, and check the contacts in the holder. These fuses will go buggy and still look ok. It has happened in my dash on more than a few occasions. The scan that the dealer can do only takes a few minutes, literally. What a bunch of bone heads. I would pull up at lunch time and flip one of the mechanics $20 bucks to bring the laptop out to the truck, plug it in and look for any codes.

Thanks a lot! I was thinking it should be one of the two..is it ok to temporarely bypas a fuse like that?
I'll try to eliminate that and if its still shutting off then it must be the selenoid..

[09pornstar]

One question. Is the fuel actuator selenoid supposed to get burning hot? That is the only thing that im thinking it could shut off the engine

[in2trux]

(02-08-2017 )09pornstar Wrote:  One question. Is the fuel actuator selenoid supposed to get burning hot? That is the only thing that im thinking it could shut off the engine

If it's getting too hot to touch that may be the source of your problem, putting high load on thermal breaker. Fuel cut off is energized to open, normally closed at key off.
You really need to look at a schematic for your truck and locate all the potential problem spots.
These are the little things that spending an afternoon on a warm day are well spent come February.

[Rawze]

(02-08-2017 )09pornstar Wrote:  One question. Is the fuel actuator selenoid supposed to get burning hot? That is the only thing that im thinking it could shut off the engine

they are normally hotter than the rest of the solenoids. This one was 103 degrees with he rest of the engine still cold and warming up.



How much hotter? -- not sure, but it is normal for them to be hoter than the rest to some extent.

===

My shutoff solenoid put my truck on the side of the road with no warning when it went bad. I had to remove its guts and tape the wire off so it would get fuel. That got me off the side of the road.

I ran it like that for a few days, and since it ran just fine like that, I decided not to replace it, but to suppress the code for it being disconnected in the ECM instead. - That was more than 4 months ago.

[09pornstar]

Thanks all for your replies! Mine its so hot that after i shut off engine i can hear that metal cooling down so i dont think thats good. I asked my guys at home to tell me if theirs is hot and they all said its no hotter than the other 4. I got the new selenoid and im about replace it now, if the shut off persists then we got something else going on.

[09pornstar]

(02-08-2017 )Rawze Wrote:  

(02-08-2017 )09pornstar Wrote:  One question. Is the fuel actuator selenoid supposed to get burning hot? That is the only thing that im thinking it could shut off the engine

they are normally hotter than the rest of the solenoids. This one was 103 degrees with he rest of the engine still cold and warming up.



How much hotter? -- not sure, but it is normal for them to be hoter than the rest to some extent.

===

My shutoff solenoid put my truck on the side of the road with no warning when it went bad. I had to remove its guts and tape the wire off so it would get fuel. That got me off the side of the road.

I ran it like that for a few days, and since it ran just fine like that, I decided not to replace it, but to suppress the code for it being disconnected in the ECM instead. - That was more than 4 months ago.

Thanks for your advice Rawze! Mine is so hot that ill get a burn if i touch it too long.. the rest are luke warm. What do you mean you took its guts out and taped the wire? Is the fuel valve than always open? I never tought of that haha

[09pornstar]

So just an update...i changed that selenoid and now im on the side of I80 between Wendover and SLC.. its still doing it.. same faults on the screen low coolant, abs and electrical fault. At this point i'm at a loss for words