NO Start
Thread Starter
|
Senior User
Joined: Aug 2011
Posts: 213
Likes: 0
IPR connector unplugged - Key Off
Red wire > 1000 ohms - use battery negative for meter ground: Measured >2000 ohms
Yellow wire > 1000 ohms - use battery negative for meter ground: Measured 800 ohms
IPR connector unplugged - Key ON
Red wire Battery (12 volts) - use battery negative for meter ground: Measured 12 plus volts
Yellow wire 0 - .25 volts - use battery negative for meter ground: Measured 1.36 volts
These voltage readins were made from the receptacle that the IPR pigtail plugs into, with Key on, IPR pigtail disconnected.
IPR connector plugged in - Key OFF
Measured: 8.3 ohms
Red wire > 1000 ohms - use battery negative for meter ground: Measured >2000 ohms
Yellow wire > 1000 ohms - use battery negative for meter ground: Measured 800 ohms
IPR connector unplugged - Key ON
Red wire Battery (12 volts) - use battery negative for meter ground: Measured 12 plus volts
Yellow wire 0 - .25 volts - use battery negative for meter ground: Measured 1.36 volts
These voltage readins were made from the receptacle that the IPR pigtail plugs into, with Key on, IPR pigtail disconnected.
IPR connector plugged in - Key OFF
Measured: 8.3 ohms
Postmaster
Joined: Sep 2007
Posts: 4,195
Likes: 6
From: Medford Oregon
If it was me I would be checking that Yellow wire really good. Resistance to ground is low and voltage is high. You mentioned earlier IPR wires were soft and spongy, you might replace them .. did you?
Thread Starter
|
Senior User
Joined: Aug 2011
Posts: 213
Likes: 0
Okay, thanks.
I disconnected the 42 pin harness right under the fuse box and I have corrosion on lots of pins. Not a ton, but you can see it.
I ohmed the red wire and the yellow wire from the female plug and both wires showed an ohm or two, that is if I am checking the right pins. I don't have a diagram for I just went from pin to pin till I found two with continuity and it was a couple of ohms.
I am going to the auto parts store to get some pin cleaner, maybe that is part of the problem.
I disconnected the 42 pin harness right under the fuse box and I have corrosion on lots of pins. Not a ton, but you can see it.
I ohmed the red wire and the yellow wire from the female plug and both wires showed an ohm or two, that is if I am checking the right pins. I don't have a diagram for I just went from pin to pin till I found two with continuity and it was a couple of ohms.
I am going to the auto parts store to get some pin cleaner, maybe that is part of the problem.
Thread Starter
|
Senior User
Joined: Aug 2011
Posts: 213
Likes: 0
Okay, I cleaned all the pins on the 42 pin connector and when I coupled the connector back to the receptacle, I checked ohms on the yellow wire again. It is still 800 or so. But from the female pigtail to the IPR connector it is only a couple of ohms. So, it must be a problem between the connector and the PCM?
Thread Starter
|
Senior User
Joined: Aug 2011
Posts: 213
Likes: 0
I found the yellow/red wire coming off the PCM connector. I disconnected the PCM female connector and ohmed from there to the male connector just below the fuse box. I am assuming this takes into account everything through the fuse box. I got 2 ohms. I don't get it.
Postmaster
Joined: Sep 2007
Posts: 4,195
Likes: 6
From: Medford Oregon
I really think from you post above you need to look at the IPR wiring harness from the IPR connection to that 5 pin connector where you re-connected (hard wired) the two wires. Disconnect the yellow wire and take a resistance measurement as described above, key Off, the one going to the engine harness and see what the resistance is, and voltage with key On.
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
Top 10 Fords at 2026 Carlisle Ford Nationals
Joe Kucinski
3 Best / 3 Worst Parts of Modern Ford Ownership
Brett Foote
10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches
Pouria Savadkouei
Every 2026 Ford Engine Explained
Brett Foote
10 Ugly Ford Trucks That We Still Kinda Love
Joe Kucinski
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
Thread Starter
|
Senior User
Joined: Aug 2011
Posts: 213
Likes: 0
I got rid of my hard wiring and put a harness back on.
Red wire(after glow plug relay shuts off,key on) has 12.3 volts.
Yellow wire now has 0.8 volts.
When I check continuity between the red and yellow wire at the harnes plug ( not IPR pigtail), I get 2 ohms, showing no problem with the wiring from IPR to the 5 prong (now on 2 wires though) plug.
Truck still won't start. It took a lot of cranking to show oil pressure on the gauge though. HPOP might have been a little low.
BTW, than you for your help. I have been fighting this for awhile. It is now a vendetta. My wife tells me to just have it towed to the shop.
Red wire(after glow plug relay shuts off,key on) has 12.3 volts.
Yellow wire now has 0.8 volts.
When I check continuity between the red and yellow wire at the harnes plug ( not IPR pigtail), I get 2 ohms, showing no problem with the wiring from IPR to the 5 prong (now on 2 wires though) plug.
Truck still won't start. It took a lot of cranking to show oil pressure on the gauge though. HPOP might have been a little low.
BTW, than you for your help. I have been fighting this for awhile. It is now a vendetta. My wife tells me to just have it towed to the shop.
Hotshot
Joined: Aug 2006
Posts: 10,764
Likes: 39
If it doesn't see 500psi ICP it will not tell the IDM to fire the injector's
THe PCM sends ground to the IPR in a pulse that cannot be measured with a meter
Only after the ICP sensor sees what is need to start,The PCM will tell the IDM to fire the injectors
You need to either find someone that can read the codes , or change the PCM to a n OBD II that can. You have a code stored that can narrow the problem ..
This is the most hard to follow thread I have ever read .. Questions are asked & no answers are offered .. We can fix this if you are willing to help by answering the questions posted.. You have been all over this motor with no results
Thread Starter
|
Senior User
Joined: Aug 2011
Posts: 213
Likes: 0
If I have the red wire for the IPR going into the right side of the IPR plug, is that correct?
I think I have answered most questions the best I can, but it just seems, like nothing is making sense. One day my HPOP is full, the next day it isn't. One day my tach moves and a day or two it didn't. A few days ago, I was driving the truck and it would start hot, no problem. Now it won't start at all.
Guess I need to figure out a scanner I can buy or rent one, and get the codes.
I think I have answered most questions the best I can, but it just seems, like nothing is making sense. One day my HPOP is full, the next day it isn't. One day my tach moves and a day or two it didn't. A few days ago, I was driving the truck and it would start hot, no problem. Now it won't start at all.
Guess I need to figure out a scanner I can buy or rent one, and get the codes.
FOREIGN GURU
Joined: Jul 2006
Posts: 7,655
Likes: 7
From: Celaya, Gto. MX
Dear friend with all the respect I suggest you to start a new thread with your questions, because this thread is way to convoluted already, OK?
