Have only read a few threads about this but my 93 idi shifting is inconsistent before and after the rebuild . Most of the time it shifts fine and then once in awhile it's goes from 3td right to fourth , sometimes a hard shift sometimes a soft shift . I read that it's a characteristic bc of the poor programming . Has anyone ( I'm aware there's no programmer or chip available ) had any luck getting these things dialed in better ?
E40d characteristics ??
- Thread starter Gachris
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BeastMaster
Full Access Member
Check your TPS, aka FIPL.
They wear. And don't put out a linear signal, or just as bad, put out a noisy signal.
Also Check your tach sensor for magnetic debris at the sensor end, abrasion of the wiring, or poor connection.
I have had similar issues with mine. One of the bugs was an intermittent in the PSOM that took a battery powered oscilloscope to ferret out.
They wear. And don't put out a linear signal, or just as bad, put out a noisy signal.
Also Check your tach sensor for magnetic debris at the sensor end, abrasion of the wiring, or poor connection.
I have had similar issues with mine. One of the bugs was an intermittent in the PSOM that took a battery powered oscilloscope to ferret out.
BeastMaster
Full Access Member
I'd hate to send you on a wild goose chase with a PSOM. Those are both time consuming and expensive. And often not productive.
The first indication of PSOM problems is an unstable speedometer reading.
The gremlin I had was an intermittent in the circuit that drove the E4OD control module.
Do you have access to a battery powered oscilloscope?
If you can intercept the PSOM signal to the TCM under the hood, it will be a lot easier. Look for a squarish shape pulse, about 8volt amplitude, 0 to 4 KHz or so, as speed varies. If it's a clean periodic pulse, does not change during malfunction, then it's some other goose. Mine was noisy and frequently dropped out like a bad phone call. After I replaced the speedometer module, it's now a much cleaner pulse train that changes frequency with vehicle speed, and it's amplitude is constant and looks like that in the link below.
Read this:
https://atracom.blob.core.windows.net/gears/2007/2007-01/2007_01_04.pdf
https://www.harleyhummerclub.org/PSOM/index.html
I had no luck finding anyone local that knew much more than reading a scanner.
I know it's possible to troubleshoot with an Android phone loaded with:
https://f-droid.org/en/packages/org.billthefarmer.scope
What it will take is making a custom "scope probe" to attenuate the PSOM levels to that approximating the microphone, and jacking it in via the phone's headset/microphone inlet.
It's hard to find good electronics guys... Nobody wants to mess with chasing electronic gremlins. But if you keep probing at it, you will find it.
Incidentally, check your solenoid wiring going into the transmission, at the transmission. These wires are exposed to some nasty environment and transmission heat, and can deteriorate in both insulation integrity and continuity. I have seen photos of stuff that made me wonder how it worked at all.
The first indication of PSOM problems is an unstable speedometer reading.
The gremlin I had was an intermittent in the circuit that drove the E4OD control module.
Do you have access to a battery powered oscilloscope?
If you can intercept the PSOM signal to the TCM under the hood, it will be a lot easier. Look for a squarish shape pulse, about 8volt amplitude, 0 to 4 KHz or so, as speed varies. If it's a clean periodic pulse, does not change during malfunction, then it's some other goose. Mine was noisy and frequently dropped out like a bad phone call. After I replaced the speedometer module, it's now a much cleaner pulse train that changes frequency with vehicle speed, and it's amplitude is constant and looks like that in the link below.
Read this:
https://atracom.blob.core.windows.net/gears/2007/2007-01/2007_01_04.pdf
https://www.harleyhummerclub.org/PSOM/index.html
I had no luck finding anyone local that knew much more than reading a scanner.
I know it's possible to troubleshoot with an Android phone loaded with:
https://f-droid.org/en/packages/org.billthefarmer.scope
What it will take is making a custom "scope probe" to attenuate the PSOM levels to that approximating the microphone, and jacking it in via the phone's headset/microphone inlet.
It's hard to find good electronics guys... Nobody wants to mess with chasing electronic gremlins. But if you keep probing at it, you will find it.
Incidentally, check your solenoid wiring going into the transmission, at the transmission. These wires are exposed to some nasty environment and transmission heat, and can deteriorate in both insulation integrity and continuity. I have seen photos of stuff that made me wonder how it worked at all.
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This might be sacrilege or get me banned but here goes. There's a guy in ford-trucks.com that volunteered his services to test and repair electronics in our trucks, specifically gauge cluster, circuit boards and ecms. Here's the link:
https://www.ford-trucks.com/forums/1619612-fte-member-offering-free-ecm-repair.html
https://www.ford-trucks.com/forums/1619612-fte-member-offering-free-ecm-repair.html
Sorry for the late response but thanks for all the info . I actually found a shop locally that can test and repair the psom . Truck is still in the machine shop getting engine rebuilt . Hopefully the psom is the problem if not it's off on a hunt I go .
BeastMaster
Full Access Member
Good luck. My problems were intermittent and were traced back to three verified ( by that, I mean the situation existed ) root causes. I spent close to three years correlating misbehavior to what I could have done to cause it, fixing all three, until the last fix cleaned it all up.
Iron filings on VSS sensor.
Abraded insulation on engine tach sensor.
Intermittent PSOM output circuit. Verified by battery powered oscilloscope constantly monitoring its pulse train output to the TCU. At the underhood connector.
If yours is a constant malfunction, count your blessings. Things that show up every once in a while will drive you nuts.
Iron filings on VSS sensor.
Abraded insulation on engine tach sensor.
Intermittent PSOM output circuit. Verified by battery powered oscilloscope constantly monitoring its pulse train output to the TCU. At the underhood connector.
If yours is a constant malfunction, count your blessings. Things that show up every once in a while will drive you nuts.
IDIBRONCO
IDIBRONCO
How about your FIPL? Did you try anything with it yet?
Yes it's new as well , and calibrated , even replaced the harness to it. I read in another post it could be the third brake light out ( which it is ) or the rear differential cover . Heard anything on those possibilities ?
IDIBRONCO
IDIBRONCO
Yes. That's what Ford called it. I believe that it stood for Fuel Injection Pump Lead. If you want to get technical, I also believe that "TPS" is a GM term. Ford called it a "TP sensor" for gas engines. At least this is what I seem to remember reading in factory service manuals.
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