At the end of my rope. Please help!

[87_PA_Ranger]

Sorry if this is in the wrong place or has been covered. I searched the forum and didn't see my issue.

That said.

I got my 87 2.9l 5sp xlt a few months ago and have been chasing problems ever since.

Currently it's dying and then doesn't want to start. I tried 2 TPS and with both the voltage is normal until half throttle then it goes OL on the multimeter. I don't know if it's a short somewhere in the wiring harness or a completely different issue.

I don't know what to do at this point and now I'm missing work.

Any help is very appreciated
Thanks

 

[Shran]

Welcome to TRS.

Your TPS signal wire should read around +0.75v when the throttle is closed and should increase to about +5v when the throttle is fully open. Any drop offs, spikes, etc indicate a bad TPS, you want to see a nice smooth increase as you slowly open the throttle. Sometimes it's easier to use an analog multimeter if you have one, it's easier to catch bad spots if you're watching a needle as it reacts quicker.

It is possible to get it oriented wrong when you install it - the correct process is to have it turned a bit from its normal position, then insert it, then turn so the screw holes line up. If it's just pushed straight in, the throttle blade won't line up with the sensor correctly and it won't turn the inside of the sensor.

It's also possible to get the wrong sensor, Ford made many variants of these and some of them look the same but are designed to turn in opposite directions. I went through that on my 4 cylinder truck, all of the parts stores listed a sensor that obviously would never work because of that very reason. Eventually I tracked down the right sensor that allegedly only fits a Merkur XR4Ti.... go figure... perfect fit for my truck.

It's also very possible that you got two bad sensors (assuming you bought new ones?) Parts quality is terrible these days.

 

[87_PA_Ranger]

Thanks,

It's at about .77v when closed and gradually goes up until 1.9v then reads OL. I can get it running but then it dies and won't restart.and when it's under load it just loses all power and stalls

 

[Shran]

Thanks,

It's at about .77v when closed and gradually goes up until 1.9v then reads OL. I can get it running but then it dies and won't restart.and when it's under load it just loses all power and stalls

What is your multimeter set on? If it is set to max out at 9.999 volts and the TPS is getting full 12v from the battery, that's probably why you're seeing OL... try the next higher setting so you can have it read up to 99.99.

If you're getting any more than 5v at that sensor, you'll need to find out why. That would be exceptionally weird. The +5v reference wire is shared with a bunch of other sensors and if you're getting full battery voltage there for some reason, the computer would have no idea what to do with that.

Check your multimeter settings & report back to us...really curious what the problem here is.

 

[87_PA_Ranger]

What is your multimeter set on? If it is set to max out at 9.999 volts and the TPS is getting full 12v from the battery, that's probably why you're seeing OL... try the next higher setting so you can have it read up to 99.99.

If you're getting any more than 5v at that sensor, you'll need to find out why. That would be exceptionally weird. The +5v reference wire is shared with a bunch of other sensors and if you're getting full battery voltage there for some reason, the computer would have no idea what to do with that.

Check your multimeter settings & report back to us...really curious what the problem here is.

That was the problem with the voltage. I was so pissed off about the truck I didn't pay attention to the setting. Now I have to go back to figuring out why it's not running. Thanks for the advice.