How To Measure ICP

windrunner408 · Dec 4, 2011

I am wondering how or what can I do to accurately measure/monitor my ICP?

My truck is tuned with a stock 48v FICM. However, I plan to upgrade to a 58v tuned FICM very soon.

I understand that my CTS will not accurately display ICP with a tune on my truck, so I need to go back to stock to accurately read it or install a HPOP gauge that piggy backs off the oem sensor.

Well what about with a tuned FICM?? I have heard that if my FICM is tuned that even a "piggy back" gauge will not accurately read ICP. So how do we do it? Can I install another oem sensor and plug a HPOP gauge into it (if I get a plug and wire it to the gauge)??? Any info would be great.

strokin6L · Dec 5, 2011

you still wont get it to read correctly with a tuned FICM by getting the reading from the OEM sensor. I'm getting my HPOP reading from the OEM sensor with my HPOP gauge and it wont read over 1560psi when engine is warm and up to temp even if i floor it. However, when i turn the truck back to stock...it will them read ICP like it should. I've tried a few different HPOP gauges and all have done the same exact thing with a tuned FICM with a tune and when stock. The most accurate way i think is that you need to install a hard gauge and get the reading right from rail.

windrunner408 · Dec 5, 2011

strokin6L said:
The most accurate way i think is that you need to install a hard gauge and get the reading right from rail.

This is what I want to do and was asking about. How do we do this?? I dont think the aftermarket gauges come with sensors. I think they just piggy back off the oem sensor. Could I just get an oem sensor and a plug and hook it to the gauge to read ICP actual??

6.0dirtworker · Dec 5, 2011

What about reading volts instead. Pretty sure a wot run is 4.7v

strokin6L · Dec 5, 2011

windrunner408 said:
This is what I want to do and was asking about. How do we do this?? I dont think the aftermarket gauges come with sensors. I think they just piggy back off the oem sensor. Could I just get an oem sensor and a plug and hook it to the gauge to read ICP actual??

i don't understand why you would want to use the factory sensor if you installed hard gauge and got the psi reading right from the rail. Just find a pressure sensor that can read that high of pressure...screw the factory sensor if you go that route. The factory ICP sensor is a voltage sensor. When installing a HPOP gauge and getting the reading from the factory ICP sensor, the aftermarket gauge receives the voltage from the sensor and turns it into a PSI reading.

strokin6L · Dec 5, 2011

Monstar said:
What about reading volts instead. Pretty sure a wot run is 4.7v

I still don't think it'll work with a tuned FICM tho. If it did...i would think that all of my HPOP gauges that i've tried would've read right if it was getting the voltage reading from the ICP sensor and the HPOP gauge displaying that voltage in a PSI reading. I think the tuned FICM screws up the volatage and PSI readings for all the electric HPOP gauges and even getting them from the OBDII port.

Redneck6.0L · Dec 5, 2011

get a icp gauge from isspro or autometer, they pull the voltage off the back of the icp sensor, the tells the truth

Redneck6.0L · Dec 5, 2011

no matter what ficm or tuner you have in the truck

windrunner408 · Dec 5, 2011

strokin6L said:
I still don't think it'll work with a tuned FICM tho. If it did...i would think that all of my HPOP gauges that i've tried would've read right if it was getting the voltage reading from the ICP sensor and the HPOP gauge displaying that voltage in a PSI reading. I think the tuned FICM screws up the volatage and PSI readings for all the electric HPOP gauges and even getting them from the OBDII port.

First things first. Every electric pressure gauge (oem or aftermarket) works off of changes in voltage. The only way to get away from that is by going with a mechanical gauge.

Unless I am wrong here, the FICM only sends a reference voltage to the ICP sensor for voltage output of the ICP sensor to be compared to for converting to a pressure reading. I dont understand how a tuned FICM would affect that.

Redneck6.0L said:
no matter what ficm or tuner you have in the truck

This makes sense to me and should be right.

strokin6L · Dec 5, 2011

Redneck6.0L said:
get a icp gauge from isspro or autometer, they pull the voltage off the back of the icp sensor, the tells the truth

I used both ISSPRO and autometer and they never displayed the PSI correctly. Never got much over 1500psi with the race file. I turned the truck back to stock...then all of a sudden the psi reading would read the way it should. Contacted eric and he told me it was because of the tuned FICM...so idk.

