Need Wiring -troubleshooting expert please

[Turdle]

1997 mounty 5.0 Belongs to Cybergasm.


Displays p0117 after a few minutes. Idle starts to vary by dropping out and recovering once code is displayed.

Ok break out the wiring diagram and play along please.

Key on engine off voltage check on ECT wire harness (sensor disconnected) is .3v on grey w red stripe wire, 0 on signal wire

sooo
moving over to IAT sensor I see 5v on the gray wire--and the same .3z on the grey with red stripe wire. ( IAT sensor disconnected)

moving over to the TPS I measure the same .3v on the 5v supply wire (grey with red stripe) and a weird 5v on the brown with white stripe wire, also with sensor disconnected. All volatges are harness readings.


For all 5v sensors the grey with red stripe wire is the 5v source. I am reading .3v. However on the ground to the TPS, and, signal wire from IAT I am reading 5v.
I tried disconnecting various 5v sensors with no change, however we have not made it to the dpfe sensor yet.
It would seem the 5v sensor supply line is shorted-however with the 5v present on the signal side---I have to ask


PCM toast?

Is there anything More you would like me to check? Thanks

 

[Tbars4]

..Just trying to help until someone else chimes in..

moving over to the TPS I measure the same .3v on the 5v supply wire (grey with red stripe) and a weird 5v on the brown with white stripe wire, also with sensor disconnected. All volatges are harness readings.

..Sounds like a grounding to me...Could be a wire ground or you could have a toasted PCM due to either a grounded wire or something else..


P0117 ECT ECT indicates 125°C

Voltage drop across ECT exceeds
scale set for temperature 125°C (254°
F) (grounded).

..This should give you some more ideas to try..
http://www.ford-trucks.com/forums/421848-1996-ranger-with-p0117-code.html#post3056241

 

[Dan Whitaker]

1997 mounty 5.0 Belongs to Cybergasm.


Displays p0117 after a few minutes. Idle starts to vary by dropping out and recovering once code is displayed.

Ok break out the wiring diagram and play along please.

Key on engine off voltage check on ECT wire harness (sensor disconnected) is .3v on grey w red stripe wire, 0 on signal wire

sooo
moving over to IAT sensor I see 5v on the gray wire--and the same .3z on the grey with red stripe wire. ( IAT sensor disconnected)

moving over to the TPS I measure the same .3v on the 5v supply wire (grey with red stripe) and a weird 5v on the brown with white stripe wire, also with sensor disconnected. All volatges are harness readings.


For all 5v sensors the grey with red stripe wire is the 5v source. I am reading .3v. However on the ground to the TPS, and, signal wire from IAT I am reading 5v.
I tried disconnecting various 5v sensors with no change, however we have not made it to the dpfe sensor yet.
It would seem the 5v sensor supply line is shorted-however with the 5v present on the signal side---I have to ask


PCM toast?

Is there anything More you would like me to check? Thanks

Having the fun now I was having with Spanky I see.

 

[cybergasm]

..Just trying to help until someone else chimes in..



..Sounds like a grounding to me...Could be a wire ground or you could have a toasted PCM due to either a grounded wire or something else..


P0117 ECT ECT indicates 125°C

Voltage drop across ECT exceeds
scale set for temperature 125°C (254°
F) (grounded).

..This should give you some more ideas to try..
http://www.ford-trucks.com/forums/421848-1996-ranger-with-p0117-code.html#post3056241

Yeah the issue were having here tho is that according to the Ultra Gauge The Temp input to the Computer is reading exactly 0 (zero) Degrees. And that seems to be causing the Bouncing Idle until the motor dies when it is cold but once it is warmed up it seems to do OK.

Having the fun now I was having with Spanky I see.

Yeah but given enough time here i think we will get it figured out here and have her Purring again

We did make a little progress today tho we got the IAT issue sorted now
replaced the IAT with one Turdle had laying on the shelf and found also a better fitting Grommet for the Air intake Tube. so that seems to resolved that issue.

 

[2000StreetRod]

gray/red is common return

1997 mounty 5.0 . . .
For all 5v sensors the grey with red stripe wire is the 5v source. I am reading .3v. However on the ground to the TPS, and, signal wire from IAT I am reading 5v. . . .

The gray/red wire is not the 5V supply for the TPS, DPFE, ECT, CPS and IAT sensors. It is the common return for them (PCM pin 91, signal return). The gray/red wire is also isolated from ground. The 0.3 volts reading is the difference between ground and the isolated common return and is probably normal.

Each sensor has its own source from the PCM. The PCM pin 38 supply connection (LG/RD wire) to the ECT sensor is probably bad (possibly shorted to ground). That would explain your P0117 Engine Coolant Temperature Circuit Low Input. If you can't find a break or short in the wire check the PCM connector for the pin being loose allowing it to push back when the connector is installed.

 

[Dan Whitaker]

We did make a little progress today tho we got the IAT issue sorted now
replaced the IAT with one Turdle had laying on the shelf and found also a better fitting Grommet for the Air intake Tube. so that seems to resolved that issue.

I had the IAT problem with the stock intake tube and I had relaced the IAT. I wonder if I got a bad IAT from O'Reilly's