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1997 Ford F250 HD 7.3 Diesel 4x4 ,4EOD trans, Upgraded Alternator, Western plow relay,
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Discussion Starter · #1 ·
Hi my fellow power stroker's i do not know if i posted this in the right thread but im sure it will be moved if it wasnt. With that out of my way i have a conundrum for yawl.


So i Recently bought this 1997 7.3 Powerstroke F250 from someone.... it had codes on it but i figured them out but what i cant figure out is why there is one code that is persistent on the truck itself

the code is p1395
I have replaced the gpr twice while under warranty
I replaced the passenger side glowplugs all of them ( i heard i could change 1 side all of them without effecting the other)
I have ruled out the Alternator
I have ruled out the wiring both out of the valve cover and inside it
i have also ruled out the batteries

I have a hunch its the pcm but i don't know how to test it and if i do do i need some special tool to do so or can i accomplish it with a voltometer and a scan tool Any answers are appreciated
 

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Is this a California truck?
 

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IIRC there were a couple of changes on the glow plug system for the California version. I think the biggest difference was the addition of 2 shunt resistors and a pair of feedback wires that would allow the PCM to sense how much current the glow plugs were using. Idea being, if one glow plug burned out the PCM could sense that and set a code. Looking at my favorite haunt for codes it states: P1395 Glow Plug Monitor Fault Bank No. 1. I read this as there may be a problem with the sense wire or the input on the PCM. Unfortunately, my wiring diagram is 49 states... Perhaps wiser heads will reply as well.

Cj
 

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1997 Ford F250 HD 7.3 Diesel 4x4 ,4EOD trans, Upgraded Alternator, Western plow relay,
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Discussion Starter · #5 ·
IIRC there were a couple of changes on the glow plug system for the California version. I think the biggest difference was the addition of 2 shunt resistors and a pair of feedback wires that would allow the PCM to sense how much current the glow plugs were using. Idea being, if one glow plug burned out the PCM could sense that and set a code. Looking at my favorite haunt for codes it states: P1395 Glow Plug Monitor Fault Bank No. 1. I read this as there may be a problem with the sense wire or the input on the PCM. Unfortunately, my wiring diagram is 49 states... Perhaps wiser heads will reply as well.

Cj
[/QUOTE

The wire leading to the pcm could be the culprit if i didnt know that the owner before me replace all the wiring above the valve cover. So with this truck being a california one ur saying it could possibly be the shunt throwing the code for no reason? And yes hopefully more respond thanks for yours
 

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It could be that the PCM input is damaged. Are there safety/emissions inspections that you must pass? If the truck runs fine otherwise... and you don't have to worry about inspections keeping the truck off the road, I'd just drive it.
 

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1997 Ford F250 HD 7.3 Diesel 4x4 ,4EOD trans, Upgraded Alternator, Western plow relay,
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Discussion Starter · #8 ·
Update: The truck does not run rough or idle rough at all either
Forgot to mention that when I'm going down the road it happens intermittently but some times the power would throttle back and then go back to normal when I hold the gas pedal going reg speed
 

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1997 Ford F250 HD 7.3 Diesel 4x4 ,4EOD trans, Upgraded Alternator, Western plow relay,
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Discussion Starter · #9 ·
If the PCM input is damaged is the input back behind the firewall and if so how in the blank would I get to it don't tell me I'd have to rip out the dash in the truck in order to get to it not saying that I wouldn't do it but
 

