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Have a friend making his way back from Missouri to CA . Truck ran fine to MO, now on return trip the truck is dying when he exits hwy and enters city traffic. Let's it sit 30min and it fires back up but will die again while in traffic.
He also had a blow out and is spending the night (pulling an R-Pod trailer) until a Firestone tire center opens tomorrow AM. He's currently on OK City.
Truck has 80K miles.
NOTE: It was previously my truck and was/is well cared for. Many new parts....those related to ignition/fuel..... fuel filter, plug wires, plugs, 4 years ago. Truck has always run great. Never any issues until today.
1992.... Did that year still have the TFI mounted on the dizzy? Could be it's running hotter in town and the TFI is dying..... then there's a lot more cool air getting to it on the highway.
First thing to do is check if it's spark or fuel cutting out when it dies.
To check spark, pull a plug wire off, stick a spare spark plug in the end of it, and hold it against the block or intake manifold to ground it while someone cranks the engine. Watch for visible spark. I recommend wearing welding gloves while doing this.
To check fuel, cycle the ignition a few times to prime the pump. Press the schrader valve on the fuel rail, there should be good pressure and a squirt of fuel coming out.
This sounds like an air flow or vacuum leak related problem. Is it idling OK?
Things to check:
1) Diagnostic codes - even if the CEL isn’t lit codes could be stored.
2) IAC valve - unplug at idle, engine should die or severely stumble before recovering - it could be temperature related so if it passes the test cold, also try it hot
No idling issues. It's an OBD I so very few codes and he doesn't have a code reader.
So, they installed new tires (blow out) and engine cooled while they were being installed. Fired up went to gas station and filler her up. Fired up an got on hwy. After about an hour on hwy, they hit stop and go traffic. Engine started to stall so they immediately pulled over. Now they are stuck on hwy, waiting for engine to cool so they can start and get off hwy. They are still in OK.
As noted previously to narrow down the root cause check for spark when the engine will not fire up.
A 1992 model year F-series gas engine truck has the TFI module located on the driver side inner fender near the hood hinge. The gray modules are known to fail under heat load, but being remote mounted it is rare. The symptoms point to a bad PIP (stator) inside the distributor.
He’ll have to check for spark and follow the tests in the video posted by torq’ta to determine if it’s the TFI.
The reason I don’t think it’s the TFI is because the TFI would most likely to kill the engine regardless of RPM or city vs. highway driving.
An air flow/vacuum leak issue tends not to be noticeable (by the PCM) at higher RPM.
Edit: One other possibility is the torque converter clutch is failing to release after it locks up. That will also kill the engine when slowing down from highway speeds.
My money is on the TFI. Its a known issue on early 90's ford. In stop and go traffic, theres little airflow over the engine and parts become heat-soaked, including the dizzy. At freeway speeds, theres enough air flow to keep things cool and working.
The TFI module is held on by 2 5.5mm bolts, I believe. Youll need a thin wall socket to get the bolts out. Good luck.
A 1992 model year F-series gas engine truck has the TFI module (aka ICM) located on the driver side inner fender near the hood hinge.
As noted in my previous reply the gray Ignition Control Modules when mounted remotely are reliable. Given the age of these trucks it's worthwhile to remove the module to verify the heat sink compound has not dried up.
It was the ICM......Not sure where it is located on the truck. Mechanic also checked dist cap and rotor and said they were worn. I replaced cap and rotor with Motorcraft back in 2014. is 7 years about what they last?
BTW....after it died the last time, on hwy, it sat for several hours until a tow truck arrived. He tried to start after it cooled and t would not start again, as it did earlier in the day.
Thanks for all the help! Much appreciated!! Another old truck issue resolved!!
Glad to see they got it going. The remote mount ICMs are less susceptible to the the heat induced failures. I wonder if the heat sink compound dried up which prevents the flow of heat from the ICM to the heat sink.
05-22-2021, 07:48 PM
