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View Full Version : my mileage sucks, powerstroke 7.3


stumper1620
03-06-2005, 08:16 AM
ok, i don't need to hear about duramax or cummins, this is what i got.
I bought this truck new in nov. 02, the last of the 7.3s, 6.0s were on the lot.
started out new with 18 and up mpg. ever since it has steadily fallen off to the point of 2 weeks ago, I went on a trip to get a new used WB, i left home with a full tank, figured i could make it there & back no problem, wrong!
pulling my 16' trailer I got 9.7 mpg, half the trip the trailer was empty and on the return it only had 1 36"wb on it. This is the worst milage i have ever gotten other than plowing in big storms. It has been suggested to me that maybe my torque converter is not locking. if this is the case I sure dont feel a difference when driving. any Ideas, and please don't tell me to get rid of it. at this time it is not in the plan so that is not possible.
oh ya, and during daily use with no load or trailer its still only about 14 +or-a little.
Is this normal or is something wrong, dealer said its normal.

xcopterdoc
03-06-2005, 09:32 AM
Any other clues.. such as loss of power, hard starting ect..??

LawnsUnlimited
03-06-2005, 09:38 AM
Any other clues.. such as loss of power, hard starting ect..??

I have had loss of power and hard to start with crappy mileage.

bsnead
03-06-2005, 09:43 AM
check your fuel filter

stumper1620
03-06-2005, 09:43 AM
Any other clues.. such as loss of power, hard starting ect..??
starts great, idles & runs out great. may have a minor power loss, i kinda think its getting weaker, seems like it requires a lot more pedal for the resultinng power as compared to prior use, as i said this is a steady decline,
I have documented every fill up and resulting mileage as well as noting circumstances (pulling trailer, extreme cold ect.)
I just about died when told this is normal.
oh details, 3:73 gears, a/t super cab, stock tires and i replace the air filter at every other oil change 4k per oil change, 90% highway miles, just turning 70k

xcopterdoc
03-06-2005, 09:52 AM
In order to really pinpoint the problem you are going to have to take it to a dealer or another shop that has the proper diagnostic equipment.
I would change the fuel filter to begin with and see if that makes a difference, if no change then off to the shop for a proper look see at all the injectors and other engine controls to include turbo charger.

stumper1620
03-06-2005, 09:57 AM
In order to really pinpoint the problem you are going to have to take it to a dealer or another shop that has the proper diagnostic equipment.
I would change the fuel filter to begin with and see if that makes a difference, if no change then off to the shop for a proper look see at all the injectors and other engine controls to include turbo charger.
service manager at the dealer said its normal. I don't buy that and i'll take it to another dealer but, can you give a guess what should be normal mileage?

stumper1620
03-06-2005, 10:00 AM
one other question for you ford guys.
powerstoke 100k warranty, will it cover this as long as its not a reg. mainiance item causing the problem? just curious about that.

grass_cuttin_fool
03-06-2005, 10:04 AM
A dirty air filter can really cause problems on a diesel, and the winter blend of fuel doesnt help either. Some places mix kerosene or have it refined with less wax and it doesnt have the btu's that straight diesel does. At about 25 degree's untreated diesel fuel begins to seperate from the wax and that stops up your fuel filter. Also check your air pressure in the truck and trailer tires also, in the winter lower air pressure creates more drag which means higher fuel consumption. On a site somewhere the other day, I dont remember where, A certain brand of truck is bad about the rear brakes sticking or not releasing 100% and creating enuff drag that the fuel economy is going down. Also could a trailer brake be acting up and creating extra drag?

stumper1620
03-06-2005, 10:12 AM
A dirty air filter can really cause problems on a diesel, and the winter blend of fuel doesnt help either. Some places mix kerosene or have it refined with less wax and it doesnt have the btu's that straight diesel does. At about 25 degree's untreated diesel fuel begins to seperate from the wax and that stops up your fuel filter. Also check your air pressure in the truck and trailer tires also, in the winter lower air pressure creates more drag which means higher fuel consumption. On a site somewhere the other day, I dont remember where, A certain brand of truck is bad about the rear brakes sticking or not releasing 100% and creating enuff drag that the fuel economy is going down. Also could a trailer brake be acting up and creating extra drag?
i know air is vital to dsl, used to drive big trucks,got better mileage from my frieghtliner. anyway like i say i change air filer more often than needed but i like my motor to breath good, the fuel filter is going to change tomorrow.
thanks, still would appriciate an est of normal. this service manager is in the same auto group i used to work for. really burns me if he is lying.

xcopterdoc
03-06-2005, 10:38 AM
I would say... 15 to 19 unloaded.. as low as 9 if you are pulling a really heavy trailer.

stumper1620
03-06-2005, 10:46 AM
I would say... 15 to 19 unloaded.. as low as 9 if you are pulling a really heavy trailer.
thanks xcopterdoc,
that's what i wanted to see, i sure don't see how he could call what mine is as being normal. :D
basically where my mileage started is where it should still be. right?
how about warranty any idea?

twwlawn
03-06-2005, 11:09 AM
I have a 1996 that did the same when I got it. When that happened, my service center recommended that the fuel filter be changed out every other oil/filter change and check/ replace the air filter more than normal. I also have the injectors flush/cleaned and engine flush done annually. Since doing this, my mpg has gone up and remained. I also had a cold air system, 3" down pipe with 4" exhaust system and chipped and that has really increased the performance.

stumper1620
03-06-2005, 11:14 AM
I have a 1996 that did the same when I got it. When that happened, my service center recommended that the fuel filter be changed out every other oil/filter change and check/ replace the air filter more than normal. I also have the injectors flush/cleaned and engine flush done annually. Since doing this, my mpg has gone up and remained. I also had a cold air system, 3" down pipe with 4" exhaust system and chipped and that has really increased the performance.
i've heard about the exhaust being restictive. i just kinda want to rot out the old before forking out the bucks on a 4" & chip.

twwlawn
03-06-2005, 11:30 AM
i've heard about the exhaust being restictive. i just kinda want to rot out the old before forking out the bucks on a 4" & chip.

