'00 F250 7.3l diesel help

blasterr1 said:
Lurch, it seems like a constant variable that every time you hook up a different power source (another battery, charger, jump box, etc...) that your truck will start. I would first make sure that all your battery connections are good. Especially the passenger side battery positive. I scratched my head on this one time. Got a lot of the same issues (extended turning over time, faint clicking, buzzing from under hood) Drivers side battery would drop down below 10 vdc while cranking, passenger side still at 12 vdc. Only when i hooked up a jump box did it ever start. Then i found loose connection on passenger side. Hope this helps, all assuming you havent put batteries in the tool box yet, and still hooked up like factory.
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I have had that issue, one good one low. Spins fast, no start.

The computer has to see 10 or 11 volts? to fire. Can't remember the exact number.
 
Jeff B said:
I have had that issue, one good one low. Spins fast, no start.

The computer has to see 10 or 11 volts? to fire. Can't remember the exact number.
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Actually during cranking we often see sub 10v at the modules for a period of time. For the most part the modules will function down to around 8v, but the IDM will not be pleased about it. If you concerned you still have an issue with cranking voltage I'd suggest you do some research on voltage drop testing. This would be done from the b+ terminal to the starter terminal while cranking and the same would be done with computer power feeds.

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Adding to my frustration...truck fired up Monday afternoon (had it plugged in overnight & batteries charging). Drove it an hour to move more stuff out of my house, cranked up every time with no hesitation, took it to a diesel shop and did a injector buzz test & cylinder contribution test. Diesel shop's scanner said buzz test was good & said #3 & #8 injectors had faults...tech said #8 is always 'ON' due to a firmware update by Ford & said that I could use a new ICP sensor. I decided to hold off leaving the truck with him since I still needed to unload all my hunting gear & it was cranking without a hitch. Drove it to my parents & parked it for 1.5hrs, went to crank it after supper and it just spun over without cranking. I did notice that when it doesn't crank the tach needle hangs around zero, but before it cranks its bouncing around 500RPM. I'm probably going to throw a CPS & ICP in it since I can do those quickly during the oil change this weekend. If it still has problems, should I replace all 8 injectors? If so, are there any oversized injectors that I could install without having to mess with the tune?
 
Lurch830 said:
Adding to my frustration...truck fired up Monday afternoon (had it plugged in overnight & batteries charging). Drove it an hour to move more stuff out of my house, cranked up every time with no hesitation, took it to a diesel shop and did a injector buzz test & cylinder contribution test. Diesel shop's scanner said buzz test was good & said #3 & #8 injectors had faults...tech said #8 is always 'ON' due to a firmware update by Ford & said that I could use a new ICP sensor. I decided to hold off leaving the truck with him since I still needed to unload all my hunting gear & it was cranking without a hitch. Drove it to my parents & parked it for 1.5hrs, went to crank it after supper and it just spun over without cranking. I did notice that when it doesn't crank the tach needle hangs around zero, but before it cranks its bouncing around 500RPM. I'm probably going to throw a CPS & ICP in it since I can do those quickly during the oil change this weekend. If it still has problems, should I replace all 8 injectors? If so, are there any oversized injectors that I could install without having to mess with the tune?
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Clearly a new set of injectors will improve driveability, fuel mileage and it will likely run smoother and quieter. But in my opinion it would be rare to have a no start caused by injector faults. Unless I had data to suggest a fault here, it's not likely that I would consider injector replacement to address an intermittent no start fault.

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mysterync said:
Clearly a new set of injectors will improve driveability, fuel mileage and it will likely run smoother and quieter. But in my opinion it would be rare to have a no start caused by injector faults. Unless I had data to suggest a fault here, it's not likely that I would consider injector replacement to address an intermittent no start fault.

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He brought that up to, but said if the poppet valve failed open the HPOP wouldn't have anything to build up pressure against which wouldn't let it fire. I'm not a diesel expert by any means, so I'm just sharing info & trying to get my tow pig reliable in case I decide to daily drive it in Raleigh.
 
That is certainly possible, but it's rare and it's extremely easy to test. Without testing it's guessing, I feel you'd find yourself more frustrated if it didn't fix it. That being said, if it's never had injectors its probably worth while to throw a set in it!

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mysterync said:
That is certainly possible, but it's rare and it's extremely easy to test. Without testing it's guessing, I feel you'd find yourself more frustrated if it didn't fix it. That being said, if it's never had injectors its probably worth while to throw a set in it!

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I realize every case is different and results vary but how many miles can you “typically” get out of set of inj’s ???Mine has about 286k on em.I’ve put over half of those miles on myself so I’m guessing it still has the orig sticks in it.


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We've seen original injector with random single replacements we'll over 300k. I think the biggest issue with this is the performance degrades over time. At 120,000 you could put a new set in and see a slight improvement. At 250k you could put a new set in and it would feel like a new truck! Now, in today's world if I suggested to every owner that they be replaced as a maintenance item I'd probably get a lot of flack for that. Our suggestion is replacing them as a set if a failure occurs at higher mileages without evidence or records to suggest they'd been previously replaced.

