Heat Soak Problems

[farmersammm]

The 1 ton refuses to run after it's been run hard. It will stall once you come to a stop, and refuse to start until the motor cools down. Prior to stalling, it runs with reduced power.

At first, I assumed it was vapor lock. Being as it would restart after you pop the hood, and let it sit for half an hour.

This happened again on Sunday while hauling hay. Stalled in front of the driveway.

Restarted fine after cooldown, but it did something that's leading me to think it's not a fuel problem......................

Ran like crap in the driveway while going up a slight grade........engine under minimal load. BUT.....the damn thing ran perfect going down a slight grade

This motor uses a coil, and a module in/on the distributor, and some sorta module on the firewall. I'm wondering if there's a heat problem in one of these electrical components.

For the past year, the thing has had dropping power. Used to run 70mph with a 10K load, now it's doin' good to maintain 55mph in most situations.

Gotta head to town today to pick up some stuff, might pick up an inductive thingy to check spark at the plug wires in order to see if the thing's getting spark when this happens. No other way to test it I'm thinkin'. No good way to replicate heat soak

[M J D]

Lisle makes a good inline spark tester that you can run the motor with while plugged in. If it dies again, check for spark and if none present, ice down the module and retest.

[mrmikey]

Check the grounding of the module on the firewall, if I remember right, that was a common problem. If it checks out good, get a heat gun on a cold engine and heat up the different components until the problem shows up or the opposite way as MJD said above with ice.............Mike

[rexcormack]

If it is a Duraspark system(cast aluminum ignition module on the drivers side fenderwell) it is probably the pickup module inside the distributor.
I've had several do the exact same thing you describe and it was the pickup module.

If it is a TFI system(small ignition module bolted to the side of the distributor) it could be either the pickup module or the TFI module!
You will need a special wrench to remove the TFI module screws! https://www.amazon.com/Lisle-64650-I.../dp/B0002STS30

[OPUS FERRO]

farmersammm

Do you have any electrical accessories
that bypassed the ignition switch?


Opus

[MinnesotaDave]

If it is a Duraspark system(cast aluminum ignition module on the drivers side fenderwell) it is probably the pickup module inside the distributor.
I've had several do the exact same thing you describe and it was the pickup module.

If it is a TFI system(small ignition module bolted to the side of the distributor) it could be either the pickup module or the TFI module!
You will need a special wrench to remove the TFI module screws! https://www.amazon.com/Lisle-64650-I.../dp/B0002STS30

That makes sense, my memory says the Duraspark box will die once, restart to get you home, but not many more after that (if any).
The module can do strange things for a while before finally dying.

[farmersammm]

I'll try the heat gun. All I have is a hair dryer........if it doesn't work I'll go get a heat gun. And I'll carry some water in the truck to see if it works when it's hot. Douse it on the module.

Ran it today,, and no problems stall wise......no real power, but ran ok. It was below 90* today, so that tells ya somethin' I guess.

Thanks!!!!!!!!!!!!!!!!!!! I'll try the things you guys said.

BTW.......it's a Ford system, so that ought to make a difference. I know where the stuff is, so I'll be able to mess with it.

[gnewby]

Sam you might try calling Oreillys and see if they can test the Modules for you. You would probably need to pull them off of the truck and have another vehicle to run them in to be tested. The local Oreillys near me does a pretty good job of testing these and if you find the right person in the store a lot of times they can do stuff to replicate the problem to see if it works then doesn't.

[bigb]

One thing I remember from the older systems is occasionally a hairline crack can develop on the coil and cause issues when it heat's up. Just one more thing to think about.

[farmersammm]

All components were tested with a heat gun, trying to make the truck stall. Nothing showed any signs of problems. Starter/battery relay, fuel pump relay, ignition module, distributor housing (pickup sensor), and ignition coil. I'm convinced that the problem is NOT electrical at this point.

Next up is where I really started.................the fuel system.



