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Discussion Starter #1
1995 7.3 diesel. Today it was difficult to start in the AM. In the afternoon it starting stuttering and stalling. It would start right up after and drive for a while and then do it again. I got it home and changed the CPS and it wouldn't start at all. Changed the fuel filter and still no luck. It just cranks and cranks. I few times it sounded like it would turn over but no luck.
Any thoughts?

Thanks,

Eric
 

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Basics first! Any mods to the truck like a chip or tuner? Check oil levels in pan and HPOP reservoir before starting. CEL illuminated? Wait-To-Start coming on as normal? Any white smoke out the tailpipe when trying to start? Tach showing any movement when trying to start? What's the fuel pressure when cranking (measured at the schrader valve on the driver's side of the fuel bowl)? What are fuel levels in tanks (try switching tanks)? Cheers!
 

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Eric,

First off - Welcome to PSN. I'll second what Patrick said and add.... As it is a 95 this next bit may be hit or miss as the OBD port may not yet be activated on your truck. If it is activated you will save your self a lot of headaches (I would take it in and get the port activated after you get back on the road). Download FORScan and buy an OBDlink EX or a BAFX dongle (you can read about them on FORScan.org). Then go and select ICP, IPR, RPM, MAP, BARO and EOT for monitoring.
As Patrick said - Does the tach gauge move at all during cranking? If yes then you can also try unplugging the ICP. With the ICP unplugged the truck will default to PCM based lookup table for the ICP pressures.

Cj
 

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Discussion Starter #4
Thanks for the welcome and response. The previous owner did install a lager Banks Turbo with a chip. (I've only owned this about 2 months now). Both tanks are full. I have tried switching tanks. No white smoke. No CEL. Wait to Start light does come on as usual.

I can check the fuel pressure at the Schrader Valve, but since it will only cranking, should I still be seeing 40 to 70 when cranking or if lower is that acceptable?

I'll try disconnecting the ICP and let you know what happens.

I do have an Auto X Ray scanner with several cables. I'm a gas guy, this is my first diesel. That unit does OBD I and II. Will that even work for a diesel or do I need a different scanner or different software / programming for the scanner? The check engine light is not on so I'm guessing (like on a gas rig) there will be no error code to read? The previous owner did say years ago he took it into Ford and they plugged it into their "Big Scanner", as he put it and determined the CPS was defective. Would that indicate the port has been activated?

I'll jump on this now and post up how it's going.


Thanks,

Eric M.
 

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Eric,

Does the truck have larger injectors? If not I would remove the chip for testing.

97 and older trucks use a cam driven fuel pump which should develop full pressure even cranking.

Your scanner may or may not work... As I understand it the 7.3 diesels use a "heavy duty" diesel protocol that is not readable by ordinary scanners (though I have heard that the PIDs might be). It seems like there isn't much that turns the CEL on in these trucks. Sounds like your port may be active - only way to find out for sure is to try it.

Cj
 

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As cjfisher mentioned, definitely remove the chip and see what happens. Many times the contacts get to where they are not making good contact. Don't have they key anywhere near the ignition! Cheers!
 

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Discussion Starter #8
OK, here's an update:

HPOP - topped off, it was a little low. No start.
Tach - yes it does move when cranking
-Fuel Pressure at Schrader Valve - 40 plus pounds after a few cranks
-Disconnected IPC - No start.
 

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Discussion Starter #9
Forgot to mention, the CEL light did go on while cranking when the ICP was disconnected.
 

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CEL will go on for ICP issues.
The 7.3 is pretty simple - you need 150+ rpm crank speed and oil pressure for the PCM to start firing the IDM. CPS is covered as the tach is moving, ICP which will lookup, which leaves you with an IPR or HPOP to check.
 

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Discussion Starter #11
I just removed the Banks chip. The contacts on the computer were dirty so I cleaned. Tried starting gain with and with out the chip. No luck.
Any advice on how to test the HPOP and the IPR? I have 3 factor manuals ans non address any of the things I'm checking. I'm think there was a 4th I didn't get.

-1995 Powertrain, Drivetrain
-1995 Body and Chassis
-1995 7.3 Direct Inj. Diesel Supplement (You'd think this would be the go to book, but not really)
Is there another I'm missing?

Pointers for HPOP and IPR testing or should I just search YouTube?

(Thanks for all the help, I really appreciate it. My truck is stuck on my front lawn. We were in the middle of stripping our roof to redo when this happened. It's not the prettiest lawn ornament!)
 

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At this point you need to break out your code reader and see if it can read RPM, IPR and ICP values. Or get some mechanical gauges and hook them up to the high pressure oil system - just make sure they are rated for 3000+ psi (5000 psi would be good). Search the forums for how to dead head the HPOP.
 

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Also... just for kicks.. check all the UVCH connections for burned, melted pins.
 

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Discussion Starter #14
UVCH connections all look good. I'll look into HPOP and IRP testing. I read that if one is bad, you need to replace both. If that is the case, which should I start with? I don't have any gauges that go to 5K PSI.
 

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Discussion Starter #15
Hmmm, as I read about HPOP testing here on this site, I think I need to mention something. There has been an oil spot in my driveway since I got the truck. Never thought to look into it as all my gas rigs leak and that's just how it is. Is this a tell tale sign of anything? Should I trace the leak to see where it's coming from?
 

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Discussion Starter #16
Well, as I search this forum looking for solutions, I'm finding many that have spent thousands on parts and put many hours doing everything from removing gas tanks, replacing harnesses, testing, removing, cleaning, etc. and still ended up taking to a shop. I'm thinking I might cut my losses and do that. I was hoping it might be something simple but the further I get into this, I'm thinking it could be a bigger issue.

I'll post up what it was for others doing searches in the future.

Thanks again for the help.
 

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You can nickle and dime yourself broke by just replacing parts on these engines and not accomplish very much.

Also one you replace a couple of the more inexpensive and common items that go bad you need a scanner that can read the live data to figure out which way to go....Sometimes a shop is the cheapest way to go if they can do the diagnostics and repairs properly.
 

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Discussion Starter #18
Yeah, I hear you. I've never had any of my gas trucks in to a shop, I've always been able to do the work myself. But then I've been tinkering with gas since I was a kid. My scanner tool won't work for this truck, so, right there is a big investment. I need to swallow my pride, pull out the check book and just do it. I've heard that the 7.3 is a pretty simple engine and if I had the time to learn about them, I might agree. But, right now, It's looking about as simple as nuclear physics!

I have enjoyed this forum. I usually post up questions on Pirate4x4. They have some good advice but it always comes with a handful of attitude from the younger geniuses!

Thanks for the help. I'm sure I'll be back as I'm not giving up on learning about diesels, I just need to get this going sooner rather than later.
 

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I don't know if it has been mentioned in this thread but if you have a smart phone you are on your way to having a capable scanner for these trucks.

Then all that is needed is a download for Forscan Lite and a ELM327 bluetooth adapter to plug into the OBDII port and you are ready to go. Even if your OBDII port is not active yet a trip to a Ford dealer can activate it and then you will be a lot better off learning how to work on these trucks.

 

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The real "go-to" manauls for these trucks (in my opinion) are the Electrical and Vacuum Troubleshooting Manual (EVTM) and the Powertrain Control and Emissions Diagnosis (PCED) Manual. Do a really good inspection on the IPR wiring. It can get nasty with diesel leaks turning the wiring insulation to goo and causing shorts. Cheers!
 
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