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7.3L Gurus Needed...Truck Running Issues

Freerider15

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Ok, so bear with me here, would love some opinions, insight, etc.

The first week of February, I took a 1500 mile round trip towing the buggy to and from SH truck ran great overall, towed great. New Full Force 1.5 injectors and KC300X shortly before the trip.

Fast forward to mid-March, and I'm picking up a Jeep with a buddy, a total of about a 150 mile round trip go. Truck running great, no issues.

We get to my place, I park and turn off the truck (still running great). I come back out about 5 minutes later so we can get it unloaded, and the truck just wants to crank. After about three long sessions of cranking it starts, but runs like it barely has ANY power. I have to basically floor it just to get it to move. This almost immediate change in behavior of the truck seems rather...odd to say the least., and no SES light.

Notes on Truck:
  • Late '99 7.3L F-350, 150k miles on the clock
  • New FF 1.5's, KC300x and Riff Raff stainless cups (~2k miles total on the setup) - At the same time, did new Alliant valve cover gaskets, Alliant UVCH's, ZD-11 GP's
  • Oil change right before the trip
  • HPx, FRx, AIS Air, etc. etc.

Troubleshooting:
  • Pulled ICP plug...very slightly oily, no difference in running (was changed out in 2015 about 10k miles ago)
  • Put in a new (Dark Blue OEM) CPS - No changes
  • HPOP and Fuel bowl not leaking - Both fully rebuild in 2015, about 10k miles ago
  • Wiggled UVCH's just in case, no change (though may look into this again)
  • I did notice my fuel pressure jump to 100psi on my fuel pressure gauge, which was odd, and then be slightly intermittent when priming a couple more times the last time I went to start it.
  • I'm in the middle of a fuel system redo with a Bosch 044 pump. Dropped the tank, fully cleaned it, and did the hutch and harpoon mods while it was out. Figured I'd clean and get the system redone as I've had stuff waiting, and rule that out here soon enough.
  • PCM check - everything seems to be working just fine. Tune for high idle on Hydra still makes it jump up some. PCM is a reconditioned one, been solid since I've put in about 5 years ago, had it programmed in person by PHP.

Some other things I've noticed/found:
- When draining the tank (jumping the fuel pump) - there was a little less than 1/4 tank in there, much of the fuel that came out was dark (e.g. oil in fuel). Now, before I changed out the injectors, I know I had some issues around this, so wondering if this is residuals just working through. That being said, popped the fuel bowl cover, and it's dark, near brand new fuel filter is dark. Normally I'd start to think injector O-rings...but the immediate change in running seems odd, and the fact that the injectors are near new, and I oiled them very liberally when installing.

Overall brainstorming:
  • Fuel pump starting to go - would possible explain the random prime fuel pressures seen the last time I tried starting it. Blockage or FPR not working as it should could cause that as well...
  • Injector O-Rings - Somehow after running great for 2k miles, and being super anal retentive on install...one or more has issues/given up.
  • IDM - I don't think this is likely, but might try plugging in a good one/reman after the fuel system is back together in case nothing changes

So, general thoughts, check, etc.? It's going to be a week or so until I can get my fuel system done (thanks to work on waiting on a few parts).
 
How does it sound? Extra knocky and loud, or kind of muted?
 
How does it sound? Extra knocky and loud, or kind of muted?

Doesn't sound knocky and loud, just like its barely running enough to not die.

Almost like (reason I'm going ahead and redoing it all), when you lean out/restrict a fuel supply.

It's basically running at 400RPM-ish.

I can give it full throttle, and normally where it would spool up instantly and rev, it sloooooowly creeps up in revs.
 
It could be bad fuel, it happens.


Check HPOP pressure at idle and under load, and check IPR values at the same time. Verify fuel pressure. Double check all your wiring for injectors, IPR, cam sensor, and ICP. Don't worry about a little oil in the ICP, as long as you have good values. Do an injector buzz test and see if you get any codes. If so then test the idm or swap it with a known good one
 
HPOP pressure is the key thing to check in HEUI systems. Your IPR should be nearly all the way open if HPOP is not high enough.

