Hey y'all. Trying to get a problem figured out with my F150. She likes to randomly cut off on me when she's warm. I finally found a bad ground cable (yes the one attached to the frame rail where several members were telling me to check), so I replaced that. I'm pulling code 44. Problems in Thermactor Air Control system. Could this be my issue? Where do I need to go from here.

88 F150, I6, C6 auto, 4x4

 

Do you still have the air pump intact? Check that the vacuum hoses to the diverter valves aren't leaking too. if that checks out good it may be the solenoid.

 

Air pump is still on. I did find one vacuum hose disconnected on it and put it back. I've got a few bad small vacuum lines broken I've gotta look at replacing. But just as I was getting done working on the truck, I tried firing it up to move it and it wouldn't start! Just like when it was on the side of the road. I put the scanner on and did a KOEO test and got problem with Throttle Positioning sensor. I'm going to replace that next.

 

Okay. I replaced the TPS. Still wont start. I checked for spark. No spark out of the distributor or the coil. Dang. Where do I look back to, to try and get spark.

 

Ok ... so the coil isn't making any spark.

Could be a bad coil.

It gets more complicated after that. It looks like you've got a distributor mounted TFI module. The ones stamped " Made in France" had a reputation for failure.

It gets hot in that area and the distributor mounted TFI's weren't fitted with an aluminum heat sink like the fender mounted ones were. It's just a shot in the dark but it seems to go hand in hand with the problem you were having with the engine shutting down when it was warm.

There were black ones and grey ones. If you do decide to replace it make sure that the one they give you is the right color.

Also ... check fusible link D with the ignition key in run position to see if you've got power on the far side of it.

It could be a problem with the " pick up coil" on the distributor.
What that does is send a signal to the computer telling it when to fire the ignition coil. If that's not working the computer doesn't know that the engine is turning so it has no reason to make spark.

Long story short .... if it's not a defective ignition coil the next most likely place to look for a problem is somewhere around your distributor.

 

Great info. I did, just the other day, replace my coil. Ill look into replacing said "TFI" module with the correct color. Thanks! But I will check power coming in before I replace it

 

Alright. I got a TFI module and I'm sure others have run into this problem but I don't have the right size socket to fit the small bolts that are recessed in small holes to get the TFI off. A 5mm isnt the right size and a 6mm doesn't even fit in the hole. Do I need a specific made socket for this or something?

 

I ran into that with my fender mounted TFI.

On mine it needed a 7/32" deep socket.

I hope that the new TFI fixes the problem for you.

Seriously considering naming my truck "Christine".



( If you can't find the problem ... blame it on evil spirits.)

 

Lol. Thanks. I used the search function and found it was a 7/32. I had to grind it down a little on the very tip. Working good! I hope this fixes it too!

 

I just remembered ... use some heat sink compound on the back side of the TFI.

The Haynes manual specified Dilectric Silicone Compound. (silicone grease)