Recently purchased a 91 E-350 17 ft. box van, with the 7.3 IDI. Van has 185,000 miles. Engine runs smooth, and has been getting about 9.8 MPG on average. Problem is, it is very gutless. I have a similiar box van with a stock 460, and it will run circles around the diesel. Going 60 MPH, and stepping on it, takes FOREVER to get to 70. I have noticed that it seems wet on the intake, like it's leaking fuel, but I cannot locate where from. The metal lines from the injectors to the pump are good, with no leaks. Same with the rubber lines in between each injector. Possibly injector O-rings??? How about glow plugs?? Do they tend to leak fuel as well?? Would a small leak like this contribute to a power loss, or do I need to just start replacing injectors, and the pump with this many miles. Any help is appreciated!

 

With 185k miles you could have original IP and injectors still....... are the injectors and return lines painted OEM grey still.

Do you use a little diesel fuel additive, Power Service, Stanadyne etc. with every fill.

 

The lines are gray, as well as the tops of the objectors. Do you think fuel might be seeping out of these?

 

Forgot to mention that I put Howes in it every fill up.

 

Does is start right up when its cold?

 

No, I have to plug it in, or it has a hard time starting. Keep in mind that where I'm at, its usually about 20-25 in the mornings. Before it got this cold, it would start just fine.

 

The IDI has less power and torque. Without a turbo its not going to even try to run with the 460.

 

Even at 20-25* it should pop right off soon you turn the key!

Bill, the IDI has less power, but more torque than the 460 of the same years.

 

diesel tuneup:


"The 6.9 and 7.3 liter V-8 Ford diesel produced by International Harvester, uses an Indirect Injection fuel system, which consists of several parts, most notably of which are the Stanadyne manufactured model DB-2 rotary fuel injection pump, the steel fuel lines leading from this pumps output head, and which are connected to eight individual fuel injectors, which together, regulate, control, and supply fuel for the combustion process inside the engine. During the life of the engine, these parts are in constant use, as the injection pump rotates as part of the valve train, and the injectors fire once per power stroke of each cylinder. These parts, generally speaking, are medium wear items, and typically last about 100,000 miles. The main factor determining the lifespan of these parts is the quality of the fuel being used in the vehicle, and any additives that are being used. Due to the high tolerances inside the injection pump, a supplemental lubricity fuel additive is always recommended for longest life. Since the engine is rated for 300,000 miles, this group of parts typically requires replacement several times over the lifespan of the engine. This article will attempt to guide individuals engaged in the pursuit of this activity."

"A properly timed pump can make the difference between a great truck which the owner loves to drive and wants to keep, and a truck that the owner feels he may have wasted his money on."



followed by properly setting the timing:

"It's not a bad idea to have your timing checked every 20-30K miles. It's going to creep in the retarded direction as things wear, and fuel delivery for any given throttle setting is going to decrease. Fortunately as injectors wear, their pop presure lessens so things can sort of stay even, but there are no guarantees. "
-Mel


maybe not.but it doesn't need to get less than 10 mpg avg,nor take "forever" to go from 60-70 either.
it should be in the low teens avg minimum,and take just a few secs to go between 60-70 mph if you give 'er the oil.


pjohn,
the fuel leak your seeing is from the most common place.the O-rings under those plastic caps that snap on the injectors.
if you decide to swap the ip and injectors,you will then need an injector install kit.this will fix the leaks at the same time,as noted in the article in the top link.
no.this is not your performance loss.
should you be low on cash right now,and opt for a tune up at a latter date;
1.install a new injector install kit.
2.have the engine timed by a pro with a meter.
just know,the engine will need to be timed again,once you do install an ip w/injectors (or just one or the other.)

naturally the obvious items such as fuel and air filter need to be cleaned as well.
fuel filter replacement is every 60k miles or every 4 yrs.
air filter-this can vary.inspect it every oil change.toss and replace when dirty (or wash/re-oil a reusable)generally every 15k or 1 yr max.
the CDR also wants to be cleaned every other oil change.

the 6.9 and 7.3l are tough! they will keep running for a long,long time de-tuned.not like that 460.when she's had enough,she'll start knocking or pinging to let ya know she's overdue for a tune up.diesels not so much.they seem to just get doggy,and drop fuel economy over time.

the engine fans on these engine are energy hogs!!!
it's been estimated by one of FTE's finest,to rob you of 32 hp at the rear wheels.
the fan clutches can fail in the locked position is appears.do a search for "fan clutch test" to make sure yours is operating properly.OR as long as you hear it engage and disengage at the proper temps,your ok in this regard.

 

a well maintained IDI will pull circles around a 460 but the 460 will go faster.... at 185,000 miles your IP and Injectors could do with a replacement.... that will make a world of difference.... im still running stock IP and Injectors at 240,000 miles she still pulls better than any other truck ive towed with of similar years.... except the powerstroke diesel.... adding a turbo will make a world of difference on your top end as well

ive heard good things on here about pensecola diesel they have reasonable prices aswell

Pensacola Fuel Injection | Worlds #1 Diesel Rebuilder - FORD 6.9L - 7.3L :: REBUILT FUEL INJECTION PUMPS

 

So it seems that I am going to replace the IP, injectors, return lines, and glow plugs. I checked out Pensacola Fuel Injection, along with a few other sites, and Pensacola has the lowest prices by far. Only $108.00 for rebuilt injectors. My question is, do the prices reflect on the product? Should I possibly order from Midwest Fuel Injection, and pay a bit more?? Also, what is the normal operating water temperature for these motors, mine seems to always run around 190-200...

 

that sounds about right for mine in the summer somewhere near 200 you should be ok now in the last week we have had temps down in the -1 to -5 degree range and wind chills of -20 so its been around 175-185 depending if im driving into the wind or out of it.....

 

remember the ones your looking at on midwest fuel injection site are NEW and the ones for 108 on pensecola are REMAN there are some on pensecola site that are new but do cost close to the 230 dollar range for a set of 8

 

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