engine dies occasionally on deceleration
Lead Driver
Joined: Jun 2004
Posts: 6,340
Likes: 588
From: Amarillo, TEXAS!
IPR duty cycle should be 8-12% at warm idle. Check ICP voltage, key on, engine off. It should be somewhere around 0.2 volts. You may have an ICP sensor that's high-biased.
Hotshot
Joined: Jan 2011
Posts: 18,849
Likes: 179
From: Puget Sound
Yes... this. This is what ICP sensors typically do when they fail - they lie on the high side and make the IPR go low, which robs you of a lot of power. You are in for a rude "awakening" when you fix that - your truck will quite literally kick your ***.
Thread Starter
|
5th Wheeling
Joined: Nov 2015
Posts: 39
Likes: 0
I replaced the ICP about a month ago when this started happening. I noticed that some oil was coming out of the top of it so I knew that it would eventually need to be replaced. I guess I could have gotten a bad one. On monday I checked the system with the key on and the engine off and I got 0.22 volts on the ICP and the IPR was at 14.84%. I will check again KOEO tonight.
Thread Starter
|
5th Wheeling
Joined: Nov 2015
Posts: 39
Likes: 0
I just took the readings. KOEO IPR is 14.84% and the ICP is 0.22 volts. With the engine running - IPR 9.38% which is different than usual, ICP 0.82 volts and 478.7 psi and the fuel pulse width is 2.5ms, rpm is 692.
Does this say anything?
Does this say anything?
Lead Driver
Joined: Jun 2004
Posts: 6,340
Likes: 588
From: Amarillo, TEXAS!
OK, the voltage is good. Now that I think about it, I seem to remember there being more than one PID for IPR duty cycle in ForScan, and they read different from each other. Next time you connect to the PCM, add all the IPR duty cycle PIDs. Make note of which one reads 14.84 with KOEO and use that one from here on out.
Thread Starter
|
5th Wheeling
Joined: Nov 2015
Posts: 39
Likes: 0
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
10 Things Every Truck Owner NEEDS (2026 Edition)
Michael S. Palmer
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Verdad Gallardo
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Top 10 Ford Truck Tragedies
Joe Kucinski
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
It's a Van Gogh
Joined: Feb 2010
Posts: 7,813
Likes: 1,335
From: Elk Grove, CA
RPM looks suspect. 45% ICP DC making 1850psi with 3.94 IPW at... 285 RPM??
What kind of CPS did you install? Possible issue with the related harness. Pretty sure that goes thru the 42 pin, so eyeball the underside of that harness for chafing against the driver side valve cover. Coupla ideas anyway.
What kind of CPS did you install? Possible issue with the related harness. Pretty sure that goes thru the 42 pin, so eyeball the underside of that harness for chafing against the driver side valve cover. Coupla ideas anyway.
Lead Driver
Joined: Jun 2004
Posts: 6,340
Likes: 588
From: Amarillo, TEXAS!
Have you disconnected the ICP sensor and driven it? Try that, if you haven't. If the symptoms go away, replace the ICP sensor. If it stays the same, I'd still lean toward the IPR valve.
Thread Starter
|
5th Wheeling
Joined: Nov 2015
Posts: 39
Likes: 0
RPM looks suspect. 45% ICP DC making 1850psi with 3.94 IPW at... 285 RPM??
What kind of CPS did you install? Possible issue with the related harness. Pretty sure that goes thru the 42 pin, so eyeball the underside of that harness for chafing against the driver side valve cover. Coupla ideas anyway.
What kind of CPS did you install? Possible issue with the related harness. Pretty sure that goes thru the 42 pin, so eyeball the underside of that harness for chafing against the driver side valve cover. Coupla ideas anyway.
I will look into the wire harness and also disconnect the ICP and drive it around to see if anything changes.
Thanks
Thread Starter
|
5th Wheeling
Joined: Nov 2015
Posts: 39
Likes: 0
More info.
I disconnected the ICP and there was no change.
When it dies and I have to restart, most of the time I have to push the fuel pedal to get it started, also sometimes after it has been sitting for a few hours I will have to push on the fuel pedal to get it started.
When I am decelerating and at 50 mph if I shift into neutral and then back to drive the vehicle does not die???
I disconnected the ICP and there was no change.
When it dies and I have to restart, most of the time I have to push the fuel pedal to get it started, also sometimes after it has been sitting for a few hours I will have to push on the fuel pedal to get it started.
When I am decelerating and at 50 mph if I shift into neutral and then back to drive the vehicle does not die???
Elder User
Joined: Sep 2011
Posts: 979
Likes: 4
From: Vancouver
More info.
I disconnected the ICP and there was no change.
When it dies and I have to restart, most of the time I have to push the fuel pedal to get it started, also sometimes after it has been sitting for a few hours I will have to push on the fuel pedal to get it started.
When I am decelerating and at 50 mph if I shift into neutral and then back to drive the vehicle does not die???
I disconnected the ICP and there was no change.
When it dies and I have to restart, most of the time I have to push the fuel pedal to get it started, also sometimes after it has been sitting for a few hours I will have to push on the fuel pedal to get it started.
When I am decelerating and at 50 mph if I shift into neutral and then back to drive the vehicle does not die???
Larry
Senior User
Joined: Oct 2015
Posts: 444
Likes: 0
Originally Posted by exsuv
I am trying to find someone that has a 7.3 that is not in use that I can barrow the IPR to test my vehicle to see if that is the problem.
Also my truck was dying on decel and I ran the **** out of it passing a double trailer tractor and it seems to have cleared her out. I also run Stanadyne in every tank.