7.3 diesel F250 99

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Our truck started acting up, we changed the wiring harness, because someone said that could be it, then the alternator went dead, had to replace that. It misses under a load, and last weekend it just would not go at all. We had it put on a computer about 2 weeks ago, that guy said the 8th injector was bad-question is, will one injector make the truck totally die? The 8 th injector on this truck is different than the other 7, its a long bore, and the most expensive. We should have had the diagnostic test run, but thats pricey and we are on a pretty tight budget. Now I wonder do we replace the injector, replace the fuel pump and hope thats it, and then what if its not-anyone ever have Frd diesel do something like this?

Thanks
 
7.3's don't have a fuel pump. They have a high pressure oil pump that pressureizes the fuel. It sounds like it's the injector harness or harnesses. I would check those before I bought injectors. IMO if your in there replace all the injectors.
 
sounds to me like its either the cps(50 bucks and a 10mm bolt) or the high pressure oil pump. the hpop needs to be tested to verify via the comm port and reader while cranking. a single injector will not make the truck not fire
 
hooknline":2tk7jlvc said:
sounds to me like its either the cps(50 bucks and a 10mm bolt) or the high pressure oil pump. the hpop needs to be tested to verify via the comm port and reader while cranking. a single injector will not make the truck not fire
Click to expand...

Good idea I didn't even think about the cam position sensor. I sounds dumb but my dad brought me his 7.3 truck saying it was running like crap and would just turn over and not crank. I started checking things after about 5 mins I checked the oil. I don't remember how low it was but it was pretty low. Filled it up and ran like normal again. I called him a big dummby and he felt pretty stupid.
 
you can swap the cps with a known good one and if that doesnt fix it my bet would be hpop or the orings on the fitting to the hpop lines. do you have a leak that appears to be a rear main? if so it could be the lines leaking down the valley and to the rear down the block. it has to build some pretty high pressures to drive the injectors. if it gets worn the pressure bleeds back and dont drive the injectors and you get no fire. bad news is its not cheap to replace
 
Anything I've ever had to do with diesels, when they start missing and stop especially, it is always air getting in somewhere and they need bleeding. Before spending too much I would check the basics, make sure all unions and joints are tight, the pickup from the fuel tank etc is all good and no possibility of sucking air. They may have all the mod cons and computer controls on them, but they are still just diesels.
 
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Cam position Sensor was recalled, should be free at the dealer. I bought an extra one because they have a problem going out at the worst time, easy to replace, just need a deep 9/16 socket (as I recall).
#8 injector is ALWAYS the one to go out on the 7.3! Chronic problem. I believe there is a way to test the injector without running a full diagnostic, but I'd have to ask my buddy whose a Ford diesel mechanic.
May have damaged the injector by running low on oil, luckily the 7.3 has a low-oil-shut-off, so you may not have run critically low.
 
If the tach jumps around a lot be sure to check the cps. The harness in those going to the injectors is actually in the gasket, they give problems because of the glow plug wires run in the same harness usually see connections melted in the connectors. You can buy the stuff cheaper at international dealer than you can at Ford. Diesel Stop forum has a ton of info.
 
I bought the 8 th injector yesterday, gonna replace it and the fuel filter, that is what I meant to say originally, instead of the fuel pump.We did have the recall for the cam sensor, had that fixed by the dealer and do have a spare as well. I'm hoping it will be the injector, if not a guy we had work on our Oliver will look at it, and run the diagnostic on it-but this would be the cheap fix-so keep your fingers crossed!

Thanks for all the suggestions, I will make notes on them-
 
High Cotton":170z318h said:
7.3's don't have a fuel pump. They have a high pressure oil pump that pressureizes the fuel. It sounds like it's the injector harness or harnesses. I would check those before I bought injectors. IMO if your in there replace all the injectors.
Click to expand...


It wasn't the injector harness, replaced that first
 
We haven't replaced it yet, as we are cutting a hay job we need to get done this week, hopefully this weekend
 
We replaced the 8th injector and seems to have done the trick-truck running as it should again-
 
I've found that many so called mechanics dont know sheet about anything mechanical except changing parts. There are several Diesel websites that share information about your Diesel truck. The information is available and I'ts free for the asking. Believe me or not, you're not the only person that has diesel problems.
Diesel Bombers.com
Oil Burners.net
Competition Diesel.com

If you try these web sites you may solve your problems with very little cost.
Good luck and I am sorry you are having difficulties with your Diesel
Kerley
 
i had trouble with my 99 7.3 last year ,i woke up and someone stole it out of my driveway. Took the motor and trans and then burned it. Rode like a truck and sounded like a truck and never a major problem.
 
Did you ever put it on the computer to see what codes were stored or if the cps and hpop parameters were within spec?
 
Its getting a diagnostic run on it today-so we will see once and for all. Whats weird about it, is it drives normal good, under a load it shakes the whole truck, BUT not everytime-so at this point I will be glad to just know whats wrong with it, thats IF they can figure it out-
 

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