ICP/IPR refresher

6speedsd · Sep 18, 2015

I haven't fooled with a HPO issue on he things in a while and to be honest I've forgotten where numbers should stand. Truck has started cutting out in the higher rpm range on anything bigger than a tow file. Engine load shows unusually low nearly all the time....less than 25% unless you wail on it, then maybe goes to 40. At hot idle ICP is 765ish, IPR 27%, ICPv is 1. Made a hard run this evening, and when it started cutting out, ICPv was like 4.5, but ICP was under 3000....something like 2700ish, and I'll say I was at probably 75% pedal. Shut truck off when I got home, went back to KOEO, and ICP is showing 173psi...wtf? ICPv is 0.2 where it should be, as is IPR at 14.7.

The cutting out makes me think it's an IPR issue, but why am I reading such a high ICP KOEO? I'll check again in the morning after a cool down. I'm thinking its time for an ICP sensor, but figured I'd get other opinions before throwing parts.

If it matters, other drivability issues, which I'm hoping at related to this issue, are very low engine load readings as I mentioned, low boost unless heavy in the throttle, shift timing is way off.

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6.0 Tech · Sep 19, 2015

Any misfire? Possibly a ficm too. Certain tuners alter the readings of the sensors to allow the.engine to work harder so its kinda hard to go off readings when dealing with a non stock vehicle. At least for load and icp voltage. Your icp reading seems od t idle, the 2700 psi t a hard pull could be normal, what rpm were you at when it was taken? When was the last time you change your oil and are you using factory filters? Also have you checked fuel pressure?

6speedsd · Sep 19, 2015

Fuel pressure holds steady at 55psi at wot.

I honestly feel like there is a slight miss at idle, but haven't confirmed that with software. That made me think about my ficm as well. Voltage is perfect on it through all checks, but I know that still doesn't rule a bad ficm out.

Oem filters and oil has maybe 2k miles on it. Rpm when it starts cutting out is somewhere between 3000-3500. Didn't look at it to be exact.

And I didn't even think about the altered icp readings with the tune. I knew that! Guess that's what I get trying to figure out something at the end of a long week with a few beers already in me!

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6speedsd · Sep 19, 2015

Readings yesterday were read with Torque Pro. Put AE on it this afternoon. Still reading 160-170 ICP KOEO. Emailed my tuner to see if he fools ICP in his tuning, and to see if maybe that's why I'm reading ICP KOEO.

Checked all my Ficm voltages again... Logic, main, vehicle power. All are reading where they should. I'm still wondering about my FICM. I still get a little haze on a cold start now even after the injector rebuilds (new solenoids, builder said spools looked great). I just assumed the haze and strong smell was because of the 30% nozzles.

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6.0 Tech · Sep 20, 2015

Could have a sticking injector, or a slight leak causing it too dump excess oil out the return. How long has it been since the injectors were gone hrough? I guess there is a chance too that you have an input problem such as a cam or crank sensor causing it to cut out too. I had a 7.3 in the shop about a week ago doing something similar and it was the cam sensor. Granted too i could be sending you on a wild goose chase an it is all centered around the slight misfire... does it crank over even?

6speedsd · Sep 20, 2015

Been about a year since injectors were gone through....maybe 10k miles on them. It's weird because other than cutting out, it runs fantastic. Like I said, boost is a bit low, and it's screwing with some of my shift timing, but I think that is all related as the pcm isn't reading much load for whatever reason.

9 times out of 10 it'll fire off by the 3rd revolution. It's smooth, not rough, not choppy. Every now and then it'll be slightly longer on a crank, but it's never what I'd call a long crank.

Far as I know, CMP and CKP are both original to the truck, although I've never thrown a code for either.

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6.0 Tech · Sep 20, 2015

Can you watch a graph of your icp ressure with your scanner? See if its bouncing around a lot, if it is, you probably need a hi pressure pump.

6speedsd · Sep 20, 2015

I have...really not bouncing around. Maybe up or down 30-50psi at the most.

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6.0 Tech · Sep 20, 2015

I had a 6.7 cutting out intermittently on a tow une, guy wouldn't do any higher han that on it. It turned out it was the tune. Possibly call your tuner and see if maybe they can re send it to you. Maybe it got corrupted somehow. You switch tunes a lot?

6speedsd · Sep 20, 2015

I really don't. Stays on my tow tune 99% of the time. Decided to load street up and have a little fun over the weekend. That's when this started.

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6.0 Tech · Sep 20, 2015

It could be a corrupted street tune then. If its not setting any codes, and everything you.ve checked checks out, i'm at a loss now. Sorry...

6speedsd · Sep 20, 2015

Still waiting to hear back from the tuner about the way he tunes/fools ICP. I have a race file from a different tuner that I rarely use...might load that and see how it acts in the upper rpm range.

Thanks for the help

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