I had a similar symptom once in my 6.0 when just one of my injectors wasn't fully plugged in. Happened all of a sudden, a few years after the last time I was in there. At the time I narrowed it down to my FICM, but it was just an injector barely unplugged.

Get an OBD2 scanner and start checking what reptillikus mentioned, but if you don't have one handy, start checking your FICM connections and injector connectors.
 
Doesn't sound knocky and loud, just like its barely running enough to not die.

Almost like (reason I'm going ahead and redoing it all), when you lean out/restrict a fuel supply.

It's basically running at 400RPM-ish.

I can give it full throttle, and normally where it would spool up instantly and rev, it sloooooowly creeps up in revs.

In my experience low fuel pressure or air in the system will make it knock loudly, as will loosing more than one injector.

I would suspect low hpop pressure or a logic problem in the pcm/idm, but that is just a random ass guess.
 
It could be bad fuel, it happens.


Check HPOP pressure at idle and under load, and check IPR values at the same time. Verify fuel pressure. Double check all your wiring for injectors, IPR, cam sensor, and ICP. Don't worry about a little oil in the ICP, as long as you have good values. Do an injector buzz test and see if you get any codes. If so then test the idm or swap it with a known good one

I'll know once I get the fuel system back up on fuel pressure and that stuff.

I'll look into trying to check HPOP and IPR pressure. I've usually looked at things through the Torque App, are you talking more of a analog pressure gauge?

Double check CPS, but swapping it and checking having no change, I've pretty well ruled that out.

Torque I've heard isn't great for buzz tests, going to have to look into something else (there was another app, that I'm pretty sure I downloaded).

7.3L IDM's are general bench or in vehicle testable like the FICM on the 6.0 (as far as everything I've read). Only was to know, is plugging a good one in.


HPOP pressure is the key thing to check in HEUI systems. Your IPR should be nearly all the way open if HPOP is not high enough.

I had a similar symptom once in my 6.0 when just one of my injectors wasn't fully plugged in. Happened all of a sudden, a few years after the last time I was in there. At the time I narrowed it down to my FICM, but it was just an injector barely unplugged.

Get an OBD2 scanner and start checking what reptillikus mentioned, but if you don't have one handy, start checking your FICM connections and injector connectors.

No FICM on the 7.3L (IDM instead), and unfortunately not testable. I've got Torque and one other, but also have issues (which apparently is common on the 7.3L) to getting the bluetooth to connect. I've gotten it to before, but will need to try again.

Recommended apps?

In my experience low fuel pressure or air in the system will make it knock loudly, as will loosing more than one injector.

I would suspect low hpop pressure or a logic problem in the pcm/idm, but that is just a random ass guess.

Agreed, but I'll not rule anything out.

As far as the fuel system goes...

The oil in the tank is still of some concern. Should I get it running normal with the new fuel system (and clean) I'll see one of two things:
1.) System remains clean, and therefore likely a lot of residual in the tank (I was losing over a gallon of oil between emissions tests...a few thousand miles at most).
2.) System shows oil in it again (e.g. fuel filter/bowl) and I've got some o-ring issues
 
My hpop taking a dump made it run like it had a clogged fuel filter. Hard to start and flooring it had only a little effect on rpms
 
No FICM on the 7.3L (IDM instead), and unfortunately not testable. I've got Torque and one other, but also have issues (which apparently is common on the 7.3L) to getting the bluetooth to connect. I've gotten it to before, but will need to try again.

Recommended apps?

Torque pro and car gauge pro.

Check the injector connectors (unplug/reseat) as a quick sanity check, but if you have oil in the fuel system, yeah at least one of your injectors is bad. Check your engine oil level. Had a buddy with a late 99 7.3 lose and injector o-ring and it burned through a gallon of oil in short order.
 
My hpop taking a dump made it run like it had a clogged fuel filter. Hard to start and flooring it had only a little effect on rpms

Once I have it running (e.g. fuel system back up), i'll check on HPOP pressure. Wouldn't be a hard swap, just money I'd like to not spend :laughing:

Torque pro and car gauge pro.

