7.3 icp question/problem

[Superduty00]

Ok so for starters I have. 2000 7.3 6speed no chip/tuner all relatively stock engine wise
So the other day it randomly decided to crank/no start I finally got it started after cranking and cranking while holding down the pedal fired up and ran fine but starting problem continued on I thought for sure it would be ipr so I replaced it with a motorcraft one and same issue here is what I have found/tested so far
Icp while cranking stays between 250-300 and dc% spikes to 64.5

Once it finally starts icp pressure is erratic jumping between 450-750 never staying steady long enough to get an accurate reading constantly jumping and dc% is about 16.5 once it warms up dc drops to 10.9 and icp pressure still bounces but doesn't get quite as high mayhe like 650

Has no ses light no dtc codes no codes on cct injectors passed buzz test truck stumbles if icp is unplugged when running hpop is full recent oil change and oil level is good injector o rings done in last 5000 miles

Any ideas on where to go/what to check from here? And is It normal for icp pressure to jump around like that at idle? And btw all readings are from ae scan gauge
Thanks in advance need to get the rig back on the road

 

[lincolnlocker]

icp sensor is good if it changes idle. ipr can possibly be bad out of the box. but it sounds like you have a pretty good oil leak somewhere in the system

live life full throttle

 

[97f350stroker]

That high of a DC paired with low icp usually indicates a hpo leak somewhere. You can check icp mechanically while cranking to be sure that your hpop is good. If that checks out then I'd lean towards injector o-rings since you replaced the ipr already. Possibly improper install when the o rings were done and some got damaged?

 

[Arisley]

How many miles? How many miles since injectors have been out?

I am betting on injector o-ring issue.

 

[Jomax]

He has 5k on the new injector orings. What brand did you use?

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[Arisley]

Still betting on injector o-rings. Bet they find a torn one, Either that or simply worn out injectors.

The newest 7.3 is about 23 years old. We are getting into the stage of life that even a well maintained, low mile truck is simply getting OLD.

 

[Superduty00]

Used Alliant o rings
I'd say they were out about 3500 miles ago
Truck just turned 200k

 

[Superduty00]

And I Assumed ipr or something related to that for it to happen all of the sudden like that? And ideas about the erratic Icp at idle? Is that normal?

 

[Dmstrucks02]

Should hold pretty steady, it fluctuates some
DC% should be pretty solid
I'll check mine when I get off, shortly

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[Superduty00]

Ya dc stayed solid right after cold start dc holds right around 16.4 and when warm holds at 10.9 icp pressure fluctuates so much hard to get a reading on it jumps around so fast on the gauge

 

[Dmstrucks02]

Ya dc stayed solid right after cold start dc holds right around 16.4 and when warm holds at 10.9 icp pressure fluctuates so much hard to get a reading on it jumps around so fast on the gauge

Can you turn the data rate down on the gauge

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[Superduty00]

I'm not sure I haven't played with it too much it's an ae scan gauge

 

[lincolnlocker]

icp will fluctuate maybe 50psi if all is well.. you have to have 500psi cranking to fire the injectors. once started if still stockish, it will hold anywhere from 480 to 550.. dc at idle will vary. depending on how hard the pump has to work to maintain 500ish psi could be many problems. while running and hot, what is the icp and dc on a wot run?

live life full throttle

 

[mandkole]

ICP is going to jump around on the gauge-- as said, 50-100 psi is normal.

As said, starting issues likely point to an hpo leak. If its suddenly acting up since the oring change, Id pull the VCs and crank the motor over with the injectors disabled, looking for oil coming out of the poppets or the top oil ring

 

[Superduty00]

Alright just checking to see if the fluctuation was normal it jumps right to about 300 when cranking and holds about there until I hold down the acc pedal an then it will finally wanna start

 

[lincolnlocker]

Alright just checking to see if the fluctuation was normal it jumps right to about 300 when cranking and holds about there until I hold down the acc pedal an then it will finally wanna start

whats fuel pressure running?

live life full throttle

 

[Northwoods2002]

Alright just checking to see if the fluctuation was normal it jumps right to about 300 when cranking and holds about there until I hold down the acc pedal an then it will finally wanna start

And that's your problem. Start inspecting your HPOP system as you need 500 to start.

 

[Superduty00]

I haven't checked fuel pressure yet only icp pressure I'll have to check that when I get home... Ya I guess it's time to start looking into the hpo system somewhere.... Looking like it will most likely be some kind of injector issue from what you guys are saying was hoping there was something simple that I was missing

 

[Superduty00]

And I didn't see your earlier question about a wot run I took it up to about 2200 rpm in neutral under no load and icp pressure was about 1400 and I don't remember the dc I wanna say around 20 I'll double check those numbers when I get home from work I have them all written down

 

[lincolnlocker]

And I didn't see your earlier question about a wot run I took it up to about 2200 rpm in neutral under no load and icp pressure was about 1400 and I don't remember the dc I wanna say around 20 I'll double check those numbers when I get home from work I have them all written down

must be under load... not working a dang thing in neutral..

live life full throttle