Irregular idle revving up and down VIDEO & Update!

[young7.3]

Anyone seen this before? Is this an issue with the ipr?


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[6.0 Tech]

Anyone seen this before? Is this an issue with the ipr?


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It could be the ipr, tuning, or icp. Is it something that just started happening, or did you make changes, such as injectors and tune and then it happened?

If it started happening with no changes to anything, check your icp voltage at koeo, it should be .23v, also, unplug it and make sure there’s no oil in the connector.


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[young7.3]

It started without any changes to the truck.

ICP voltage koeo is .22 volts.

Ipr connector has a little oil on the outside of the male connector. Not enough that its dripping.

I have a spare IP sensor, I just need to get the socket for it.

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[Iso-baric]

Any chance your headlights are flickering in time with engine speed (slower at idle, faster as engine speed increases)?

I had a similar issue recently. Started as a small hiccup at idle or at ICP less than 1300 psi. Progressively got worst until engine started hunting similar to yours at idle.
Went through all of the usual suspects - swapped known good ICP/IPR/CPS before I noticed the headlight flicker one night.

Must have had a bad diode in the alternator causing havoc on the electric side. 5min with the multimeter, and a new alternator later I was back in business.

 

[young7.3]

I don’t think it’s headlight flicker. I’ve had the headlights off this entire time.

I did some testing and got some very weird results. Put a brand new motorcraft ipr sensor in and torqued it to proper spec. Now the truck idles just fine but there is zero power until the icp duty cycle hits 45% and at that high of duty cycle pressure is only 1000/1400 psi. That isn’t even the weird part.

At this point we are around 60-70% wot. Then it’s like someone pushes the nitrous button and the truck takes off! Has full power, full boost, everything!

The only item i changed was the ipr sensor. I get the same results in every tune and even in stock mode.

To throw another wrench in things i have a cps and oil pressure fault codes.

Any ideas?

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[6.0 Tech]

I don’t think it’s headlight flicker. I’ve had the headlights off this entire time.

I did some testing and got some very weird results. Put a brand new motorcraft ipr sensor in and torqued it to proper spec. Now the truck idles just fine but there is zero power until the icp duty cycle hits 45% and at that high of duty cycle pressure is only 1000/1400 psi. That isn’t even the weird part.

At this point we are around 60-70% wot. Then it’s like someone pushes the nitrous button and the truck takes off! Has full power, full boost, everything!

The only item i changed was the ipr sensor. I get the same results in every tune and even in stock mode.

To throw another wrench in things i have a cps and oil pressure fault codes.

Any ideas?
View attachment 187557


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Figure out the cam sensor code, that will do all sorts of goofy shit. These trucks are old as hell now, could be frayed wires at the cam sensor, or a cam sensor. That 1211 code could be causing issues as well. Check fuel pressure, typically the culprit for that code.


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[fastersteve]

How are the batteries? Every time I've seen crazy codes like that, one of them has died. These trucks are very sensitive to low voltage.

 

[young7.3]

Batteries are not even a year old. Interstate batteries manufactured on 2/24. Truck cranks over and starts strong.

If I installed a new working ipr sensor, then why would I have this really weird performance issue now? Just doesnt make sense. What are the odds I got a bad sensor from Ford?


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[Iso-baric]

I don’t think it’s headlight flicker. I’ve had the headlights off this entire time.

Headlight flicker was a symptom in my case, not the cause. Root cause being dirty voltage output from the alternator due to a diode failure.

Any sensor that uses a 5v reference can be effected by 'noise' in the 12v system - ICP/CPS/MAP/EBP etc.

It takes <5min to do a diode test if you have access to a multimeter. Or you can simply disconnect the hot wire from the alternator and run the truck for a short period of time to see if the issue persists.

 

[young7.3]

Oh I see what you are saying now. I have a mutlimeter. Can you explain the diode test?


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[young7.3]

Figure out the cam sensor code, that will do all sorts of goofy shit. These trucks are old as hell now, could be frayed wires at the cam sensor, or a cam sensor. That 1211 code could be causing issues as well. Check fuel pressure, typically the culprit for that code.


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I’ll look into the codes more as the cps one is definitely new. Fuel pressure is good. I have a gauge under the hood and its set to 60psi. I dont have large injectors so im confident pressure isnt dropping under throttle.


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[6.0 Tech]

I’ll look into the codes more as the cps one is definitely new. Fuel pressure is good. I have a gauge under the hood and its set to 60psi. I dont have large injectors so im confident pressure isnt dropping under throttle.


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Was there oil in the icp sensor? Did you change the pigtail? I can’t tell you how many times I’ve gone full retard and got 2 wires switched around when changing pigtails


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[young7.3]

It was the ipr sensor that I changed. But i did remove and check inside the icp sensor connection. There was a tiny amount of oil. I cleaned the contacts with contact cleaner and connected it back.


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[young7.3]

I have a new dark blue cps on the way. Will swap it out saturday and give that a try


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[Iso-baric]

Oh I see what you are saying now. I have a mutlimeter. Can you explain the diode test?


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https://electrical-engineering-portal.com/digital-multimeter-testing-car-charging-system

Test #3 and #4 towards the middle of the page.

 

[young7.3]

I put a brand new cps sensor and it cleared the code i had, but truck stills runs the same.

Here’s a graph with icp and dc% to help explain whats going on.

View attachment ICP and DC Graph.pdf


I’m going to do the electrical test above and then my last idea is to put the original IPR back in.


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[young7.3]

Bump


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[young7.3]

I wiggled the icp sensor the other day and the truck died. Thought it was a bad connection so i put a new pigtail on but still no dice.

I did unplug the icp sensor and started the truck. The scan gauge showed something crazy like 65000 psi. I assume this is an error on the output reading?

My next attempt is to put the original ipr back in.


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[6.0 Tech]

I wiggled the icp sensor the other day and the truck died. Thought it was a bad connection so i put a new pigtail on but still no dice.

I did unplug the icp sensor and started the truck. The scan gauge showed something crazy like 65000 psi. I assume this is an error on the output reading?

My next attempt is to put the original ipr back in.


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If wiggling the icp messed with it, I’d guess you’ve got a 5v issue. Wiggle the harness around the icp, see what happens. Your 5v sensors are icp, ebp, map, baro, cam sensor, and app. It will run with everything unplugged, except for the cam sensor. Chase these sensors, particularly the ebp, icp, and cam sensor, as they’re all on the same harness, and the split offs for the ebp and cmp are close to each other, and probably fairly near the icp split off. The app, baro, and map are all on the body harness, but are still using 5v, it would more than likely be a different in on the pcm, but I don’t have a wiring diagram in front of me to verify. The sensors all on the engine will share a 5v pcm pin and a signal return pin, but have different signal pins.


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[Iso-baric]

Any chance you've had the 42-pin connector at the PCM off recently? I agree it sounds like you are having a 5v issue - whether it be a pushed pin or wiring break.
I'd grab a multimeter and ohm between pin 21 (+5 VREF) and the ICP sensor (at least in the diagram I have this is the last sensor in the chain) while someone else unplugs sensors / jiggles harnesses.

Here is a good link with schematic / pin outs.

Wood-N-Things - Wiring Diagrams

Colored Wiring Diagram Download 2002 42 Pin Connector Pinout 2002 Superduty Wiring Diagram Manual What's new for 2002 Superduty 2002 Superduty Exterior Lights Wiring Diagram Springerpop's 2000 Wiring Diagram Injector System Wiring Diagram #1 Injector System Wiring Diagram #2

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