# 7.3l powerstroke vs 5.9 Cummins



## DAFFMOBILEWASH (Dec 9, 2006)

Have a new to me 01 f350 2wd which I love but hate all at the same time. The truck empty is nice driver but the fuel milage wont crack 15mpg. The power band of this truck too sits way above my normal comfort levels too. Truck needs 2000+rpm to feel any subsancial power and seems like its working too hard to me.

Now for what really bothers me is the pulling power of the truck. The other day with a stiff head wind pulling a 5000lb dump trailer the truck was nearly at its max. Had to almost floor the truck to get up to speed. 90km/h ... I have changed all the fluids filters and high pressure oil in the top end in efforts to wake the engine up.

Does this sound somewhat like a typicial 7.3l?? Or is the issue that I am just so use to the power band of the 5.9l my right foot needs to learn to get more into the diesel. Perhaps there is someone else out there who has owned both...


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## Milwaukee (Dec 28, 2007)

Sound like boost leak.

Is intercooler pipes with boots are saturated in oily?

15 mpg it pretty bad. My 00 F350 4wd get 18 most time.


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## DAFFMOBILEWASH (Dec 9, 2006)

Is there a typicial place where they fail ?? Would you hear a hissing sound ???


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## Milwaukee (Dec 28, 2007)

Too many to list. I end replaced all boots because preview owner drove with them for long time.

Check this for information 
http://www.ford-trucks.com/forums/1049557-boost-leak-detector-pics.html


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## WilliamOak (Feb 11, 2008)

I've towed with 7.3s many times and hopping in one after driving any of the big 3's newer diesel's they do feel like dogs but definitely not to the extent you seem to be experiencing.


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## tjctransport (Nov 22, 2008)

something is definitely wrong. my 02 7.3 will out pull all of the dodges in town except for one, and that is a built pulling truck.


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## allagashpm (Sep 29, 2012)

I had a leaking down pipe as well, when I fixed that and all the seals it made a huge difference. 15 mpgs isn't terrible though, in the summer I usually get around 16 with 285s, now you have the winter fuel which kills it.


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## DAFFMOBILEWASH (Dec 9, 2006)

Would an engine smoker work ?? Have a friend who is a mechanic and helped him put it on a 3.8l chevy checking for intake leaks... Such a great tool too. Sorry Mrs Smith you need a intake see this smoke billowing from here ???


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## Antlerart06 (Feb 28, 2011)

Gears plays a factor in the power you put on the ground
I ran one ford had 355 gears and that pulled like a turd 
I have one has 373 and 15-16 best I can get I run a programmer bigger turbo
I have it set most time for towing


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## clark lawn (Oct 7, 2005)

Best thigh is to install a boost gauge and a pyrometer.


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## 2COR517 (Oct 23, 2008)

Even I can say the performance doesn't sound correct. I occasionally drive a 98 E350 7.3 with 200k. Power really isn't an issue.

I agree a boost gauge would be a good place to start. And the smoke machine should identify leaks pretty quickly.


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## Milwaukee (Dec 28, 2007)

Smoke machine will not able to find leak until it capable of push 20 psi.


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## snowish10 (Oct 29, 2010)

daff I have a 2001 f350 4.10 gear with 35'' by 12 wide tires. In the winter Im getting 13.6 in the city. Im not sure what I get in the summer since i recalibrated my speedo. 

I have a dp tuner, banks intercooler and banks turbo.


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## DAFFMOBILEWASH (Dec 9, 2006)

Truck runs at 2000rpm at 60mph and is built very light. Going to do the leak down test tonight to see if there issues. Quickly looked at the boots. One has been replaced already the rest look a little slick with oil but not too bad.


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## beanz27 (Dec 22, 2012)

Our 7.3's get 14 mpg no matter what we do if they have 4.11's, and get 12-14 pulling and 16-20 mpg with 3.73 We have no power issues.


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## goel (Nov 23, 2010)

Mine was a tired old dog last week when loaded. Just noticed thursday it was due for an oil change, which happened Friday. 

It's amazing the difference it makes, it's back to regular. 

All stock, 2k Rpms at 70 mph.

Never paid attention to mpg. It's empty so it gets filled. It's filled, then it gets emptied.


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## NBI Lawn (Oct 15, 2007)

http://minneapolis.craigslist.org/hnp/cto/3527121793.html should fix it.

Really though the 7.3 is a great engine. Should be able to yank around 5,000lbs no problem


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## DAFFMOBILEWASH (Dec 9, 2006)

Built the air intake leak down test adapter and voila.... Nothing!! Everything was tight, no air loss not even a bubble with windex on the boots. Can a good scanner read boost pressures?? How about fuel pressures ?? There has to be something wrong with it, even though it runs perfect empty.

