Hello everyone. I've got a 2002 7.3 F250. It's only got about 125K miles on it. I bought it from my dad a few years ago as he just didn't drive it much. It runs great.

In the last 2 months, I have had about 6 Crank/no start issues when the truck is at operating temp. When cold, it starts great. Maybe a little smoke when it's below freezing. When running, it runs great. These Crank/no starts have happened when I stop the truck and then try to start it within a few minutes of stopping (gas fill up, adjust bad parking, etc.) It will Crank fast but just wont fire. If I let it sit 5-20 minutes, It fires right up like there was never a problem. One time it was after the truck had been sitting for about an hour but every other time it has been during a quick restart.

It was time for an oil change, so I had my regular shop check it out. One of my air temp sensors was faulting. They cleaned the connection, got it reading and told me it may have been my problem. All was well for about 100 miles, then I had another Crank/no start. I did my research and got an OBD reader and Forscan. I have very little motor knowledge/ability, but I figured that being an intermittent issue I needed to get some data before throwing money at it. I will have a shop do the work but I'm hoping to narrow it down for them. Please let me know if I'm on the right track.

When Starting/Running right

IPR % peaks to about 34% on startup then idles around 9.5
ICP PSI peaks at about 1000, then idles at about 500
ICP Volts builds to about 1.7, starts, then idles about .8
Battery Volts dips down to about 11v on startup

Drove for about 30 minutes. Shut it off, it started right up. Drove another 10 minutes. Restarted very long/hard start.
Hard start data

IPR % Peaked at about 62%
ICP PSI Peaked at 3000
ICP Volts Peaked at 3.6 V
Battery dropped to about 10.8

I shut it off again and did an immediate restart. This time Crank/no start several times.
Crank/no start data

IPR % Peaked at about 64%
ICP PSI Peaked at 156
ICP Volts Peaked at .43 v yes point 43
Battery dropped 10.75
RPM hit 202 each attempt.

This data seems very strange. Again, I am not a mechanic, I just scour the internet and try to learn and hopefully save money. I'm hoping it is obvious to someone on here. I am thinking that the Injector pressure regulator is getting stuck open. The 156psi would not be enough to start the engine. But why did it go so high on the hard start? Maybe it got stuck closed too? This was the first time it actually had a hard start. It usually starts right up, or just cranks with no attempt to start. Please let me know what you think or if you need any more data or if I need to run more tests. One other thing is that the truck does have a very minor oil leak somewhere in the back and down the bell housing. Seems to only be when the engine is running. It leaves 1-2 tiny drips in my driveway a week. Unnoticeable on the dipstick on an oil change.

I'm going to keep collecting starting data. Is it ok to leave the OBD plugged in? Will it drain the battery?
Thank you for your time.

 

Sounds like the solenoid that controls the IPR valve is getting weak. Could also just be the tin nut that holds said solenoid in place has gotten lose or even come off. You can reach down in the valley at the back of the hpop and check the nut is snug. It only needs to be 1/4 turn past hand tight. It is just a tin nut after all. If that checks out then you've got 2 options. First would be to remove the solenoid and check resistance across it's terminals. It should read around 10.5 ohms. Another test is to keep cold water in the truck and next time it gives you trouble try pouring the water over the solenoid to cool it down. If you get it cooled off and the truck starts that's pretty much a nail in the coffin for the solenoid. The trouble there is you have to buy a complete replacement valve to get a new solenoid. They run around $240 now days, so it stings a little. Only use Motorcraft parts from a reputable vendor for all engine management sensors. The internet is over run with fakes and knockoffs. If you're not paying north of 2 bills for it you can bet it isn't genuine.

 

I had intermittent crank/no start, after truck sat for about 30-45 it would fire again and act like nothing was ever the matter. Ended up being IPR.

Re-reading my old thread sounds identical to your issue.
https://www.ford-trucks.com/forums/1...-ipr-help.html

That was about 8 yrs and 5-7k miles ago(no longer my daily) and just replaced that IPR with new Motorcraft part from Rif Raff. Seriously when it comes to any sensors on these engines stay with Ford.

 

Thanks for the advice. I made an appointment for next week to have the IPR checked out. Looking online, "genuine" Motorcraft IPRs are selling for $100 to $600 which seems absurd. I assume the $100 ones are fake from sketchy websites. The $400-$600 ones seem like legit sites but crazy prices. I'll talk to the shop and make sure they use motor craft parts and I better ask the price upfront.

I checked out the IPR myself tonight to see if the nut was loose. I found that a pack rat had made a nest underneath all the wires in the valley. I spent 30 minutes vacuuming it out the best I could. There were dog toys in there, sticks, shop rags, etc. What a mess. I checked all the wiring I could see and didn't see any that had been chewed up. I pushed on all of the connections and tightened the tin nut a little. It didn't seem loose.

I drove the truck about 45 minutes, stopping and restarting occasionally. Ran great and I wasn't able to get the Crank/no start. Being intermittent, I doubt I fixed anything but maybe there was a loose wire that I secured. EOT seemed to be running about 5 degrees cooler. Maybe just a cooler evening.

