1988 Bronco II,A4LD,2.9 F.I. My son`s BII only gets about 10 mpg...seems the converter dosen`t lock (unlock?) like it should while driving ( get to 55 tap brakes watch for tach to drop and it doen`t).Was on here reading old post and found one that says the converter won`t lockup if engine temp is below 60* so here the question...the temp gauge in the dash has not worked since he got the truck so I cecked and the gauge works so sensors bad...is this the same sensor that works the converter?Thanks all for your time

 

Normally two temp sensors. One is a single lead sensor to the right of the thermostat housing (as looking at the front of the engine) that controls the temp gauge. The computer input temp sensor I believe is just behind and to the left of the thermostat housing and has a couple of wires running to it. The gauge temp sensor is pretty cheap at most auto parts houses and I'd highly recommend either fixing it (even though it's not 100% accurate when working? It's better then nothing) or removing it and using an aftermarket gauge. With a 2.9v6? Last thing you need is to have that puppy overheat and not know about it.

S-

 

so the converter lockup is controled by the other one...I`m putting the temp sensor and heater core in soon but was hoping I could solve two problems with one fix... any how thanks for your reply

 

I don't think the A4LD waits for engine temp to rise before locking the TCC, I haven't seen it in any of ours anyway. But if the motor doesn't get up to running temp it will effect fuel mileage.

Do whats needed to insure it does and see if it corrects the TC lock up issue at the same time, if not post back and I'll post a couple of quick and easy tests if you want so you can verify if its a tranny fault, or a computer fault issue.

 

ok replaced the sensor and no help danr1 what test were you talking about?thanks

 

Find the 3 wire connector down on the transmission, driver’s side above and near front comer of pan, sticking straight up. It will have a red wire “key on” constant power 12v+, a P/Y (TCC) and the O/Y (over drive) wires. Make sure e this connection is in good shape and making good contact, when you have the connector unplugged verify key on power to it on the red wire.
If that is found working, power to it and all looks good you can connect a 12v light to the converter clutch lock up wire. To do so connect the light to a 12v+ source under the dash, the other light wire to the converter lock up wire found out under the hood (also found at pin #53, computer main connector behind passenger side kick panel). The wire you want is the Pink/Yellow wire shown in the diagram bellow. Position the light so you can see it while driving, when the computer gives the command to lock the TCC the light will also glow.
That will eliminate the computer as the problem and then you can move on to the tranny and or wiring itself.

You can tap into the P/Y wire out under the hood and extend it inside in reach of the driver’s seat with any handy length of wire, locate a good "ground" that is handy in reach of the drivers seat (sig lighter outer ring?). Then take it for a ride, get up to speed, say 40ish or so running in drive and ground that wire. If the tranny is working right you will feel the TCC lock up and the rpm’s will drop some. If it doesn’t you have a connection issue, a valve body issue or a bad solenoid, solenoids rarely go bad.
You can chose what order you want to do the tests based on what is quicker and easier for you using what you have on hand.



Keep in mind this manual is known to be wrong on wire color from time to time, so your wires may be different. If they are different you can easily find out what color was used on yours by verifying it at the main computer connector. For the TCC lock up wire color, just look at the wire connected to pin number 53 on that connecter.

Scroll down this page some to see the pin layout of the computer’s main connector.

Ford Fuel Injection EEC Computers

If you need me to clarify any of that just let me know, tried to use a few words a possible! LOL

 

thanks danr1 for the tests and links.