So I've got this intermittent electrical problem in my ford. 1992 F-150, Straight 6, 4x4. It'll run fine all around town but once I get into about a 1.5 hour drive in the heat, I lose all power. It only happens in the heat. If it's raining or at night time cool air, it'll run just fine.

The truck will sputter and become totally gutless. IT starts off slow, a few sputters here and there and gradually goes ****tier as time goes on. All my gauges read fine and normal.

At first I figured it was the ignition module (ICM)- I heard they can go funny ha-ha when they get too hot. So after letting her sit over lunch time, I replaced the ICM- the one that's mounted above the driver fender well with the heat sink attached to it. Ya gooped it up with the silicone, replaced and rebolted a brand new one in.

1.5 hours later I was stopped again. So on the side of the road, I unplugged the TPS sensor and drove it- no change so I replugged it in. Then I unplugged the other sensor mounted on top of the throttle body- the one that is long and tubular like- no change, replugged. Had to let it sit and cool down again.

I'm also going to change the fuel filter this weekend- I don't think it'll help but it needs a new one anyways. How about the fuel pump? Do they tend to fail when they got hot?? Injectors?
The truck is sometimes hard to start when cold- Have to turn it off because it chugs and chugs, then it starts up just fine? Maybe the pump is weakening?

I've been reading about the PIP stator sensor and PCM Module? Totally confused and at a loss of what could be the problem. I wish these manuals could actually describe what some of these sensors do. And until I go out of town again, I won't know if the problem is gonna be fixed with the parts I decided to replace. The next time I have to leave town will be for the next road/4x4 trip. Can't have it screw up. I don't mind spending a few hundred bucks replacing parts as preventative maintenance either. Any suggestions would be awesome!! Thanks!


Coil (MSD), plugs (autolite) and wires (taylor 8.8) are all new last summer.

 

Sounds to me that it could be the ECT sensor or the fuel pump or maybe both of them.
If it is the ECT sensor you will more than likely get black smoke out the tail pipe as it dies.
The fuel pump could be getting hot and stopping when hot and have normal pressure when cold although you say you have some cold problems also.

A less likely sensor would be the ACT sensor but it would give the black smoke also when hot.

The ECT or the ACT sensor could give the cold problem also.

 

ECT- The coolant temp on my gauge operates as usual -- why would this be a problem??
I guess it helps the computer to regulate the amount of air that enters the engine. From what I've read, this (the ECT), MAP sensor, TP sensor, ACT etc...
Haven't seen black smoke though.

What about EGR and EVP? I've had problems there before. I fabbed up a restrictor plate to prevent exhaust gases from re-entering the throttle body. BUT I took it all out last year and replaced the... ummmm
There's two items you can replace there- I replaced the cheaper one, removed the restrictor plate and the truck worked fine. Even got better gas mileage!

Truck is in the shop today getting 4.56's yeeeehawwww. Then I guess ripping and tearing of sensors and wiring harnesses this weekend.

 

You have two sensors on the engine. One for the gauge and another for the computer. He is suggesting that the one for the computer may be giving false info. This may explain why it will not start very well when cold(no fuel enrichment). The best way to troubleshoot this would be to have a scanner that will read the actual temp data from the computer to see if it jives with the actual engine temp.

 

Then why would my truck run fine for quick jaunts around the city, and for an hour and a half on the highway??
Where can I find this aforementioned sensor on the engine? I'm trying to find it in my Haynes manual again- forget which chapter it's in. My eyes are going buggy!!!

Thanks for all the replies guys, the help on this site is great!!

 

The ETC Sensor has nothing to do with your Temp Gauge.
More information on the ETC Sensor:
http://fordfuelinjection.com/index.php?p=28

Your ETC Sensor is at the bottom center of this diagram.

http://www.autozone.com/images/cds/gif/large/0900823d800a2d25.gif