Nothing is definitive here either. The fuel regulator tests good, but it might be the fuel pump getting hot after running for a while. I would like to see the pump run up to 45psi, but it's sort of within specs at this point.

I can let it run for an hour, engine off..........but I figure it's easier, and more definite, if I current ramp the pump. Ordered a low amp probe for my scope, and figure I'll find out more when it gets here (shrug)

BTW The rear tank fuel pump failed on the F-150 Friday. Luckily it puked about 3/4 mi. from the house, so the walk wasn't too bad. The front tank ran out of gas, and when I switched to the back tank.................nothing.........no hum from the fuel pump

Sadly........neither problem is a parts changer deal. Motorcraft pumps for these trucks run between 3 and 400 bucks You better be right before you go out and spend near half a grand.

[12V71]

Just for fun, check the fuel pump plug on the top of the tank. Not sure about Fords, but the 90's Dodges would heat up the terminals and die, after cooling off the pump would run a while again. Usually by that time the pump needed replacement because the terminals were nearly burned off. The new pumps came with a replacement harness to splice in.

[farmersammm]

Just for fun, check the fuel pump plug on the top of the tank. Not sure about Fords, but the 90's Dodges would heat up the terminals and die, after cooling off the pump would run a while again. Usually by that time the pump needed replacement because the terminals were nearly burned off. The new pumps came with a replacement harness to splice in.

I will definitely check that out. About 5 days ago we went to town to take a big load of crap to the local transfer station in the F-150, and I ran over a branch on the road (we had a bad ice storm the week prior), and it bounced along underneath the truck............so an electrical check is definitely in order. Won't hurt to do the same on the 1 ton.

I think I can get my hand up there to check either truck. Sadly, it's a bed-off for pump replacement on both of the damn trucks. I don't care to have to fight with rusted fasteners in order to drop the tanks. Easier to just lift the bed off (hopefully with no incidents)

[William McCormick]

I will definitely check that out. About 5 days ago we went to town to take a big load of crap to the local transfer station in the F-150, and I ran over a branch on the road (we had a bad ice storm the week prior), and it bounced along underneath the truck............so an electrical check is definitely in order. Won't hurt to do the same on the 1 ton.

I think I can get my hand up there to check either truck. Sadly, it's a bed-off for pump replacement on both of the damn trucks. I don't care to have to fight with rusted fasteners in order to drop the tanks. Easier to just lift the bed off (hopefully with no incidents)

I used to drop the tanks on the E-150s all the time, they come down pretty easily. I would not attempt the bed though, haha. You have the fuel fill and harnesses to the lights. Sometimes the fuel fill never goes back right without buying a new rubber fuel fill piece and clamps.

Sincerely,

William McCormick

[cwby]

Cut out a hole in the bed over the fuel pump, then plate it when your done. Just a darned old work truck!

[farmersammm]

Not sure when the amp probe will arrive.

https://www.amazon.com/Hantek%C2%AE-.../dp/B06W2KFZLW (I bought off of Fleabay, Bezos has enough money, doesn't need mine)

It's identical to the one that OTC sells for their scopes, probably made in the same factory.



Probably has $3 worth of components in it

[12V71]

Cut out a hole in the bed over the fuel pump, then plate it when your done. Just a darned old work truck!

When I build work/flatbeds for people, I try to incorporate a fuel pump door into the bed. They might have to unbolt a toolbox to get there, but the door is there.

[BaTu]

I had a marine engine drive me Nuts doing just what you describe once. Turned out to be a bad rotor. This was the type of rotor that pushed-down onto the distributors shaft and, when the shaft got hot it swelled enough to open a crack and allow the coil connection, at the center of the rotor, to pass the high voltage to ground...

[farmersammm]

I had a marine engine drive me Nuts doing just what you describe once. Turned out to be a bad rotor. This was the type of rotor that pushed-down onto the distributors shaft and, when the shaft got hot it swelled enough to open a crack and allow the coil connection, at the center of the rotor, to pass the high voltage to ground...

