revyman69

I have an 87 bronco ll that, as a whole runs really good. The engine runs well when the outside temperature is cool, but as soon as the outside temp gets around 25 degrees celceus the engine starts to sputter and will eventially die. After leaving the vehicle to cool it will start and run again untill it heats up again.
Yeaterday i went camping up the mountain and thought because it was at a higher altitude it would run fine, but the same thing happened again. On the trip down the mountain, it ran just fine. The only difference between going up and comming down was the obvious extra work required in climbing the mountain.

I have changed the fuel pump, the computer, and the ignition modual, all with the same result. I have the propper pressure at the rail even when the engine won't run.

It is definately a temp problem but no one seems to be able to diagnose the problem.

Help
Terry

 

LunaticSVT

Examine the entire cooling system for leaks and then check the intake manifold gaskets and head gaskets for leaks.

Have you replaced/checked the T-stat?

revyman69

Hi there! I know this might sound strange but just what exactly is a T-stat?
Terry

'92BigBronco

I agree overheating or a headgasket could be the problem, however your problem smells like a bad TFI module to me. There have been numerous lawsuits and attempts to force a recall for vehicles with distributor mounted thick film ignition modules as they cause the vehicle to sputter and possibly die in traffic in hot weather, causing an accident and potential injury.

The TFI module doesn't like excess heat. As it ages, the module looses its ability to deal with the heat in the engine compartment and will cause you to lose spark intermittently if it gets too hot. Rather than just getting rid of the weak link in the ignition system, Ford opted to move the TFI module from the distributor to a heatsink mounted near the firewall on the drivers side of the engine compartment.

Your '87 is distributor mounted and you'll need a special tool available at any auto parts house for a few bucks to remove it from the distributor. Ford sells the Motorcraft TFI modules for about 80 bucks the last time I checked but you can find a generic replacement for less at most auto parts stores. I would bet that's your problem. If you replace it, be sure to clean the mounting surface well and use new dielectric grease when installing the new module.

Best of luck!

Brian

__________________
1992 Ford Bronco
351W
E4OD- B&M Stage 2 shift kit
Full 3" stainless Bassani Exhaust
32" BFG's/stock suspension

"No replacement for displacement."

"Our lugnuts require more torque than most Honda's produce!"

LunaticSVT

Your TStat is a thermostat.

Brian: I forgot about that TFI issue.