1989, 5.0, 4 sp, 4x4, A/C, EFI, F150 Custom. i will say before i ask, i have searched this forum, online and still cannot find an answer. maybe my key words were not accurate? problem is my truck died at a stop sign the other day while in neutral with A/C on AFTER i went to O'Reilly trying to find out which coolant/temp (same?) sensor i needed. maybe the guy wiggled a wire? but it started in the parking lot and drove 3 miles until it died. when i turned the key, it sounded like it was not getting enough amps {cables are fine) i popped the hood, and everything on the batt was tight, i wiggled the runners and turned the key and it started right up!. that was 2 weeks ago, not a problem since. but my temp gauge has not been working for about 3 months while the truck is on, it does show the temp about 15 min after i turn it off and it is normal. i have read there is a 1 wire connector/switch that needs to be replaced, well i see 2 sensors and they both have 2 wires. some posts do not say which engine they are referring to so that does not help and that is why i am here. i see a sensor behind the distributor with a yellow and red stripe and black. and another green with a black stripe and black to the left of the dist. i plan on replacing them both, but for now i just want to replace the right one. sorry for the novel but i thought some background might help. other than it dying, i have had it a little over 2 years and not a problem at all. still runs perfect without the gauge working, i was told that it might act up in colder temps, but that will not be here until oct/nov, i live in So Tx and we are not hurting for hot weather. thank you fellow Ford guys and gals. oh!! i also have a Haynes, and it was of no help, if so i would not be here. maybe chilton in the future?

 

Hi,
I'm not a Mechanic but have owned a 89 F150 4.9L for 25 years!

I just went thru (going though?) my truck shutting down.

I would suggest running the codes first off!

Right now you have no info what so ever.

The sensor might not have anything to do with the problem? (temp SENDER or SENSOR???)

Could be electronic, coil, pip sensor,TFI, ect.,ect.

Could be fuel pressure, fuel pump, ect.

Just sayin run the codes and see if you get a lead???

 

I definitely agree that you should check for codes. I recently bought an Innova Ford OBDI scanner off of Amazon (https://smile.amazon.com/gp/product/...?ie=UTF8&psc=1). Best $20 I've ever spent on my truck.

I'm not sure that not reading the coolant temp sensor (engine coolant temperature sensor, or "ECT") will cause a no-start, but either way, checking for codes is a great place to start. Just be sure to do KOEO codes and fix any problems there before trying KOER, otherwise the KOER codes are meaningless.

Also, the two sensors do different things. Unfortunately, I don't know which is which for you since I have the 4.9 and am only familiar with the locations on that. One is the "temperature sensor" (located on the thermostat housing on the 4.9), which sends the coolant temp info to the computer. The other is the "temperature sender" (mine is on the passenger side of the block toward the firewall end), which sends temp info to the gauge in the dash. I also recently installed an Autometer temperature gauge (comes with a new sender) and couldn't be happier to have a source of engine temp that I am confident in (and has actual numbers on it...).

 

The temperature sender for the gage is closer to the distributor than the other one you found. Single Red wire with White Stripe.

 

I don't think it would cause a no-start scenario either.

An open circuit to the ECT would produce a code, and negatively affect the Idle.

 

X2, I agree with me

 

The temp sender runs the gauge and has nothing to do with the computer or how the motor runs. It is on the driver's side front of the intake between the first and 2nd bolts.

The sensor, which does send a signal to the ecm is on the standpipe above the thermostat.

 

thank you for clearing that up, when i have the time i will be replacing it. and thanks to everyone else for your time and efforts.