Hi all, been lurking around here for a long time. Thank you for all the help in past! I have a new-to-me 02 7.3 X. Currently has 218xxx on it. I use FORscan with a plug in.

Last Monday was driving, got a low power, rough idle situation. no codes, no smoke, limped it home. Restarted in driveway, so I moved on.

Last Wed, take it out, about 1 mile into the drive, it starts up again. Try to restart it and get the condition to clear up. Took several tried before it would run with any power, got it home. This time it throws a code, p1316. Thanks to the advise here, I got into the valve covers to check the harnesses. Everything was tight and ohm'd out to spec. Put the motor back together, cleared the code and tried to start.

Motor won't start, and it gave me a new code, (forgot to write it down) but the description was a fault with the ipr. Checked the ipr end nut and electrical connection. I also checked out the wiring harness over the driver's side valve cover. Inspected for any raw wire, gave it a new wrap of electrical tape just to be sure.

Go back to the driver's seat, the ipr code is now gone, but it starts throwing p0683. Double check the harnesses, etc etc. Still no start.

I checked the fuel bowl, fuel pump to be sure I didn't have an obstructed fuel delivery. Everything checked out. Not knowing how old the CPS is, I went ahead and put a Ford replacement in. Worst case, I have a working spare. Had to take a couple days off for work and got back at it today.

Hooked up the FORscan dash, monitored ICP and IRP while cranking. ICP pressure never gets above 250-255. IPR gets to 65% duty cycle, but it took a couple revolutions for it to get there. Glow plug coil time on was 79xxx ms. I did get a new code today, p1280 and p0683 is still there. Tried unplugging the icp, still no start, and inspected the icp wiring connection, there is no oil for fluid in there.

This leads me to my questions. With the icp showing numbers that low, do I need to check the hpop? I have to assume I'm not getting 500psi to the injectors or the motor would at least start. Correct? Or, do the ipr and icp control how much pressure the hpop puts out?

I have had 4 different codes show up, and I've only replaced one part. Is there a point where I start to question the idm or the wiring harness itself?

Any wisdom you all can share is appreciated. Thank you.

 

Unplug your batteries overnight.

Clear future.

Hard codes will be set, but that should do a complete reboot and you can start with fresh codes.

See what we see.

Denny

 

I'll give it go. Thanks Denny.

 

Your IPR duty cycle climbed up to 65% because pcm is trying to get enough icp pressure to start. You need 500 psi for the PCM to start firing the injectors. Unplugging the icp defaulted the pcm to 700 psi so the injectors would activate. Since you are still not getting any start and low icp, I would first look at the ipr before you start thinking about the hpop. Bad ipr it would cause a low icp.

 

Yep, Erik is correct. I posted to your first thread in the Excursion forum with some pics to help you out.

 

Great info! Thank you gents. I will be trying all of the above. Will post back when I get this done.

 

Ok got an update. Finally got out there to work on the X, 50 degrees F, dry.

Confirmed I have oil in the hpop. Got the IRP out and rebuld it completely. Gave it a big wash out with brake cleaner and new seals.(thanks Riff Raff!) put it all back together and hooked up the batteries. Fired after a couple cranks. Pressures at ICP were approx. 1500 at idle, duty cycle on ipr was 14.5%.

Still have code p0683 that I need to figure out. I also need to splice on a new block heater plug, the original got pulled off somewhere in the past 15 years. Anyone have a wiring schematic of the plug lead? I'm not terribly electronically inclined.

So to all the crank, no start guys out there, give your ipr a look. 29mm axle socket from OReilly fit perfectly, rear taper helps to clear the metal line in the valley.

Will update on p0683 when I learn something new. Thanks again all.

 

Well, after the last post I rebuild the ipr. Put it in and it ran, was still throwing codes, but it ran. Believing that I may have overtightened the ipr on the rebuild I grabbed a new one.(motorcraft part). put it in, hooked everything back up and now it won't start again. icp oil pressure is reading 280-300psi while cranking. I have also replaced the gpcm as it wasn't ohming out well.

codes still showing are p0683 and p1280. i'm at a loss.

 

P1280 is icp is too low. Did you try unplugging the icp again and try starting? If not, try that to rule out the icp sensor as the culprit.

Since you were able to start and build enough icp before you replaced the ipr, I would take the ipr back out and inspect the orings. Maybe you pinched or cut an oring during the install?

P0683 is glow plug diagnostic communication fault. Either a wiring issue or a bad glow plug module. I would not worry about this code right now. Concentrate on the low icp because that is causing your no start. Also, you may need to clear these codes with a scanner. If they don't pop back, then they are not current codes.

 

I have tried the unplugged icp. no difference. I have started looking at all the wiring to and from the GPCM. the wiring diagram seems to suggest the the ipr receives power from the gpcm via the red wire. KOEO I have nothing at the ipr red wire, ohmed out good. I have checked the connection to the battery, all good there. My question is what is the 4 post relay looking component that sits passenger side, belt side of the GPCM? I am trying to verify that my gpcm is in fact receiving power. thank you.

 

Id'd the part in question AIH relay. Still no power to the IPR red wire.

 

Ok, my last update for the day. replaced the ipc sensor, code p1280 has cleared. new gpcm is still in, still have code p0683. truck will not start, icp pressure is reading approx. 280-300. no other codes present.

red wire to the ipr still isn't showing any power. may try manually jumping it eventually. calling it a day. thanks

 

Okay, that is a really good clue to what you should be looking at next. Here are some diagrams that show the circuit for the ipr. I high lighted in orange the Red wire to ipr. Yellow is pcm power circuit. Pink is glow plug circuit that is shared with ipr circuit. I circled items you should look at. I am thinking that pcm power relay and diode is probably okay since it seems your idm is powering up.

First check if f2.22 is blown. If fuse is okay, then to rule out the PCM relay and diode, check if you have power to fuse f2.22 with key in run position. If there is power to f2.22 then pcm relay and diode is okay.

You can see on diagram 27-4 that both red vpwr wires to the ipr and gpcm share the same fuse f2.22 and associated wiring. The two wires are spliced at S1001. Since you are having both gpcm and ipr issues, I think this power circuit is your problem

If you have power to f2.22 in run and start, and fuse is good, then you just need to start looking at the wiring and splices for broken wiring or poor connections.

 

Unplug the black connector on the gpcm and test for power on pin 9. This is the wire that is spliced to the ipr wire.

 

Wow, thank you Eric, that is some great info. I did check out Black gpcm pin 9, no power. I did ohm out between pin 9 and red wire on ipr. got good tone. tomorrow I will go through your suggested steps. Thanks again!