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Discussion Starter · #1 ·
This truck is a 74 F-250 that someone did a Diesel conversion using a 1984 6.9 Diesel w/ 40,000 miles. I looked at this truck when it was for sale but I didn't buy it and at that time it was running fine. Know it is for sale again and the owner is saying that running rich and thats its not getting much throttle. Just wondering if anyone has any ideas what it could be or what to look for?

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Sounds as though there is an air restriction, check the air filter, and or the intake hose and piping. Check the easiest things first.
 

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Pull the return line off the injection pump and check for tiny bits of ground up o-ring material. If you find debris there you can sometimes get by with tearing the pump completely down and resealing it.
 

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What is the O-Ring made of?
It's not an o-ring, it's a fairly large and round piece of pellathane-plastic. It is a vibration dampener and holds part of the governor-weight assembly together. This plastic ring was totally eliminated in mid-1985. All pumps, regardless of age - when repaired are supposed to be updated and not have that ring anymore. All pumps built after mid-1985 came without it new.

The updated part is called an EID - stands for "elastomer insert dampener (or drive - I forget.
 

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It's not an o-ring, it's a fairly large and round piece of pellathane-plastic. It is a vibration dampener and holds part of the governor-weight assembly together. This plastic ring was totally eliminated in mid-1985. All pumps, regardless of age - when repaired are supposed to be updated and not have that ring anymore. All pumps built after mid-1985 came without it new.

The updated part is called an EID - stands for "elastomer insert dampener (or drive - I forget.
Geesh, now I see why I couldn't remember the proper terminology! :D
 

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Discussion Starter · #11 · (Edited)
I took a look at the truck today and I took a look at the air filter and it isn't cloged. The owner intsalled new glow plugs, starter and fuel filter. It seems like the motor is getting too much fuel and the alot of the fuel dosen't get burned. Any ideas?

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Discussion Starter · #12 · (Edited)
I talked to the owner today and he said that he didn't adjust the pump. The truck ran fine then it started the loose throttle slowly. He said the fuel pressure is 7psi. There was gray exhaust smoke that came out of it. He said that he can get it to stay running/idle. Any further ideas, I'm trying to see how much it may cost to fix?

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Did you pull the return line off the pump and find any debris in the outlet?
We aren't ignoring you but it is really difficult to figure out what the problem is from our end. You could have a bad injection pump, a fouled set of injectors, or quite a few other problems. Personally I think I would just forget about this one unless it was super cheap and I wanted an educational experience that I was willing to pay for. I'm not biased against Ford as I own a Crown Vic.
 

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Discussion Starter · #14 · (Edited)
He wants $3500 for it plus it comes with a lot of extra parts like 3 doors, grills, core support, hoods, 2 np205 t-cases and more. Plus the motor only has like 40k miles on it original. I like the truck, I just don't want to buy it then have to spend like 2-5k to fix it, I don't mind paying the $400 a new pump. I just don't want to have the motor rebuilt.
 

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I don't know if the truck is clean or not? I would guess that what he is asking for the truck in the condition it is in may be on the high side. Even with extra parts. Just make sure you know exactly what the problem is before you purchase it. It seems sometimes engines or vehicles with low mileage can have problems of their own that are just as bad or worse than one with higher miles
 

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Great idea, your much better of doing that than buying it not knowing and dumping more money in it than its worth. Let us know what happens
 

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Discussion Starter · #18 · (Edited)
I called the owner and unfourtanetly it is no longer registered, so I called a local Diesel shop and the guy said that by the symptoms I described to him, he said that it most likely is the Injection Pump.
 

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I would agree that it sounds like an injection pump from your description but without actual be able to look at the truck in person, its hard to say. Can you get someone to look at the truck with you that would be able to troubleshoot the problem? Just keep in mind it may be more than just a bad pump.
 
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