Check the injector connectors (unplug/reseat) as a quick sanity check, but if you have oil in the fuel system, yeah at least one of your injectors is bad. Check your engine oil level. Had a buddy with a late 99 7.3 lose and injector o-ring and it burned through a gallon of oil in short order.

Got both of those, and also grabbing FORscan per some recommendations.

I'll double check all connections if I need to get under the valve cover, would be pretty hard for one of those to come off. If it is somehow an o-ring...going to be pretty pissed.
 
You should be able to see HPOP pressure and IPR values while cranking the truck
 
50 cent mod (wiring under valve cover) or IDM.

Diesel Tech Ron on youtube (RIP) will get you running.
 


Interesting, never seen that version before. Though, to be honest, an absolute last resort (poking harness connectors with hot tools).

You should be able to see HPOP pressure and IPR values while cranking the truck

Yeah I should, but I'll get the fuel system back in to prevent any Murphy's law stuff.

Once I've got that back in, I'll crank and see what numbers I'm getting. Did this a long time ago, but have forgotten a bit.

50 cent mod (wiring under valve cover) or IDM.

Diesel Tech Ron on youtube (RIP) will get you running.

Did 50 cent mod on previous harness, not on this one. This one has all the tabs and such in place (newer), so I'd actually have to break it to do the 50 cent mod.

I'll take a look at his videos.
 
HPOP pressure check (torque with the ford add should do it). Mine was like that when an oring popped on one injector and if they break it will happen quick. Went from running like a top to hard to start (worse when warm) and almost no top end power
 
That video above is showing the 94-98 valve cover gaskets + old style UVCH. The 99+ trucks use a single plug in the middle.

I'll know once I get the fuel system back up on fuel pressure and that stuff.

I'll look into trying to check HPOP and IPR pressure. I've usually looked at things through the Torque App, are you talking more of a analog pressure gauge?

Torque I've heard isn't great for buzz tests, going to have to look into something else (there was another app, that I'm pretty sure I downloaded).

7.3L IDM's are general bench or in vehicle testable like the FICM on the 6.0 (as far as everything I've read). Only was to know, is plugging a good one in.

I usually get the high pressure oil reading off a good scanner. Same as the IPR value. Its displayed as a percentage, so you want to make sure that youre making, say, 600ish PSI at idle with very low IPR%, and then 25-2800 PSI under load but not at more than 35% or so. More would indicate a leak in the HPOP system or a failing pump.

You can do buzz tests from some good scanners (if you know anyone who has a decent one), and then go from there. If you know anyone with an oscilloscope you could check the injector pulse coming from the IDM, otherwise yeah youre probably gonna have to send it to someone for bench testing. Or the obvious, swap it out with a buddies.
 
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That video above is showing the 94-98 valve cover gaskets + old style UVCH. The 99+ trucks use a single plug in the middle.



I usually get the high pressure oil reading off a good scanner. Same as the IPR value, its displayed as a percentage, so you want to make sure that youre making, say, 600ish PSI at idle with very low IPR%, and then 25-2800 PSI under load, but not at more than 35% or so. More would indicate a leak in the HPOP system or a failing pump.
Would higher then 2800 indicate a leak or higher then 35% indicate a leak?
 
Higher than 35%. You wanna see oil pressure in the 2000s when under load, but if the IPR has to open 75% to get there, then theres an issue with the system. A quick blip is no big deal, but you def dont want to maintain the IPR open @ 50% or more for any significant length of time
 
Sounds like injector o-rings you said there's oil in the fuel filter bowl and tank
 
I bought the OBDlink EX cable and downloaded forscan to a PC.
never plugged it into a 7.3 so I don't know what you get.

it's prety comprehensive for my mom's 2015 escape.
 
So, an update...

I got the fuel system back together finally (weather kept putting it off mainly). So now my fuel system consists of AN fittings, braided AN hose, Bosch 044 pump, pre-filter, and hutch and harpoon mods done.

Fuel pressure holds rock steady at 70-75 psi. So it's all fixed!? Nope. So not the fuel system (or at least not completely).

