ICP is lying to PCM

[Shaw]

I put a set of 350 / 400 in the truck and I have been having trouble getting it to idle and longer cranking time then I think it should. No matter what I did with the ICP at idle it didn't make much of a difference. I have my 2nd hpop off and im just running a single till I get this figured out.

I hooked a mechanical gauge to the port at the back of the hpop. I found it to be reading a little over 200psi more then the programming is calling for. It should be around 725psi at idle but is at 925psi. AE says it is at 725psi. I also noticed the idle would stick around 1000 rpm. When it did this the icp would stick at 1050psi and hold for a second or two even tho AE said it was at 725psi. (this was what made me think to put a gauge on it)

I made 4 tunes to try. The only difference being ICP going down 100psi on the first two and 50psi on the other two. Basically the first one dropped gauge to 825 and AE to 625, second tune dropped gauge 750 and AE 525, the last two made no difference with mechanical gauge but dropped AE to 425psi.

I replaced the ICP sensor, it made no difference. Replaced the ICP regulator and no difference. I then pulled the check valves out to see if maybe they were the problem. No luck. At this point I don't even know what to do or check.

 

[fbilly420]

you should install your mechanical gauge in the oil rail in one of the heads. That is where the ICP sensor reads. Maybe it is different at the head.

 

[TARM]

I agree you need to see the oil psi at the same location as the ICP sensor. Pull the next oil plug down in that same rail and see what you get.

400% nozzles from everything I am told by those tuning them take some very precise changes to get them idling well. MAybe shoot 907Dave, Bill or Matt etc a PM and see if they can give you some settings to try and ranges to play in.

 

[Shaw]

The hanging up seems to be taken care of with the new regulator.

I can try the gauge in the same rail, but I'm not sure how it would be any different. With the check valves out of the pump it should now all be the same, or I would think anyways. I will move it tomorrow and see what happens.

I don't think I will have to much trouble dialing in the idle once I get the hpo to do what I want it to. It's just kind of hard when you are shooting in the dark with what the icp is going to be at, or stay at. When I first put them in I was able to get them to idle perfect but it only lasted for about a week. I think that is when something happen to the hpop.

Here is a video of the first day I put them in. They idled pretty good, needed some fine tuning but pretty good over all.

YouTube Video

 

[Shaw]

Moved gauge to left bank and no change. Still reads different then ICP sensor / AE.

 

[TARM]

Maybe the gauge itself is off. You changed ICP sensors and got the same thing. But nothing has been done to confirm the manual gauge is reading correctly. Seems to me I would be questioning the manual gauge.

 

[Shaw]

I thought the same thing yesterday too, so I switched it with a brand new liquid filled 0-5000lb gauge. Made no difference.

I was able to get it to drop to 600lbs on the gauge by making my tunes 375lbs at idle thru the PCM. The funny thing is it would just creep right back to 750lbs on the gauge while AE kept it between 375 and 400.

Another thing I tried was to unplug the ICP and it made no change, none. Gauge just sat rock solid on 750, I didn't think to look and see what AE was reading.

I guess tomorrow I will pull my chip and see what the readings are stock?

 

[TARM]

What HPOP are you running?

What is your setup for IPR/s?

What are you seeing for IPR duty cycle % and voltage?

It almost is sounding like the the IPR can not dump enough oil to keep pressure down where it needs to be.

By what you are reporting it seems that AE is seeing only what the program is calling for and not the actual. I know that it reports actual when its below whats called for and I personally have not see it report higher than called for as I have not had a issue like that. I wonder.........

 

[TARM]

What brand ICP sensor? Motorcraft or some china knockoff? I know I have seen people go thru a number of ICPs before they get a good one when using offlabel and they tend to go bad sooner. The reason I ate a big bullet on price and went with straight motorcraft for the ICP IPR and will for any sensor that goes bad accept the CPS which I only use Delphi brand.


Something is up. I wonder what someone like Golfer has to say. Also have you asked Bill@ PHP since your runing your own tunes. Maybe he has seen stuff like this.

 

[Shaw]

Tarm,
both are Motorcraft bought from Ford, both were brand new.
HPOP is stock
IPR is stock

With chip gauge 910lbs - AE 661lbs / 13.28 Duty Cycle 1.04 volts

No chip (nothing was very stable) gauge 725lbs - AE 480lbs / 9 Duty Cycle .81 volts

At this point if no one has any other suggestions I'm going to pull the mechanical gauge and put it on another truck to see if it matches what AE says on that truck.

 

[TARM]

Thats a good idea. Then at least you know if its normal or not. That would be something if it was.

 

[Groomzybanshee]

Possible you got the ebpv plug and ipr plug
Mixed up?

 

[Shaw]

Possible you got the ebpv plug and ipr plug
Mixed up?

Nope, but the thought crossed my mind too, so I double checked it.

 

[TARM]

I am interested to see what you get from the other truck. Either way

 

[Shaw]

Well, I put the mechanical gauge on our excursion and its the same thing, off by 200 psi. It has to be the gauge / gauges (I bought them both at the same time). Im going to get a hold of the place I bought them from and see what they have to say.

Since the pressure isn't the trouble and i have lost the ability to get the thing to idle worth a damn I started tearing into it and I think I found the trouble -

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The engine harness rubbed on the valve cover and now some of the wires are grounding out on the metal and each other. Just from me pulling the harness away, and separating the wires from one another. Its acting better.

Thanks for everyone's help!!!

 

[TARM]

Sometimes its the simplest of things. I was carefully checking mine as I was hooking everything back up today to finally get the old girl fire up again after this last round of upgrades and fixes. I want to get everything wrapped that the wire loom doesn't cover.