Weird TPS voltage...4.9xvolts

[Lethal Injection]

As of late my tuned 92 fox has been intermittently idleing high and not starting. When it doesnt start there is a strong odor of raw fuel, occasionally i can get to fire with the throttle fully open.

I started checking through things and thought i had it nailed when my tps was at 4.9volts. I had a couple of others that i was positive worked, so i put one on and still the same 4.9x volts regardless of how i turned it.

Is this something that can/has be adjusted through the tune? If not where would you start? the comp?

[TENGRAM]

At the sensor, check continuity from SigRTN (black) wire to ground with battery disco'd. Should be less than 5 ohms, else you have an open SigRTN and you need to trace the break. There is commonly a burnt trace on the back side of the ECM circuit board.

[greenbullitt]

As of late my tuned 92 fox has been intermittently idleing high and not starting. When it doesnt start there is a strong odor of raw fuel, occasionally i can get to fire with the throttle fully open.

I started checking through things and thought i had it nailed when my tps was at 4.9volts. I had a couple of others that i was positive worked, so i put one on and still the same 4.9x volts regardless of how i turned it.

Is this something that can/has be adjusted through the tune? If not where would you start? the comp?

are you sure youre checking the right wires?

[kingjason]

are you sure youre checking the right wires?

Yeah maybe you are checking the reference wire. It should be around 5v.

[turbostang]

are you sure youre checking the right wires?

Agreed. I think he's checking the 5V input and not the output.

[Diabolic]

X4

[Lethal Injection]

Im checking the green wire...

Ive got another 92 here and it reads correct @.98v

[Lethal Injection]

At the sensor, check continuity from SigRTN (black) wire to ground with battery disco'd. Should be less than 5 ohms, else you have an open SigRTN and you need to trace the break. There is commonly a burnt trace on the back side of the ECM circuit board.

2.14ohms from the black wire at the sensor to a ground.

[greenbullitt]

did you try a different sensor for reference?

[Lethal Injection]

did you try a different sensor for reference?

Yes, same voltage. Ohms close as well @2.34

[shumpertdavid]

Unplug the sensor and check the voltage again, if the green still has 4.9 volts, it may be shorted to the 5 volt reference(orange wire) somewhere in the harness.

[shumpertdavid]

FYI, at WOT or if the tps signal wire sees at or near VREF (5 volts), it will go into clear flood. This means the injectors will be turned off while cranking.

[greenbullitt]

Unplug the sensor and check the voltage again, if the green still has 4.9 volts, it may be shorted to the 5 volt reference(orange wire) somewhere in the harness.

time for overlays!

[shumpertdavid]

time for overlays!

if it's shorted this would be a lot easier than tearing the harness apart to find the problem.

[TENGRAM]

2.14ohms from the black wire at the sensor to a ground.

As these guys said, that really only leaves the possibility that the VREF is shorted to TP wire. Could be in the harness or the ECM. Trace and repair or run a new TP wire from the ECM (pin 47) to the sensor. If that doesn't cure it then your ECM is the problem.

http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif