I reached out to Sous on this and he suggested I asked everyone, So here we go, I kind of wrote a book.

I have a 03 with 137K all stock except intake and Mishimoto 60 trans cooler. Since I have had it I changed all fluids the first year along with regular oil changes. I pull a 31' Open Range 5th wheel and it has never missed a beat while driving.
In November 2021, I drove to San Diego and picked up my son at the airport, about 125 miles round trip, for Thanksgiving. Parked it that night and the next morning it would crank as normal and not start, no smoke at the pipe or anything. I had read I should keep an OEM Cam Sensor in the glove box, so I replaced it and still nothing. I had it towed to a local Diesel Shop. and when it arrived on the roll back, it started. They said it had no codes. I asked for a full diagnostic check, and nothing was found.

It has happened a total of 5 times, 11-21, 10-22, 2-23, 5-23, and in 7-23. Each time driven and parked the night before and the no start is in the morning. It has never stumbled lost power or any such problem while driving.
Twice in my driveway, the first three times, when it got to a shop it started.

The 2nd time was in October, we left home about 9 PM with the 5th wheel and drove up and over the Grapevine, parked for the night north of Bakersfield. nice cool evening drive, pulled the hill fine, never a stumble or problem. The next morning, no start. Searched online and found a 7.3 shop in Bakersfield that could get me in. When we got there, it started up, again said there were no codes. The shop owner said he has had aftermarket alarms causing no start issues. I said fine, take out the Viper alarm. And since he was under the dash, I asked him to remove the Electronic brain to check the connection for corrosion, All were clean.

Feb was in my driveway and again started at local the shop.

In May, we were at a semi local RV resort. This time when it got to the shop, it would not start. Shop called and said they pulled the CPS wiring and it started, so it is a bad wiring harness. I was not convinced, first off, I changed out CPS and no doubt jiggled the wiring the first time. and mainly I have hit bumps, driven bumpy paved and unpaved roads and have never had a stumble or has it died. Also, I was told they were having trouble locating a top of engine wiring harness....
I really wanted to be able to wiggle the harness and as some sort of a confirmation.

July at a rest stop off the 5 in Oceanside. I wiggled the CPS and other wiring four ways to Sunday.. Nothing As I was riding in the tow truck, I had the driver stop 5 times to see IF it was going to start. back to the shop, they are now saying it has low oil pressure.
IN my mind that is something that is NOT intermittent at all.
I am beginning to think the local shop, is in over their heads and I do not want to get into the parts changing game.

There is my story, Do you have any suggestions or thoughts.

Thank You,
Ron

Sous replied:
Ron, I will do my best to address your questions, but I would encourage you to start a thread on the public forum in an effort to gain several perspectives on your questions. Usually... More minds involved is better than one or two, usually...

The cam sensor (CPS) is capable of going bad, but I feel it gets a lot of blame for other parts that are failing. I too carry a CPS in my truck for the just in case moments.

You mention it was a diesel shop that serviced your truck. Most scan tools will not read the PCM codes, but let us assume that they were able to. No codes does not surprise me because you didn't mention that there was a check engine light or some abnormal running condition. CORRECT, Never a check engine lights & nothing abnormal.
There are some soft codes that can be set that will not illuminate the check engine light, but 99% of those will not stop the truck from running.

I have some questions...
Is your driveway slanted toward the rear of the vehicle by chance? Yes, it has a slight angle, although this has happened three times on flat level ground.
What is the oil and fuel level when the truck would not start? Always high 3/4 or above.
Have you done the Hutch/Harpoon mods by chance? No, its n the list but not yet.
Did you hear the fuel pump priming the system when the ignition was turned to ON? Yes, the fuel pump sounds as per normal
Have you unplugged the ICP sensor on the driver head and tried to start it? I unplugged the connection, to see if it was oily, it was not but I did not try and start it unplugged.
Check the oil level in the HPOP reservoir, it should be about 1" from the top. NO, I have never checked the level when it would not start.
Are the connectors for the PCM and IDM tight and secure? Yes, I have removed and replugged them
Do all of the lights and everything appear to work properly when the engine will not start? Yes, as far I I have noticed, all lights electrical work same as normal

The not starting in your driveway and then starting at the shop makes me think it is a loose connector or a fluid level, but that is just a hunch. AGREED, and after the it started when taken off the truck, I have jiggled and pulled about all exposed wiring in the engine bay
Low oil pressure could be a thing due to the HPOP reservoir draining back overnight. Although, once the LPOP fills the HPOP reservoir during the day, there would be no abnormal running conditions.

Fuel pressure and fuel related problems will NOT throw a check engine light or store codes, just FYI.

Get back to me with a few more details and address the questions and we will see where we arrive. I sincerely hope we are able to resolve this for you. Shops are just parts chuckers for the most part anymore and I am sorry you are getting the runaround.

 

Subscribing. And this is just a wild hair guess, but I wouldn't be surprised if some ground wire or other positive electrical connection may be loose and/or corroded enough to cause the no-start. Then load it up on the tow truck and all the josteling while under way jiggles the culprit connection enough to bring it "back to life" so to speak and then it starts. Not a real likely scenario, IMO because of the absence of codes stored, but maybe it's the PCM relay not turning on?
Again, I'm just guessing here.

 

Agreed, I have spoken to an Auto electric shop and was told bring it in. WIth all the spaghetti bundles of wiring, I am out of my depth.

I will be sure to post "When" I am up and running.

Thanks

Ron

 

Ron, I am grateful you posted in the public forum. I consider myself a pretty good shade tree mechanic and have learned a lot about the 7.3L PSD, but there are fellas on here that have forgotten more than I will ever learn.

A couple of other things that popped into my mind as I was mentally rereading your PM are below.

• You could get FORScan or FORScan Lite set up for a small amount of cash ($5 - $25 in most cases) and provide us with PID readings as the truck is cranking and not starting. This would give us a clear direction to point you in. Check out this thread for easy directions on how to set up FORScan or FORScan Lite.

Link: FORScan + FORScan Lite: Class Tutorial Q&A

• Have you checked the bundle of wires that rests over the driver side valve cover that is coming out of the 42 pin connector? This is a known chaffing spot as the bundle sags and rubs on the valve cover. Below is an image I borrwored from Google Images.

• The next time the truck fails to start, remove the plug on top of the HPOP reservoir and check the oil level with a bright light. It should be about 1" from the plug hole.
• When turning the ignition to ON from OFF, the "Wait To Start" or glow plug light comes on right?

If it is an electrical/connector issue, there are only a few things it could be that would stop the truck from starting at all. Keep us updated and come back to us with more answers and/or questions.

 

sounds like a relay with worn or corroded contacts

with key on, punch/smack the relay/fuse box near the turbo next time and see if it starts

 

Ron has a 2003 and I "think" that the 2003 did NOT have the fuse/relay box under the hood. I believe that all of the fuses and relays are under the dash in the 2003, but I could be wrong as I have a 2000 and usually focus my attention on that MY.

 

Some good ideas here.

I got lost a little. Is it unable to start currently or is it running again? It’s awful to say but consistently not starting would be a big help while trying to diagnose this.

My first thought is that you need a way to see what the PCM sees when it’s not starting. Sous mentioned FORScan. I would get that and check that out next time it doesn’t start.
There are some required items before the PCM will say “fire up.” I don’t always remember them all but the others can fill them in.
ICP: greater than 500 I believe
RPM:
voltage:
sorry I don’t remember the details.

The electrical ground/connection theory sounds valid.

I’d also want to check fuel pressure during a no start. Have the tools ready to go (or install a gauge to have forever).

I would do like Sous mentioned and check HPOP reservoir next time it doesn’t start. Then I’d disconnect the ICP and try as well.

Good luck!

 

Tough one since it happens very intermittently and does crank when it happens. HPOP reservoir, ehh. Seems unlikely a ride on a flatbed to the shop would magically make the reservoir fill itself again. I've ran mine empty from not pre-filling the oil filter and the motor just shuts itself off, but a couple longer cranks on the starter and it re-primes itself.

Occasionally something is failing to initialize which could be a relay sticking. PCM relay perhaps. Ignition switch on the underside of the steering column sometimes acts up, but I think that usually causes a no-crank.

 

Truck is current is no start, sitting at American Diesel. I was promised today, they will get to it, AS stated earlier, I was now told low HPOP pressure, so thats the test being done, today? Seems weird to me, an intermittent issue like mine, and has never had a lack of power, and "after the episode ran fine till, another random morning no start.

Glow plug light comes on normally and has never been below I guess mid 50s when it has not started. Not so frigid SoCal weather

I checked my truck folder notes and found :er 22, when it did it in Bakersfield, October 2022, "Limitless Industries invoice" shows:
PO460 Fuel Level Circuit (gauge is non op, I have been very sucessful in monitoring gallons and mileage, plus have a 3 gl tank in the bed, gravity flow),
P1248 Turbo Boost un- detected.
PO 0600 Serial Port Coms Link Error
In February 2023, I checked the HPOP Reservoir and wrote down the level was within 1/2" from top, that time I also disconnected the batteries for 1/2 hr to see if a Reboot would do anything. nope

I have Torque Pro but if Forescan is the way to go, I will definitely upgrade. I went through a couple Bluetooth units but the current one seems to be the best.

I have unplugged, wiggled and looked at the 42 pin connector on drivers side, but I now say, foolishly didnt try and rotate it to see the bottom valve cover side of wires... I see where that could be a rub point. The passenger side has those clips that almost look like 3/4" hose clamps that also have fairly sharp plastic edges. I looked and didnt see any chafing there where I could see anyway. THIs last time when we were stuck a the restarea, I unplugged wiggled and shii=mmed about all with, but again and maybe foolishly didnt try and start with ICP disconnected.

This random issues has become consistent, because as we all know, things just DONT fix themselves.


Ron

 

A truck with that mileage would be surprising to find the pump itself no good. However the ICP sensor and IPR valve are known to cause issues, but are not difficult fixes. As others have mentioned already, the ICP sensor can be troublehot by simply unplugging it.

ForScan and a laptop USB adapter is a nice tool to have around. I also really enjoy having a CTS Insight for quick and easy sensor data without needing to break out the laptop and cord, but it won't do everything ForScan will.

 

Subscribing

 

 

Ron, I certainly would not have been leaning toward a failed HPOP and would not have expected "0 PSI" when dead heading the HPOP. Especially when the poor running condition is intermittent. The shop is right on at least one account, they accurately described how things break.

I don't want to say the shop is wrong because I am not there and am unable to see the test procedure they utilized and the results.

The next step is up to you Ron, but if I were in your situation I would get FORScan or FORScan Lite (FSL) setup and see what the PID's are indicating when you have a no start condition. There is a 90% chance we can help you pinpoint the issue with some data from FORScan or FORScan Lite. Torque Pro (TP) can be helpful, when it wants to be. TP is good at working when it feels like it and looking pretty. Other than that, FSL is the go to for rock solid data when you need it.

Finding good help is difficult in the age of throwing parts at a vehicle, but at $500+ dollars for a HPOP this can get expensive quickly.

I am not sure where @duck fan is located in relation to you in CA, but he may be able to offer some good advice.

Lastly, if you decide to bring the truck home and see what the PCM is telling you during a no start condition, have a look at this "no start flow chart". It is usually able to point out where the problem is.

Link: No Start Flow Chart - FTE Created

 

Ron, I was thinking about this a bit further today while working on other projects. Since you have TP and you are somewhat familiar with it, would it be possible for you to go to the shop and bring TP up while you are attempting to start the truck? The shop may still have the HPOP in "dead head" test mode though and I don't know if you want to seem like you are questioning their diagnosis.

If the truck is back in the lot and outside, you could take a few minutes and go through the no start flow chart with TP running and see what you see. We would want to see the PID's below in a data log or a screen record while cranking the truck.

RPM(1/min) – Engine revolutions per minute

IPR% - IPR duty cycle percentage

ICP(psi) – Injector Control Pressure (select ICP, not ICPV, as seen in the image below)

FUELPW(ms) – Fuel injector pulse width

VPWR(V) – Vehicle battery power

Again, I cannot say for sure the shop is wrong, but my gut is telling me the problem is not the HPOP. I have been wrong many times before though and was a couple of times today alone...

 

@Sous thanks for thinking of me. I'm in the best and worst location for most of the state. Right about halfway up the coast.

I would be suspicious of an HPOP that produces zero pressure. Even a dead pump should have 50-65psi of flow through from the low pressure side.

The challenge is that most shops, even diesel shops, do not have a good grasp, or even no grasp of the HEUI system so their solution is to throw a pump at it. We need more information to point you in a solid direction.