Throttle issue
Got Data?
Joined: Dec 2012
Posts: 4,236
Likes: 1,368
From: Lake Stevens, WA
Indiana! Ok then.
Absolutely, you can run the ICP sensor unplugged for days at the full range of engine performance, and it's a good thing to try, to help isolate an ICP issue between ICP sensor/wiring and IPR valve/wiring. I had to do this when my ICP sensor leaked oil in the connector and caused a stall. Unplugged the ICP sensor and continued towing a travel trailer over a steep pass and on to a campground. Then back home, about 240 miles total, and it did very well, though I had some loping cold starts - no big deal.
Now if your IPR valve and/or associated wiring is bad/intermittent, and that's our theory here, unplugging the ICP sensor will not change the behavior you are seeing. It will not run well in the scenarios you showed us, but it will confirm what to focus on for the fix (I hope).
Absolutely, you can run the ICP sensor unplugged for days at the full range of engine performance, and it's a good thing to try, to help isolate an ICP issue between ICP sensor/wiring and IPR valve/wiring. I had to do this when my ICP sensor leaked oil in the connector and caused a stall. Unplugged the ICP sensor and continued towing a travel trailer over a steep pass and on to a campground. Then back home, about 240 miles total, and it did very well, though I had some loping cold starts - no big deal.
Now if your IPR valve and/or associated wiring is bad/intermittent, and that's our theory here, unplugging the ICP sensor will not change the behavior you are seeing. It will not run well in the scenarios you showed us, but it will confirm what to focus on for the fix (I hope).
Lead Driver
Joined: Oct 2005
Posts: 6,129
Likes: 1,919
From: Ponca City, OK
The fact we have the data to review suggests the PCM is receiving all the info as well, so either it's seeing something we haven't yet causing it to go in to protection mode or the signals it's send out for more ICP aren't getting where they should or the mechanical components can't keep up with demand. What about a high pressure leak in the hpo system? It holds well enough at lower ICP but peg the needle and the flood gates open. Maybe the hpop internal relief valve is opening up and dumping pressure.
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More Turbo
Joined: Apr 2012
Posts: 628
Likes: 10
From: Florence
Okay I unplugged the ICP sensor and the truck is completely asymptomatic it pools and drives like exactly it's supposed to do it's not smokey anything like that I had a little bit of smokey on idle at startup before and now it's gone it did throw a check engine light though but I don't have my scanner with me so I will get back with what that code is what does this mean?
It's like a completely different truck... So much better power!
It's like a completely different truck... So much better power!
Got Data?
Joined: Dec 2012
Posts: 4,236
Likes: 1,368
From: Lake Stevens, WA
It means keep driving it for a few days and make sure it's running well. ICP disconnected will throw a SES light and code. This is good news, and different from what I expected (also good - I love surprises, it's how we learn). Your IPR is responding correctly to PCM commands it seems. So you might have an ICP wiring issue, or faulty ICP sensor.
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More Turbo
Joined: Apr 2012
Posts: 628
Likes: 10
From: Florence
After several days of driving of all types including towing a vehicle the truck is still running perfect with the ICP sensor unplugged, I inspected the wiring all the way back to the bulk connector and inspected the bulk connector and everything is intact with good continuity across the bulk connector. Contacting RiffRaff for a return on the sensor. Will update with results after faulty sensor replaced.
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More Turbo
Joined: Apr 2012
Posts: 628
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From: Florence
I decided to go with a dieselsite icp sensor... It has a 12 month unlimited mileage warranty... I've driven the truck a good amount and it is perfect now! Thanks to everyone for your help with this problem!
Rick
Rick
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More Turbo
Joined: Apr 2012
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From: Florence
Whelp, the problem still is occuring although less frequently, i installed a HPOP gauge and now can see that when the issue is occurring there is very low oil pressure being seen. The issue is only occurring during decelleration while going down a hill above 70 mph. once i let the truck slow down the pressure recovers and the truck drives normally... Do i assume that i have a dying HPOP at this point? the system is showing being overfilled on the dipstick but it does seem to be occurring less since i added more oil to the system. I really dont want to buy another HPOP if i dont have to but it seems like this is probably the problem? anyone have any other ideas? Thanks for your time and consideration!
Rick
Rick
It's a Van Gogh
Joined: Feb 2010
Posts: 7,795
Likes: 1,326
From: Elk Grove, CA
When you replaced the ICP sensor did you inspect the wring connector? If wet with oil a good shot of spray contact cleaner will get the oil out.
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From: Henderson, NV
@truck7575 The HP oil pressure dropping too low when decelerating is odd. How is your ICP gauge hooked up? How low is low? Does it drop below 500psi?
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More Turbo
Joined: Apr 2012
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From: Florence
@truck7575 The HP oil pressure dropping too low when decelerating is odd. How is your ICP gauge hooked up? How low is low? Does it drop below 500psi?
Thanks
Rick
Last edited by truck7575; Oct 29, 2025 at 10:21 AM.
Got Data?
Joined: Dec 2012
Posts: 4,236
Likes: 1,368
From: Lake Stevens, WA
When you unplug the ICP sensor, do you get your performance back? I thought you had several days of good results with the ICP unplugged.
Is your HPOP gauge a mechanical gauge, or running through a sensor?
With the ICP sensor unplugged, how does your HPOP gauge read? Steady or bouncing?
Is your HPOP gauge a mechanical gauge, or running through a sensor?
With the ICP sensor unplugged, how does your HPOP gauge read? Steady or bouncing?
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