Hey everbody, long time reader first time poster. MPG issue
93 f250 2wd 7.3l e40d 4:10 supercab longbed 143K miles. Last comp.test showed 435-450psi in each, when i took my first few road trips with this truck I was getting 19mpg camping dirt roads and freeway driving at 70. 3-4 months later it dropped to 13.5mpg. I took it to the dealer for a vibration, that turned out to be U joint. They had said that the injector pump was leaking indicated by the fluid at the flywheel cove tube (something was leaking, oil). I had a few other shops take a look and they agread (greed) Pump was pulled out and replaced (it was dry by the way, no leaks) I was new to diesels and a little intimidated.
Since then I've been turning my own wrench. I've made alot of modifications to this truck and always remained at 13.5 MPG. modified intake K&N (looks like an octopus) I've got three 4" intake tubes. 1 is over the battery (stock) 2 at drivers side radiator (86 diesel intake) 3 at passenger side radiator (modified from over battery) soup b. is gone. 13.5 MPG. Had a shop make an exaust for me. New Y pipe true 2.5" smooth flowing drops into a 4" pipe straight through muffler. sound very nice 13.5 mpg. New Injectors Stanadyne D style. E style were standard for 92 1/2 - 94 pre power strock (any body know what the difference between these injectors would be?) I'm still awaiting the results of the injectors. My next change is 3:55 in place of the 4:10. I have a small tool trailer that I haul almost daily 1200-1800 lbs and a 3000lbs empty dump trailer. When the dump is being hauled it drops my millege in a very big way (expected) my top millege on free way in the past month has been 16.5 mpg.
at 65 2100rpm. I mentioned oil leak earlier looks like its coming from the head gasket (not valve cover) on left and right side of engine. valley pan drain was plugged but no puddle. when I look with a mirror it is wet where the iol pressure sending unit thread into the block. runs like a top just need a little better millege at $2.40 gal every little bit helps.

Thanks in advance for your time and comments. This is a very helpful site with generous people.

Rhino

P.S. my foot has been consistent, but it does have alot of ***** (the truck, not the foot)

 

Stanadyne Corp. answer.........

There are three different injectors used in 6.9 & 7.3L engines - one for the 1984-1992 6.9's & 7.3's, one for the 1992 1/2 - 1994 engines that Navisatar referred to as the "P&E" (performance & emissions) engines and one for the 1994 turbocharged engines.
In reviewing the drawings I see that in addition to to different nozzle opening pressure for the injectors, there are a number of differences between the nozzles including:
different pintle diameters, pintle bore clearance, valve overlap length,valve extension etc. all which result in different valve lift vs flow characteristics and therefore result in the different injectors for the different engine applications."
Sincerely,
Mark Dionne
Manager, Product Support
Stanadyne Corporation

The D injectors have a lower break point pressure 1800-1950 which match the older 6.9 and 7.3 engine IPs.
The E injectors have a higher break point 1925-2075 and they match the lower RPM 5013 pump on the 92.5 motors. You would be wise to run the injectors for your engine and IP. Look on the tag on the timing gear cover for engine ID.


EDIT the oil leak can be from the sender, it is screwed into an extension. Be carefull as full battery power is at the controller. Clean the area well before removing the sender and extension, only use a liquid Teflon sealant do not use teflon tape. Also check the valve cover bolts for tight, 6ftlbs.

PLC7.3

 

Thanks PLC7.3 I will look into that. Is there a part # I should look for on the IP pump which will indicate which year it is intended for. I had that replaced shortly after I bought the truck.

 

Where are you at?
If the drop has been close to colder weather and you are in the northern US the fuel may be #1 and #2 blend in preperation for winter temperatures.

This is common practice for the oil companies to prevent fuel gelling.

The #1 diesel contains less parafin wax than #2, but it also contains less BTU's per gallon. Therefore it takes more fuel to create the same amount of power.

Way down south is about the only place the fuels are not blended to some degree in the winter. This is a mixed blessing, you do not have to add as much fuel suppliment as long as temperatures are close to normal, but you pay for it in mileage and power loss.

That trailer is responsible for about 2 MPG or more loss alone. The weight will cost you close to 2 MPG and when you say tool trailer I am guessing it is a box trailer that catches lots of wind which will drop it even farther.

Does your exhaust come together as a 2.5" or does each manifold pipe hook directly into the 4" pipe?

 

Yes there is a tag on the pax side with all the info, you may see punched #s on the body those are rebuilder IDs and dates, if there are lots that pump has been around.........look for 5013.

 

Dave

I'm in Oregon. I realy don't think the fuel had anything to do with the drop. It has not changed in over a year. The Y comes together in the transition from 3 to 4 inch.

I purchased the injectors from shopdiesel.com and the only option for injectors for my year truck was between turbo and non turbo.

 

PLC7.3
Went out and looked and found the 5013. Do I need to send these injectors back?
If so where do I find new E style?

 

I would call first for an OK then send them back for a refund.

I think both these places handle them:

http://www.mwfi.com/ford_73.htm

http://www.dieselpage.com/fuel.htm

Might as well get a new return line kit too. They will come with new orings and copper seals though.

 

PLC7.3
Thanks for info. New return lines were installed when the pump was replaced.

 

The return line caps will start leaking when you change the injectors. It is only a few more dollars to change the O rings while it is apart. Saves lots of time removing them in a week when they start leaking. Since the lines were replaced I might skip changing them, but with my luck I would probably change them also since they will be apart.

 

Changing the orings had helped with my 'wet' injectors.
When you change them out, undo the entire row of lines, then pop off the return 'tees' all at the same time for that side.

When I tried them one at a time (to avoid dirt of course) I found I cracked 2 of the tees right at the nipple for the return lines. Not fun.

Either way, I did not see a mention of the fuel filter being changed, but I assume it was.

Oh yeah, almost forgot. Definatley, the IP for the turbo and non turbo IDI 7.3L is different. But if your already looking at the injectors, then you might have already checke dthat out as well. I only mention that cause you say the IP was changed, it may be not the same as what initially you had been getting the 16.5 MPG on.

 

Dave

What is your view on the injectors D vrs E style? I looked at site given by PLC7.3 and I wish I would have found that 2 weeks ago, should have posted sooner. My hayes manual states that injection pressure did not change until 94. This could be a situation where I have just enough info to put me in danger.

 

Which Haynes manual is your info from..............??

 

PLC7.3 Sorry my mistake. It's not a Haynes. Chilton #26664 covers 1987-1996 gas and diesel. DIESEL Engine Tune up specs states 87-93 injections nozzle pressure New 1875 used 1425 in 94 they change to: new 1900 used 1450. The other manual I use is Haynes Techbook #10330 Diesel Engine Repair Manual. It deals with GM & Fords through early powerstrokes. But it makes no mention of injector codes or differance.

Ironpants, Initially I was getting 19mpg now my best is 16.5mpg
Dave, The tool trailer is a compact Fruehuef 4x6 it slipts right behind my truck. I have an arrow canopy and it seems to me that the trailer would fit in the air envolpe created bu the truck. I do see a slight drop when I haul the tool trailer. 16.5 mpg is my best not trailer 65mpg

 

The E style injectors being higher pressure will do a better job of atomizing the fuel. This in turn will get a better burn of the fuel.
If you have the 5013 pump I would see about using the E style injectors.
That higher pressure pump with your old injectors that were weak from the years probably did strange things to the spray pattern. Which may be where the extra MPG's went.