Cutting-Edge Diesel · Dec 5, 2011

I have a tuned ficm and my isspro reads fine

windrunner408 · Dec 5, 2011

I would be interested to know how a tuned FICM supposedly affects ICP voltage. Chris do you remember why Eric said a tuned FICM would cause an ICP gauge to not read accurately. Also by "tuned" are you referring to just a tuned FICM or a 58v and either tuned or not tuned. Basically did Eric say all non-stock FICMs (tuned 48v, 58v, and 58v tuned) would cause ICP to display accurately.

Keanoknick · Dec 5, 2011

Doesn't someone make/sell a pigtail/adapter to plug into the ICP sensor, to hook an Isspro guage to, so that we don't have to cut and splice wires into the factory harness.

strokin6L · Dec 5, 2011

Keanoknick said:
Doesn't someone make/sell a pigtail/adapter to plug into the ICP sensor, to hook an Isspro guage to, so that we don't have to cut and splice wires into the factory harness.

the pigtail comes with the ISSPRO gauge. But you can also get one from strictly diesel http://shop.strictlydiesel.com/store.php/products/Driven_HPO_Pigtail

strokin6L · Dec 5, 2011

windrunner408 said:
I would be interested to know how a tuned FICM supposedly affects ICP voltage. Chris do you remember why Eric said a tuned FICM would cause an ICP gauge to not read accurately. Also by "tuned" are you referring to just a tuned FICM or a 58v and either tuned or not tuned. Basically did Eric say all non-stock FICMs (tuned 48v, 58v, and 58v tuned) would cause ICP to display accurately.

I'm referring to a tuned FICM not a 58v FICM. I have eric's moderate tuned FICM. I wish i would've saved the emails from eric when i was talking to him about it. But if i remember correctly...i think he said it had to do with the SCT tuning with the tuned FICM. I've talked to a bunch of guys with the same problem. Some have the ISSPRO and some have the autometer...and have seen the same thing i was seeing. I'll see if i can find some threads

windrunner408 · Dec 5, 2011

I think I am going to go with the ISSPRO gauge. I like the look of them.

Extended Power · Dec 5, 2011

The ICP pressure will not be accurate if trying to read it through the OBD2 connection when running tunes....as in trying to use AE software.
The gauges work fine, because they are straight off the sensor.

windrunner408 · Dec 5, 2011

strokin6L said:
I'm referring to a tuned FICM not a 58v FICM. I have eric's moderate tuned FICM. I wish i would've saved the emails from eric when i was talking to him about it. But if i remember correctly...i think he said it had to do with the SCT tuning with the tuned FICM. I've talked to a bunch of guys with the same problem. Some have the ISSPRO and some have the autometer...and have seen the same thing i was seeing. I'll see if i can find some threads

That would be great if you could man. I am very curious as it doesnt seem intuitive that it would do that. I could possibly see it with a 58v FICM as the voltage in that FICM is higher I still think that either a 48v or 58v FICM probably uses 12v as the reference voltage. Have you tried just hooking up a voltage meter or gauge to see if you are truely getting 0 and 5v at each extreme? I would be curious to know. That would at least tell you if it was in the FICM or your gauge.

Keanoknick · Dec 5, 2011

strokin6L said:
the pigtail comes with the ISSPRO gauge. But you can also get one from strictly diesel http://shop.strictlydiesel.com/store.php/products/Driven_HPO_Pigtail

Thanks, that's exactly what I was looking for.

strokin6L · Dec 5, 2011

I found a thread on powerstroke.org that i posted the email i received from eric...here it is
Here's what he told me: "Are you running a tuned FICM? If so, that's why. With physical upgrades, that's the way it is. The high power tuning makes a lot more power, but the lower power tuning sometimes backs down the power to keep it safe. Less timing, etc.

Stock, you should be seeing 3600+psi at WOT."

Eric.
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