I'll update this post as I go through the process.

 

Might be 5 degrees cooler simply from removing the rat feces insulation that was packed in the valley. Here's a link to Riff Raff diesel they are a trusted source for parts. If they say it's Motorcraft then it's Motorcraft. I don't know who's trying to sell them for $400 and $600 but that's just insane. It was real money right? Not that stuff with dead people you've never heard of's picture on there right? Sadly those are probably fake as well

https://www.riffraffdiesel.com/ipr-i...gulator-96-03/

 

https://www.riffraffdiesel.com/ipr-i...gulator-96-03/


I noted they have two versions available, what is the "Edge Filter" mentioned for the 2nd version?
they do NOT give a full description of the part.

 

I would stick with the Ford dealer or Riff Raff, just who I have personally used, for parts. When you go down the eBay rabbit hole I am leery. Basically I could take the packaging I got from Riff Raff and re-package a cheaper IRP, hell could probably clean up the old one I took out, and pawn it off as a "genuine" part. But I am also very untrusting of the general public and the interwebs, at least when there is a profit to be had.

Additionally it is difficult to go more then 10-20m talking about a issue without RiffRaff coming up as a reputable supplier, and I 1000% recommend them. My IPR that was delivered in FEB was $238(270 w/ shipping and the tax mans cut). I believe Ford was in the same ball park, but honestly I wanted to give RiffRaff some business to test the waters, I have turbo rebuild and other fun stuff in the pipeline. So far, part perfect and excellent service around my turbo questions, responsive and helpful.

Sounds like your on your way, good luck and hope everything goes smoothly.

 

It is all by year, only the 1994-1995 used the edge filter IPR.

Just grab one from Riffraff Diesel and you know you will have a real one and their pricing is better than the Ford dealer. I just ordered a couple for my shelf last week and noticed they have the very newest version from Motorcraft of the IPR. My dealer doesn't even have this newest version yet. I kinda wonder if Motorcraft changed the packaging and appearance of the IPR due to all the counterfeit on Amazon and eBay.

https://www.riffraffdiesel.com/ipr-i...gulator-96-03/

 

One of the critical components for engine operation is the camshaft position sensor. It's construction is a Hall effect sensor.
Google: "Hall-effect sensors are integrated circuits that transduce magnetic fields to electrical signals with accuracy, consistency, and reliability."
Typically the way that they fail is they function normally when they are cold, then lose signal as the engine warms up. The way your truck is failing could very possibly be that the cam sensor is getting hotter than it usually does during normal engine operation because you drove it somewhere, then shut it off, then the engine goes into what is called "Heat Soak" where underhood temperatures go way up before the engine starts to cool back down. Hence the reason for being able to get it going again after waiting for a period of time.
Cam sensors are not that expensive and they have a track record of less than rock solid reliable service. I've replaced many a Hall sender in my day in gas engine distributors, etc, and the cam sensor is no different for these Powerstrokes.
https://www.riffraffdiesel.com/cam-p...sor-cps-94-03/

 

When I was first researching my issue, it sounded like the CPS but after getting the OBD and forscan, I can see that my RPMs are adequate for starting. I might be wrong, but I thought RPMs wouldn't register if the CPS was faulty. At this point, IPR sounds more likely. I drove the truck all day today and frequently restarted it when hot. It has been perfect ever since cleaning out the rat nest, pressing on all wire connections, and slightly tightening the tin nut. I doubt that really solved my issue but I keep getting surprised when it fires right up after parking. Intermittent issues are frustrating that way.

 

If there is no signal from the cam sensor a code will be stored right away. Since you scanned it and no code present, it seems you are on the right track for a complete repair. 20 year old electrical connections can be very temperamental and I think that issues springing from that arena are going to start popping up on these trucks across the board as time goes on.
If it were possible to buy an old school mechanical diesel engine vehicle brand new I would be first in line to purchase one.

 

the CPS sits about 1/1000ths of an inch from the cam gear.
if some debris gets in the oil, and slides in between the CPS and the cam gear, that CPS is slated for failure.

IF, you put an Oscilloscope on the CPS, and monitor the output Waveform, you can see that it will miss a pulse once in a while, it could be that the cam gear has a divet in the gear, and the same pulse cycle is missed on every revolution.

in any event, the CPS will go bad by degrees, usually not all at once, but it can happen.

the connector must be clean of oil/moisture because the signal from the CPS is extremely weak.
any shunt to ground will cause bad signals from it.

Hall Effect sensors are extremely good, and normally very reliable.
but they are not immune to damage from debris and oil soak.

the old saying, " keep the Oil Clean " is just as true for the CPS, as it is for the IPR...
an IPR that always has clean, fresh oil, can run over 100,000 miles,
but let that oil go way past change time, and it carbons up.

 

After driving for a while, the crank/no start happened again. I had the IPR replaced. Just went on a 1500 mile road trip and it ran like a champ and started every time.