When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
My truck is giving me the p0321 fuel secondary circuit low. Last night I went to leave home drove about 200 ft then had to back right up as the truck was dying running rough. Since then I have checked the IPR tin nut it was tight. There was a small insulation tear on the wire as well however the copper wire was intact. New pigtail will arrive Monday. IPR was replaced few years ago with a Ford unit. Currently in the truck and of course it’s driving ok And I am unable to get the code to reappear. Previously, every time I cleared it it would immediately come back. Current oil temp is 175 when my IPR was bad the truck would shut down around 160 every time. Anyhelp would be greatly appreciated.
Thanks
Just want pedal to the metal a couple times could not trip the code back on
Restarted the truck just now the code is back taking it on an errand
Do you have a way to check fuel pressure? This P0231 code (didn't see a P0321 code in the DTC list for our trucks) could indicate the fuel pump is toast, or not getting power.
The fuel pump was recently changed with a bosh unit I may be incorrect but I think these codes are related to the IPR and the wording is confusing. A taxi is en route and I’ll plan on returning with the gear to run a fuel pressure gauge off the drain valve.
fuel pump fuse appears good as well as the IDM fuse. Just had someone turn the key to the on position could not feel the fuel pump running. However after about 20 seconds it made the noise is usually does coming from the engine bay not sure how to describe that but if you have changed the fuel filter and reprinted the system you’ve heard the noise before.
Currently the truck went from not turning on to running rough/non drive able.
From your profile, looks like you have an '02. The attached schematic might help - if it's fuel related and not the IPR. Interested to see what you find with your fuel pressure check.
Yes it is an 02 which means the fuel
pump relay is Built into the fuse box....
There is a video saying it can be bypassed but at 2mins 30 seconds there was not enough information.
Could it be possible to undo the two leads lead going to the pump secure them. The run new leads and have the fuel pump turned on by my auxiliary switches which are protected by fuses and relays?
I would be looking to do that as a temporary repair keeping me on the road until I can get the new part.
It looks like Jeff has you going down the right path to getting the truck running right again. As you progress down that path, you can check the fuel pressure somewhat easily and cheap by using the method noted in the 7.3L PSD Tech Folder and pasted below. This will give you solid and visible data instead of going by feeling the pump for vibration.
Yes it is an 02 which means the fuel
pump relay is Built into the fuse box....
There is a video saying it can be bypassed but at 2mins 30 seconds there was not enough information.
Could it be possible to undo the two leads lead going to the pump secure them. The run new leads and have the fuel pump turned on by my auxiliary switches which are protected by fuses and relays?
I would be looking to do that as a temporary repair keeping me on the road until I can get the new part.
That should work - looks like a number of folks have done that to get 'er going again.
Went back to the truck made it a whole 25 ft before shutting her down. Did not get a chance to check fuel pressure but based on the sound of the truck and not hearing or feeling any motion from the pump it’s low. If it is the relay I can have it repaired for 265 w overnight shipping included or I can buy a whole box for 420. With 285k on the truck I’m not sure which is the better option long term just the cheaper one lol Additionally not sure id be increasing reliability by installing the whole
box which would be the purpose of spending extra loot. Since it doesn’t seem like a lot of these trucks break in this area.
Went back to the truck made it a whole 25 ft before shutting her down. Did not get a chance to check fuel pressure but based on the sound of the truck and not hearing or feeling any motion from the pump it’s low. If it is the relay I can have it repaired for 265 w overnight shipping included or I can buy a whole box for 420. With 285k on the truck I’m not sure which is the better option long term just the cheaper one lol Additionally not sure id be increasing reliability by installing the whole
box which would be the purpose of spending extra loot. Since it doesn’t seem like a lot of these trucks break in this area.
Before I dropped that kind of coin I'd at least check if the pump is getting power and how much. Ironically I had a fuel pump problem myself yesterday. Truck was idling in the drive warming up and I heard it go to high idle then nothing. I cycled the key no hum from the pump or pressure on gauge. Immediately reached for the multimeter. Voltage was good ended up being a bad connection.
I took the lazy route and built this test harness. The fuel
pump turns on now every key cycle and the truck runs rough still getting the code however this is definitely not the best connection holding the wire to the pins. The add on fuse goes in the box with the red and green lines connected as one, blue to the PCM ground w 5 amp fuse and yellow to the fuel inertia switch
Up and running with the 99-01 7.3 upgrade lol!!! At first there was a problem because I only had one 20 amp fuse installed in the add a fuse circuit. Once I doubled that up the problem went away immediately.
I appreciate the reply’s and know I went a little out of order, could not find my fuel pressure test kit and have the new one arriving today. Then once I realized I’d have to change up and dive into mud to check the fuel pressure voltage it became easier for me to just make the harness worst case something to test the problem best case fix the issue.
If it works run it I say, as long as it's not a danger to others. Because nobody tends to care if someone burns to a crisp, electrocutes, or otherwise maims themselves doing something questionable. Done quite a few MacGyver esque roadside repairs myself through the years.