The truck starts up and runs, and is at least somewhat "driveable". It still cranks longer than normal (was near an instant start prior). However still a bit of stutter/rough idle, and sluggish response to throttle (e.g. I mash the throttle, and I can watch it climb slower than normal). Before this, especially with the new turbo, pretty much...mash throttle = instant spool = instant RPM jump.

Got Torque Pro running (haven't figured out FORScan just yet). Green is IPR Duty Cycle, Red is ICP, Blue is RPM.

At idle:

51167367364_5c1510f53e_n.jpg


Quick Pedal Mash:

51166589981_20fba7319c_n.jpg


Holding it at ~2k RPM:

51165922537_9e5863f633_n.jpg


51166821093_c13b4fc6a1_n.jpg


Not an SME on what numbers should look like, but my IPR% doesn't seem to be that taxing. Tomorrow I'll try seeing about getting actual numbers while doing some quick driving.

Thoughts? Any additional things to log, data to grab, etc.?

Trying to figure out next steps of troubleshooting...before taking the farkin' thing to a shop.
 
Did you ever get your hands on another IDM to swap in?
Not yet. I'll have to order one since no friends with spares, and trying to avoid the $250-$300 cost just yet.

Today I'll be using FORScan to get a better look at things and some logging, and retry with that app for and codes present.

Additionally, if I can today, I'll ohm out the injectors through the 42 pin connector to see if any are out of "spec".
 
So, I took a long "around" the block trip, maybe 5ish? miles (long straights in a square). However, something really interesting happened on the second "leg".

As I had the pedal floored, letting it build up speed (slower than normal), it kinda "kicked" as it clearing it's throat, a puff of black smoke came out...and my truck was back to normal! I had speed, I spooled up real quick, idle was nice and smooth...awesome...right!?

Wrong. I came back after the drive, and parked it in front of the shop. As a test, I thought lets start it back up as a re-check, maybe take it for another spin.

Aaaaaaand it's idling back rough/like crap, and doesn't spool up quickly (e.g. pushing on the throttle means lag in RPMs going up). However, when I do this, and let off quickly, I get a decently big puff of bluish white smoke (points to oil I believe).

I went ahead and checked codes with FORScan (cleared all and saw what came back up):

51169714905_0b39991fa9_w.jpg


My EBPV pedestal is deleted, which I would attribute (I believe) the P0470 and P0475 codes.

None of the other codes seem like anything related to the running issue (e.g. overhead console).

Here is the data logging of the run, I'm not overly attuned to what they should look like. I'm a Mech. Eng., so I wouldn't have too much trouble understanding given the right information/explanation.

51169712135_11f27efa04_h.jpg


51168848203_9ebd84425e_h.jpg


51168848188_c24596ed0a_h.jpg


51167946977_f2e60ed9f0_h.jpg


51167946972_ca99a8f214_h.jpg


51168618746_7f116643c7_h.jpg


51169712070_a8fcff081f_h.jpg


Any thoughts on the above? Help deciphering?

Felt like I was so close...it ran right again...only to be back where it was.
 
I dont really see any red flags with those graphs, but then ive never delved that deeply into anything like that before either.

Code P0470 is related to the EBPS, which you still have. Its most likely clogged, along with the tube that its connected to. It can cause defueling, but ive never heard of it causing this particular problem youre experiencing. Its in the front of the passenger manifold; there is a small stainless tube that runs up to the top of the HPOP reservoir, and the EBPS connects to it there where it is easy to access. The tube & sensor gets clogged up with soot. Both are readily available if you cant get them clean.
 
I dont really see any red flags with those graphs, but then ive never delved that deeply into anything like that before either.

Code P0470 is related to the EBPS, which you still have. Its most likely clogged, along with the tube that its connected to. It can cause defueling, but ive never heard of it causing this particular problem youre experiencing. Its in the front of the passenger manifold; there is a small stainless tube that runs up to the top of the HPOP reservoir, and the EBPS connects to it there where it is easy to access. The tube & sensor gets clogged up with soot. Both are readily available if you cant get them clean.
Yeah, I've been through the EBPS once before, cleaned the tube. Might go through it again either way at some point.
 
I can't really tell in those logs but are you measuring "desired" ICP and "measured" ICP?
 
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