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mysterync said:
That is certainly possible, but it's rare and it's extremely easy to test. Without testing it's guessing, I feel you'd find yourself more frustrated if it didn't fix it. That being said, if it's never had injectors its probably worth while to throw a set in it!
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I'd be frustrated that it wasn't fixed & irritated I spent that amount with no results! I'm the 2nd owner, so my guess is original glow plugs & injectors.

1-tonmudder said:
I realize every case is different and results vary but how many miles can you “typically” get out of set of inj’s ???Mine has about 286k on em.I’ve put over half of those miles on myself so I’m guessing it still has the orig sticks in it.
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The guy said the same thing thinking 116k is low miles for needing injectors. I'd just hate to drop that kind of coin for it to essentially be throwing $$$/parts at something hoping it sticks.
 
mysterync said:
We've seen original injector with random single replacements we'll over 300k. I think the biggest issue with this is the performance degrades over time. At 120,000 you could put a new set in and see a slight improvement. At 250k you could put a new set in and it would feel like a new truck! Now, in today's world if I suggested to every owner that they be replaced as a maintenance item I'd probably get a lot of flack for that. Our suggestion is replacing them as a set if a failure occurs at higher mileages without evidence or records to suggest they'd been previously replaced.
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Word for word what I was told! He said if you replace individually, the IDM will overdrive the older ones to try and match performance & cause them to fail faster.
 
Lurch830 said:
I'd be frustrated that it wasn't fixed & irritated I spent that amount with no results! I'm the 2nd owner, so my guess is original glow plugs & injectors.


The guy said the same thing thinking 116k is low miles for needing injectors. I'd just hate to drop that kind of coin for it to essentially be throwing $$$/parts at something hoping it sticks.
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Id say the probability of that "sticking" is under 20%.

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Have you replaced the valve cover gaskets? Seen that cause some intermittent problems since the injector harness in made into the gasket. They’ve been known to have broken wires in the middle somewhere. You could pull the covers and check continuity between the injector and the corresponding pin at the plug. Just a thought.
 
Oh and might try switching to a 5-40 synthetic oil. Switched a lot of 7.3s and 6.0s for fire departments at work that were running poorly and it made pretty good improvements in most of them. I know that’s not your problem but that weight flows way better in cold weather in HPOPs.
 
lbyota85 said:
Oh and might try switching to a 5-40 synthetic oil. Switched a lot of 7.3s and 6.0s for fire departments at work that were running poorly and it made pretty good improvements in most of them. I know that’s not your problem but that weight flows way better in cold weather in HPOPs.
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I run that in almost everything.
 
So last week I ordered a new CPS & ICP sensor (because why not?), but they didn't get here until Tuesday due to the holidays & I was packing up to head back to Raleigh. Here's the kicker though...truck cranked and ran great every time over the long weekend without it being plugged in, but the new batteries were connected during start-up. I'll be out of the state over New Year's, so I'll swap the CPS & ICP sensor the following weekend along with the oil change I haven't got to yet & make the new battery connections permanent instead of using jumper cables.
 
Lurch830 said:
So last week I ordered a new CPS & ICP sensor (because why not?), but they didn't get here until Tuesday due to the holidays & I was packing up to head back to Raleigh. Here's the kicker though...truck cranked and ran great every time over the long weekend without it being plugged in, but the new batteries were connected during start-up. I'll be out of the state over New Year's, so I'll swap the CPS & ICP sensor the following weekend along with the oil change I haven't got to yet & make the new battery connections permanent instead of using jumper cables.
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I still thinkb it's a low voltage issue
 
Jeff B said:
I still thinkb it's a low voltage issue
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I agree & I'm beginning think its 100% of my problem. I tested it by having my dad try to crank it over the weekend without the new batteries connected while I was standing ready with the jumper cables. It spun for ~15 seconds without firing before I made contact with the jumper cables. Made contact & it seemed to pick up speed (could've been in my head)...spun another 2-3 seconds and fired right up. Also, I parked it at my hunting property one evening for 1.5-2 hours...spun right over & cranked using the OEM batteries under the hood. So a battery terminal cleaning session is a must!
 
Lurch830 said:
I agree & I'm beginning think its 100% of my problem. I tested it by having my dad try to crank it over the weekend without the new batteries connected while I was standing ready with the jumper cables. It spun for ~15 seconds without firing before I made contact with the jumper cables. Made contact & it seemed to pick up speed (could've been in my head)...spun another 2-3 seconds and fired right up. Also, I parked it at my hunting property one evening for 1.5-2 hours...spun right over & cranked using the OEM batteries under the hood. So a battery terminal cleaning session is a must!
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If you have an Amp probe, check the draw and inrush of the starter. May give your some insight. Dielectric grease on both ends battery/starter would be a good attribute.
 
I changed out battery cable ends on my 99, it made a big difference on how it spins over
The passenger side cable was getting corroded up against the big factory end
 
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