'74 Ford W/ 6.9L

[77gmcserria]

I'm looking at a 1974 Ford F-250 Camper Special XLT Ranger, it currently has a 6.9 Diesel with a C6 and a divorced NP t-case (203 or 205) and the diffs have 4.10 gears.

#1 The motor wont stay running, the owner says it needs a Injection Pump.

#2 How do I get the best mpg? I was thinking about changing the gear ratio and get with a 5 or 6 speed automatic or manual trans. Would that work. I don't do much highway driving. Any ideas?

Thanks

 

[BROWNIEBOY525]

welcome to the forum

How long will the motor run before it shuts off and will it restart after that.

 

[77gmcserria]

About 11.2 miles for about 25 min. one way. Then wont start up for another 8 hours.

 

[flatlander]

#1. Could be a pump, but there's a few things to check first. See if you have fuel pressure at the filter. There's a schrader valve on the side of it. With it running push it in. If you have air pressure followed by fuel, you have a leak somewhere. More than likely it's in your return system. Check for puddles on the intake manifold, wet return lines, trace the return line from the engine back to the tank. If you have no air pressure or fuel, it could be your fuel pump. Pull the feed line off the pump and see if there's suction. If there is you probably have a leak somewhere between the tank and the pump.. If not than you probably have a bad fuel pump.

#2. If you're not going to do much highway driving then I wouldn't change Didn't those years have linkage clutch systems? If you have a 203 transfer case then it's probably full time 4WD, isn't it?

 

[Exekiel69]

The no start could be many things but on the fuel economy the c6 is a good tranny that You can match with an overdrive unit like a gearvendor and get the best of the 4.10 gears with a nice overdrive.

 

[77gmcserria]

Correct the t-case is full-time 4x4, the trucks motor and trans is a 84, I don't believe the t-case is origional to the truck.

 

[Diesel JD]

Well the truck wasn't designed to get the best fuel economy. Anyone who cared to swap or even go after a unique non factory vehicle like that probably took good care of it. It sounds like the injection pump has a swollen hydraulic head which will run till it gets hot, then the tolerances internally get all out of whack and you can't restart. This can be verified by with the owners permission, applying lukewarm(Not COLD!) water to the pump on your next test drive when it quits or won't restart. This will shrink the clearances and reduce the swelling and you'll be on your way, until it gets hot again... That pump is toast most likely. The C6 and 4.10s MIGHT be capable of 12-13mpg in town and 14-16 empty on the highway if you stay below 60. Tow something and it will be 10-12. Add a GV or US Gear unit and it will be a lot better. What is the truck to be used for? If its just a toy buy it and don't worry about the fuel economy, if its going to be a DD and you want good fuel economy you're going to have to make some changes or look at a different truck, cause you aren't going to be happy with this thing if you need to get 18+ mpg as is.

 

[suv7734]

About 11.2 miles for about 25 min. one way. Then wont start up for another 8 hours.

Do you mean the truck just stops running or if you shut it down it won't re-start?

 

[towcat]

firstly,
welcome to the site.
second,
if you do get this truck, you are required to post pics.
now for the diagnosis.
1) if you get the truck warmed up after a 25 min drive and shut it down and can't restart, you have a problem with your injection pump.
2) you need a overdrive and convert the front axle to part time 4wd if you expect to gain any fuel economy. if you drive only in town and short distance, learn to live with it. both mods are expensive and only are worth if you do serious highway miles.
remember, pics are required;p

 

[flatlander]

Wow you guys are on it. When I posted there wasn't a single reply. You must have been replying at the same time as me. shoulda taken typing classes in school.

Like said if it starts right up and then shuts off, it's probably your pump. Not expensive and not too difficult. Do some reading here and ask questions.

Oh, and welcome to the sight.

 

[77gmcserria]

It doesn't run. You can't drive it, you turn the key then it just doesn't turn over.

 

[flatlander]

It doesn't run. You can't drive it, you turn the key then it just doesn't turn over.

This is after the 25 minutes of running, right?

Does it just die, sputter and die or what? Does it sound like it locks up suddenly? Once it dies can you bar it over with a 15/16" deep well on the balancer nut?

Interesting.

 

[77gmcserria]

Nope, its not after the 25 min of driving. It just wont start.

 

[flatlander]

Nope, its not after the 25 min of driving. It just wont start.

Back up a second. First you said it would run and then die, now it doesn't run at all? If it won't turn over at all, you can start into the starter system which is a solenoid on the firewall, a solenoid on the starter and a big old 2/0 cable to the starter itself.

 

[The Warden]

How much is he asking for the truck?

I tend to agree with towcat; it's PROBABLY the injector pump, and you could use that as a bargaining tool to buy the truck.

After you get the truck, there are a couple of things you can try. One thing would be to take off the elbow on the top front of the injector pump that the return line attaches to. The elbow screws into a check valve...you'll want to pull this check valve and make sure it's clean. If there are bits of black gunk in the check valve, the nylon gear in the governor assembly's coming apart, and it's definitely time for a pump.

The other thing you can try...I would only do this if you're pretty sure the pump's bad and you're already planning to replace it. After the engine's died in one of it's cycles, pour some cold water onto the pump (and be careful not to let any of the cold water get on any other part of the engine other than the valley pan), then see if the engine'll start up. If it will, that means that the pump's worn enough that, once it gets hot, the metal in the pump expands enough that the tolerances loosen up enough that it won't continue to function, and the cold water'll make the metal retract. HOWEVER...if you do this on a pump that isn't worn, you can end up ruining the pump.

Just some ideas...if the truck's in decent shape, I think I'd go for it as-is. And, in regards to fuel economy...as others have said, if you don't plan to drive on the highway on a regular basis, you're probably best leaving the truck as it is.

Welcome aboard!!!