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Hmm... Intermittently you say? That sounds more like a loose connection or a wire that is broken/on its way out. There really isn't anything on the inside of the PCM that would behave intermittently - it either works or it doesn't (although I have seen one or two ICs that failed slowly, but that is rare). The PCM is mounted midway down in the firewall on the driverside to the right (if you are standing in front of the truck looking back) of the master cylinder. There are three connectors down there: a small one on the left - body wiring, a big rectangular one in the middle - body wiring, and long skinny rectangular on the right - PCM. You access and remove the PCM from the engine bay side. It helps if you pull all of the plastic doohickeys and loosen any bolts that attach the plastic wheelwell to the fender and frame. Pull the wheelwell down and forward and the PCM will then side out toward the front of of the truck (perhaps with a few choice words to help it along). I would not expect a glow plug issue/DTC to cause a loss of power while driving. Do you have something that can track and record PID data? If not, I recommend the following:
"I would recommend that you first invest in FORScan (forscan.org) and a suitable adapter. I have an OBDLink EX usb adapter (should you wish to use a computer to collect data), or take a look at either a BAFX or OBDLink unit. Both BAFX/OBDLink have a bluetooth/Wifi units (there are a few folks around here that recommend them) that will would work with a smart phone (Run of the mill box store scanners and even a great number of the higher end scanners can't touch these trucks as Ford used the "heavy duty diesel" protocol for communication). Once you are setup I would capture data.. At minimum I would save RPM (really this is CPS), ICP, IPR, MAP, EOT and IVS (at least I think that is the PID for the go petal). FORScan will allow you to save the data as a .csv file which you can import into excel. The information you get from the truck will help identify what your problem really is without just "throwing parts" at the truck."
On the Oscilloscope page you can record the live data to look at later. Just make sure to connect before driving anywhere - as connecting causes a momentary interruption. I typically put the key in run, connect FORScan, start recording and then start the engine.

Cj
 

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Discussion Starter · #11 ·
There is no inspections I have to pass. Looked at pcm input connection on there's no sign of anything wrong is it possible the code could have burned into the PCM if it wasn't dealt with right away or is that a bunch of hog wash
 

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Your problem is not likely to be found at the PCM connector... it will be in the wiring loom somewhere. I would liken the problem to your favorite corded drill with a bad cord - if you wiggle the cord just right the drill will run, but if you twist the drill the wrong way it stops. I don't think the code would "burn" into the PCM. These older PCM's are limited on what and how they can store information.
 

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The FORScan link didn't work? Odd, when I tried it just now it did fine. As for your videos - In the cab video... Idle sounds good I don't hear anything that sounds off. Outside the truck - There is a buzz or a rattle (kind of sounds like a far away chainsaw winding up) that I can hear over the idle noise. I'm not sure what it is, but it is cyclic One thing to try - disconnect the accessory belt and idle the truck without it. Perhaps one of the accessories/pulleys has problems. Pay close attention to the fan - tug it side to side and in/out.
 

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IIRC IPR screens were removed in in the 96 model year. So your 97 won't have one. The IPR is an actuator designed to control the oil pressure. The more pulse width it is given the more it closes and drives the pressure up in the high pressure oil rail. The ICP is the sensor that reads and reports the oil pressure that is in the high pressure oil rail. You can unplug the ICP and the PCM will default to a look up table. Engine won't run optimally.
As for the throttle problem you mention in post 8... Could also be the TPS (throttle position sensor) is beginning to fail and has a dead spot. However, I'm kind of guessing at what is wrong without having reliable data from the PCM. Really need to see what the RPM (really this is CPS), ICP, IPR, MAP, EOT and IVS are doing relative to each other. What scanner are you using to get codes?
 

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Discussion Starter · #18 ·
I'm just using a regular OBD2 craftsman scanner scan tool is there another record data from the truck other than that forescan it's not the fuel bowl sensor And apparently it can't be the IPR because if it was it would fail and the truck wouldn't start. So either it's a bad PCM or like you said it's a bad sensor probably on the throttle body or something because I do have a throttle body
 

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If your truck is a diesel it will not have a throttle body. Perhaps you could take a picture of your "throttle body" and post it (the 6.7 has a throttle body - but it is only used to help pull EGR gases into the intake). The 7.3s (and really any diesel) are "throttled" by how much fuel is injected. The craftsman scanner you have seems to pick up the PIDs - and the engine codes. I'm wary about box store scanners correctly reading the PIDs and codes from the 7.3 diesel engines. I just helped fellow who's box store scanner was giving him completely bogus codes - for parts that don't even exist on a 7.3. Can you scanner record and save the data stream? I always thought that box store scanner only show you the live data. Here is a screen shot from the oscilloscope function in FORScan:
Colorfulness Slope Font Pattern Screenshot

FORScan allows you to save data and open up the files later. It is really helpful as you can go back and look through the engine data to see what is happening at any particular moment. If you have a bad sensor, you will be able to comb through the data stream until you find where it went wrong. The graph will be super helpful in finding what causes your power dips. There are no sensors on the fuel bowl that report live varying information back to the PCM.
 
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