7.3 HORRIBLE Fuel Mileage!!!

[SuperDirty7.3]

Hello all, newbie here from all the way out in Saskatchewan Canada!

Not to sure if you would be able to help me out but I got an odd Ford 7.3 question for you! (I have done a ton of reading so far and I see others have also kind of had similar issues but cannot find the exact issue yet!)

I recently picked up an 02 Ford F-250, Crew Cab, Short Box, 4" lift on 35's, other then that bone stock, no chip, straight piped. On the highway fuel mileage was alright for being bone stock, I did 180 K on 30 bucks so not to bad considering the lift/tires and cold weather.

I recently found out if you go WOT only sometimes it will throw a CEL, loose all power and almost fall on its face, lift the throttle up to about half gas and it will gladly take off and run fine again.

I scanned the truck for codes and it isn't throwing anything... I have read non stop and cant figure out this issue. I replaced the fuel filter today and the issue is still there. (Heard it may also be the filter in the tank or maybe the FPR?)

At first I thought maybe when the glow plugs were done that an injector wire got pinched but wouldn't that make an issue all the time and not only just under WOT? (Originally a wire did get pinched but Ford replaced it and supposedly all was good to go...)

Like I said, the issue isn't all the time, just sometimes under WOT.

Also the fuel mileage in the city is HORRIBLE. I have now done 240K and only have a quarter tank of fuel remaining, the truck was full to start. ... (I know 7.3's aren't a real gem on fuel but it shouldn't be this bad?)

I also let it warm up in the morning since it is quite cold here recently been about -25 (For the American's that works out to -13, I think!) I let it sit on high idle for about 10 minutes minimum or until the needle is off the white box on the temperature gauge. I don't think these warm ups should be harming my fuel mileage this horribly though!

Could anyone by chance please point me in the right direction?

Thank you everyone very much for your time!

[KMA Towing]

so far I am thinking clogged pickup tube screens in the tank restricting fuel volume... your pressure can be good with crappy volume...

second I am thinking CPS

I assume when you go WOT your RPM's climb.. you downshift... and you accelerate fine but then it craps out?

that to me sounds like a Cam Position Sensor starting to bug out.

as far as the mileage issue... can be related to either thing I listed... that and I am to sober to calculate Kilometers to Miles......

Good Luck to you eh!

[SuperDirty7.3]

Originally Posted by KMA Towing

so far I am thinking clogged pickup tube screens in the tank restricting fuel volume... your pressure can be good with crappy volume...

second I am thinking CPS

I assume when you go WOT your RPM's climb.. you downshift... and you accelerate fine but then it craps out?

that to me sounds like a Cam Position Sensor starting to bug out.

as far as the mileage issue... can be related to either thing I listed... that and I am to sober to calculate Kilometers to Miles......

Good Luck to you eh!

Thank you for the suggestions!

Today I was able to take it to a local shop and bring up the saved CEL codes. We then did an injector pulse test and the only issue was #5 low pressure.

He pretty much narrowed all the issues down to the CPS, he said he was almost 100% that is causing my issues with the intermediate power/no power and the fuel mileage.

Just went to Ford and picked up a new OEM Ford CPS for $60.00, I will instal tonight and hopefully that does the trick for me!


Thank you once again so far for the help.

[KMA Towing]

anytime

[Young-SC-Owner]

Don't forget to come back and let us know, more often than not we will give a list of things to check and one will fix it and the poster never returns with the results!


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[SuperDirty7.3]

Installed the CPS. Went for a drive down the highway, after doing a WOT pull it started to sputter and choke then stalled.

Checked the fuel filter and it was dry, added fuel primed a few times and finally fired up. Was running good until I hit 100kph (60 mph) then lost all power again. Now has 0 power and running horribly. Sounds quite fuel related...


Please Help...

[1BADTON]

Don't know how much you plan to spend but if you had no fuel in the filter bowl sounds like at least a new pump is in order.

[SuperDirty7.3]

The god damn fuel gauge must be out on me, said I had a quarter tank of fuel left and it ran out.

I put in 50 dollars worth and primed it a whole bunch and finally got it running again but the problems still remain, runs like it has a HUGE cam, no power, not even enough exhaust gases to spool the turbo.

Going to throw in the stock CPS in the morning and see if it all goes back to normal...


Will also drop the tank tomorrow and check the screens on the pump, the pump its self and check for fuel pressure.

[kendallcschm]

Originally Posted by SuperDirty7.3

The god damn fuel gauge must be out on me, said I had a quarter tank of fuel left and it ran out.

I put in 50 dollars worth and primed it a whole bunch and finally got it running again but the problems still remain, runs like it has a HUGE cam, no power, not even enough exhaust gases to spool the turbo.

Going to throw in the stock CPS in the morning and see if it all goes back to normal...


Will also drop the tank tomorrow and check the screens on the pump, the pump its self and check for fuel pressure.

to me that sounds kind of like and FICM in a 6.0L or i think its called an Injector Drive Module for the 7.3L, cause my truck blew smoke and sounded like it had a "big cam" or lopey idle.. which was cool to listen to but eh i'd rather have a functional truck

[Codum]

Originally Posted by SuperDirty7.3

The god damn fuel gauge must be out on me, said I had a quarter tank of fuel left and it ran out.

I put in 50 dollars worth and primed it a whole bunch and finally got it running again but the problems still remain, runs like it has a HUGE cam, no power, not even enough exhaust gases to spool the turbo.

Going to throw in the stock CPS in the morning and see if it all goes back to normal...


Will also drop the tank tomorrow and check the screens on the pump, the pump its self and check for fuel pressure.

What's to prime, if you ran out of fuel just add fuel, turn the key to the on position, if your fuel pump is running and the pick up screens not clogged the pump will fill the fuel bowl in seconds. If this is not happening then you have clogged screens in the tank or a bad pump.