Replacing the cobra tube with the 3" down pipe allows better flow. Find a couple of places where you live that deal directly with power strokes and get some different opinions. I have my truck hooked up to a diagnostic machine twice a year just to make sure it is running like it suppose to be.

Gilla Gorilla
03-06-2005, 11:36 AM
As far as your question of it being covered under the Engine warranty, It is impossible to say yes or no that it will be covered with 100% certainty. Call Ford customer assistance and explain to them what is happening and ask them for the name and number of a Ford dealership that is reputable and effective when it comes to fixing PSD's.

Go into that dealership with an appointment and authorize them 1 or 2 hours of diagnostic time, probably will be between $90.00 to $200.00 for this. If and when they find anything wrong they will check the PSD engine warranty coverage chart and see if the part or parts are covered and hopefull be able to give you the good news about it being covered under the 100k warranty.

Good luck

stumper1620
03-06-2005, 11:49 AM
thanks guys,
I'll do the fuel filter tomorrow, run a couple tanks thru it, and see where it goes. i changed my fuel stop at the first of last week to see if maybe it was fuel problems, I'm buying off big truck pumps only now. If i dont see any improvement after the filter i will get it in the shop, at 2.20 a gallon this is going to kill me this year. its already digging in to theplow profits pretty hard and that don't involve dragging a trailer around the world like my summers do.

xcopterdoc
03-06-2005, 05:13 PM
As far as warrany goes.. Ford is really fickle... the worst in my opinion. Some dealers are better than others at eating some of the cost if you are a good long time customer. If not... yur on yur own. The dealer makes his money, the customer and the tech working on it both get screwed.

stumper1620
03-06-2005, 07:02 PM
As far as warrany goes.. Ford is really fickle... the worst in my opinion. Some dealers are better than others at eating some of the cost if you are a good long time customer. If not... yur on yur own. The dealer makes his money, the customer and the tech working on it both get screwed.
I hear ya,
thats why i'm not a tech anymore.

lwcmattlifter
03-06-2005, 09:35 PM
How many PSI is you fuel pump making? I'm not sure about the 99+ but on the 94-97PSD there is a screen in the fuel regulator that can get clogged. Also try unplugging your MAP sensor on the firewall and see if it runs better. Did the truck throw any codes when the dealer scanned it?

stumper1620
03-06-2005, 09:47 PM
How many PSI is you fuel pump making? I'm not sure about the 99+ but on the 94-97PSD there is a screen in the fuel regulator that can get clogged. Also try unplugging your MAP sensor on the firewall and see if it runs better. Did the truck throw any codes when the dealer scanned it?
hasn't been scanned yet, never had a light to indicate a problem, just can't get any mileage. like i said on a earlier post, my frieghtliner with a 350 cummins did better draging a 52' 13'6 wagon behind it. this is in my opinion pretty bad. :realmad:

lwcmattlifter
03-06-2005, 11:17 PM
I would start by running with the map sensor unplugged to see if you get better mileage and power. You will get a CEL but it wont hurt anything, the truck wont be able to see any turbo boost so it will run in default mode. 2nd I would check fuel pressure. You should have 45psi at idle and it should not drop that much when you are reving the engine. Are all the boots on the intercooler sealed? Also check to make sure the intake clamps are tight.

TerraVenture
03-07-2005, 06:16 AM
I can't offer a whole lot in advice with what is wrong but to give you an idea of mileage. I have a 1996 f350 Rack body dump with a full cab protector ( huge aerodynamic drag), 4:10 gears, 4x4, 140k miles. It usually is hauling a 20 ft enclosed half full ( estimated 6000lbs). I get 12mpg with this configuration. Last winter I took the sides and cab protector of the body and didn't haul a trailer and i was averaging around 16mpg. I also have a 2004 F550 4x4 6.0 diesel, mason dump, 4:88 gears,15k miles. It averages 10mpg loaded or unloaded. The cab protector destroys the mileage on dump bodied trucks. I shoud think that and unloaded pickup, with 3:73 gears, should be getting between 17 and 20 mpg. Even fully loaded it should be getting 12 to 14mpg.

big_country
03-07-2005, 07:30 PM
Chevrolet 3500 with the 7.4 liter 454 4x4, 8.5 mpg unloaded city or highway doesn't matter, loaded about 8 mpg or just under doesn't matter if it's 2k or 20k. The best I've got is about 10 mpg down the highway, the tail wind must of been good that day. But I have a buddy that as a 92' f-250 with the 7.3 stroker and he had an automatic and got about 15 unloaded, he put in a straight shift after 3 transmissions and now only gets about 9 or 10 mpg unloaded, don't ask me.

BOTURF
03-07-2005, 07:39 PM
i have a 96 chevy 3500 dually 454 2 wheel drive and i have gotten 13 on interstate and around town unloaded i get 11 or 12 loaded i get 10 i also just got a 01 chevy 8.1 liter and only drove it unloaded and got from 10 to 11.5 mpg

big_country
03-08-2005, 03:51 PM
Yea, I had a 97' 2wd ext-cab 3500 with the 454 and usually got about 12 or so outta it.

ftgull
03-26-2005, 10:47 PM
if the ebpv is sticking it could cause this, My 97 f250 4x4 with 33's towing 8000lbs will still get 14, 15 and with nothing 16, 18, and this truck has 205,000 with a auto tranny