88 2.9 coolant temp sender

[Gashawg2]

I just inherited an 88 bronco 2 with the 2.9, auto and 4x4. The under hood wiring seems to be a mEAs so I’m going through all of it. I’ve looked at the wiring schematics and I cannot find the color wire that should go to what I believe is the coolant temp sender for the gauge. Currently there’s a 2 wire sender with pigtail in the hole (right side of engine) that isn’t hooked up, there’s another two wire sensor on the left side that is the sensor ( lt green/yellow and black wires).

I need to know what color wire to look for that should go to the temp gauge sender along with a part number for the correct sender. Thanks!

 

[Uncle Gump]

My 86 2.9L shows a R/WT single wire to the sender. It's a single wire sender. Your 88 should also be a single wire sender... but the wire color could be different. I don't have an 88 EVTM to verify.

 

[Gashawg2]

My 86 2.9L shows a R/WT single wire to the sender. It's a single wire sender. Your 88 should also be a single wire sender... but the wire color could be different. I don't have an 88 EVTM to verify.

Thanks, I’ll look!

 

[rstanovich]

Napa #TS6628 1 wire Water temp sensor just installed 4-5 days ago so part number is good. now my temp gauge is working.

 

[Gashawg2]

Napa #TS6628 1 wire Water temp sensor just installed 4-5 days ago so part number is good. now my temp gauge is working.

Thanks, I’ll order one. Im still searching for the wire lead though. I don’t have a loose red/white wire

 

[XTC90BII]

Where is that Water Temp Sensor located on a 1990 2.9L?
Dennis

 

[JerryC]

My 86 2.9L shows a R/WT single wire to the sender. It's a single wire sender. Your 88 should also be a single wire sender... but the wire color could be different. I don't have an 88 EVTM to verify.

A little late to the party... mine is a dark red with white stripe. I had to clean off 34 years of grime to find that out, other wise it appeared to be solid black.

 

[XTC90BII]

Jerry C

Where is the sender located on the 2.9L engine itself?

Dennis

 

[JerryC]

Jerry C

Where is the sender located on the 2.9L engine itself?

Dennis

I just realized that I assumed we were talking about the temp gauge sender. If so... It's to the right and behind the thermostat housing.
The one on the left is the coolant temp sensor that the ECM uses for as part of the engine management, A/F ratio, idle speed, TPS position, etc...

 

[XTC90BII]

JerryC

Thanks ordered one from RockAuto yesterday. The pictures shows the threads wrapped in something which I am assuming is a thread sealant against water leakage?

Dennis

 

[JerryC]

I went and took a close look. That's just just crud and some random debris making it look that way in the picture.

I thought it would be odd if there was tape or other sealant as the threads provide a ground for the circuit. But with the stuff the previous owners had done to the BII I wouldn't have been surprised either.

 

[Uncle Gump]

I still use pipe thread tape on those connections. It still gets to ground. As with most things... more isn't always better.

Many of the new sender/sensors will have a bit of sealant on them right outta the box.

 

[XTC90BII]

I was talking about the new sender coming from Rockauto. That is the one the threads have some type of sealeant on them I believe?

Dennis

 

[JerryC]

I did some googling, most say teflon tape is not good but liquid sealants are if they are conductive.

I looked at sending units online and some have no sealant applied to them and some do. The Motorcraft part I looked had the sealant between bare threads top and bottom. Could that be to ensure a good ground? Or simply because because there engagement of those threads when installed?

IMHO I don't think it will take much of connection to work as the current is so low, but it would have to be good connection with no/almost no measurable resistance so as to not affect the reading of the gauge.