This is just plain stupid. That truck has spent more time sitting in the yard than it's spent on the road for the past year. Sat all Winter while I did the EGR tube, and now this. Geez. I know I'm slow at this, but sometimes it really gets under my skin.

[farmersammm]

Supposedly, this high fallutin' probe will allow me to "see" what's goin' on in the pump. Determine how fast it's running, whether the brushes and commutators are good, see if there's a blockage in the fuel line to the injectors, if amp draw is within specs, and a couple of other things.

It's a brave new world, and I'm not sure I'm really caught up with it yet.

[William McCormick]

I'll try the heat gun. All I have is a hair dryer........if it doesn't work I'll go get a heat gun. And I'll carry some water in the truck to see if it works when it's hot. Douse it on the module.

Ran it today,, and no problems stall wise......no real power, but ran ok. It was below 90* today, so that tells ya somethin' I guess.

Thanks!!!!!!!!!!!!!!!!!!! I'll try the things you guys said.

BTW.......it's a Ford system, so that ought to make a difference. I know where the stuff is, so I'll be able to mess with it.

What kind of styling moose do you use with your hairdryer, hahahahahaha. Couldn't help myself Sam sorry.

Sincerely,

William McCormick

[William McCormick]

Not sure when the amp probe will arrive.

https://www.amazon.com/Hantek%C2%AE-.../dp/B06W2KFZLW (I bought off of Fleabay, Bezos has enough money, doesn't need mine)

It's identical to the one that OTC sells for their scopes, probably made in the same factory.



Probably has $3 worth of components in it

I don't think that one comes with a NIST certificate, haha. But it looks pretty cool. I wonder how accurate they are?



Sincerely,

William McCormick

[William McCormick]

The 1 ton refuses to run after it's been run hard. It will stall once you come to a stop, and refuse to start until the motor cools down. Prior to stalling, it runs with reduced power.

At first, I assumed it was vapor lock. Being as it would restart after you pop the hood, and let it sit for half an hour.

This happened again on Sunday while hauling hay. Stalled in front of the driveway.

Restarted fine after cooldown, but it did something that's leading me to think it's not a fuel problem......................

Ran like crap in the driveway while going up a slight grade........engine under minimal load. BUT.....the damn thing ran perfect going down a slight grade

This motor uses a coil, and a module in/on the distributor, and some sorta module on the firewall. I'm wondering if there's a heat problem in one of these electrical components.

For the past year, the thing has had dropping power. Used to run 70mph with a 10K load, now it's doin' good to maintain 55mph in most situations.

Gotta head to town today to pick up some stuff, might pick up an inductive thingy to check spark at the plug wires in order to see if the thing's getting spark when this happens. No other way to test it I'm thinkin'. No good way to replicate heat soak

I was just reading your post again there is a device that when it gets hot it keeps the vehicle from starting. I forgot what it is offhand, but I got stuck once because of it, on a GMC van. I will see if I can find out what it was.

Sincerely,

William McCormick

[William McCormick]

Supposedly, this high fallutin' probe will allow me to "see" what's goin' on in the pump. Determine how fast it's running, whether the brushes and commutators are good, see if there's a blockage in the fuel line to the injectors, if amp draw is within specs, and a couple of other things.

It's a brave new world, and I'm not sure I'm really caught up with it yet.

Is the pump frequency driven?

Sincerely,

William McCormick

[farmersammm]

Bill:

I believe the probe has various accuracy levels at different settings. I think the error is around 2% IIRC. Have to look at the specs to verify.

The fuel pump doesn't have a "driver". It's an old fuel system with a return to tank line. The pump just runs flat out all the time.........the regulator just allows fuel to return to the tank according to fuel demand. I've read that the more modern systems do have a driver module that varies pump speed according to fuel demand (no return line back to tank), so this one ought (yeah right!) to be easier to diagnose.

[William McCormick]

https://www.autosafety.org/ford-tfi-...ss-settlement/

This I believe was the device that went on the GMC Savana Van.

Sincerely,

William McCormick