To be honest a 6.5l pulls better. NBI Already have a 5.9 in a Ford even though it is a Louisville, best truck ever!! There is another local l7000 identicle to mine but a longer wheel base. Needs lots of love but might be the right solution for me. Buy the truck cut the frame and put a hook on load system on the back. This way it could be a flat deck, dump truck, box truck, water truck and salt truck. Perhaps there might be a new thread starting shortly.


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## rcn971 (Jan 28, 2011)

I regularly tow around 10k lbs and hardly even know that the trailer is back there with my 7.3s. I have a 99' 250 and an 01' 450


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## Holland (Aug 18, 2010)

7.3's are a great engine, ive got 3 here, one with almost 270k. Make sure your ff is good, make sure your getting plenty of fuel out of the frame mounted pump. 7.3's aren't the fastest engine, but they usually pull pretty well. A programmer will REALLY wake them up, even a small one. Found a friend of mine a used hypertech for 75 bucks and put the smallest tune in for him. Made a night and day difference and helped his mileage. Another friend has an 03 7.3 and with no programmer he could pull low 20's out of it on the highway. I installed a van turbo i had, moded his idm and he got a tuner for it awhile back, it runs out pretty good now!


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## rcn971 (Jan 28, 2011)

I installed the Edge Juice w/ Attitude as well as the Edge programmer on my 250 and see around 18 on the highway when the chip is in mileage mode.


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## tjctransport (Nov 22, 2008)

rcn971;1566254 said:


> I installed the Edge Juice w/ Attitude as well as the Edge programmer on my 250 and see around 18 on the highway when the chip is in mileage mode.


be very very careful with that programer. they are known to fry the ford computers.

there have been at least 25 threads in the past year at FTE about smoked computers after installing the edge juice with attitude junk.


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## rcn971 (Jan 28, 2011)

tjctransport;1566381 said:


> be very very careful with that programer. they are known to fry the ford computers.
> 
> there have been at least 25 threads in the past year at FTE about smoked computers after installing the edge juice with attitude junk.


Thanks for the heads up. I did mine probably at least five years ago and almost certain it was longer than that. I also did a BD trans module...forget exactly what it was called and it smoked my trans almost instantly.


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## PhilFromErie (Jun 29, 2009)

How does it start in the morning when cold?


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## Antlerart06 (Feb 28, 2011)

I have the Edge knock on wood never had a problem with it Think was 04 or 05 installed it on my 99 Did it same time the Factory Turbo went out lock up Installed a bigger one with more fines I have it in Tow mode all the time
I pull anything that will fit on my 38ft GN trailer


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## DAFFMOBILEWASH (Dec 9, 2006)

I wonder if this truck was detuned in the past. It was used as a poultry hauler down the hwy in Ontario. In fact the commecial trucks need to have speed limiters on them (105km/h). Never had it up to that speed so it is a possibility....


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## rcn971 (Jan 28, 2011)

PhilFromErie;1566737 said:


> How does it start in the morning when cold?


Like a champ every time, and I never plug it in either.


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## 02powerstroke (Nov 7, 2006)

5000lbs should be nothing to a 7.3 my 02 sees 12-16,000lbs and still rolls 70 no problem.


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## goel (Nov 23, 2010)

Hey Daff

Drove a stock 01 550 today. 60 mph at 2450 Rpms.


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## DAFFMOBILEWASH (Dec 9, 2006)

Turns out it was more driver issues rather than lack of power. Drove two other trucks and they were almost exactly like mine. My problem was trying to constantly lug the engine, by turning off the OD while pulling under 55mph and bringing up the engine RPM's the pulling power was good when towing. 

If you run the engine just like a gasser, then it will go very well. Keep the rpms in the power band 2200-2600 keep the turbo spooling and drive. By doing this it will also get better fuel mileage too !! 

Ended up selling the truck for it was going to be spare salter. With the softish winter in these parts and my wife bugging me for newer Jeep it was time to move on. Moral of the story V8 diesels need more sustained RPMs compared to the I6 diesel.


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## plowguy43 (Jan 2, 2008)

Yea hence the reason people either love the cummins or hate it. It acts like a diesel should act, power down low while the V8's from GMT/Ford act like gassers. To each their own.


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## Mark13 (Dec 3, 2006)

plowguy43;1588979 said:


> Yea hence the reason people either love the cummins or hate it. It acts like a diesel should act, power down low while the V8's from GMT/Ford act like gassers. To each their own.


Depends on the modifications and build level of the motors. There's a lot of cummins motors out there that don't run for crap under 2800rpms. In stock or mostly stock form though the V8 and the I6 motors take a little bit different technique to driving them to get the most out of them. Hammer down and let 'er eat is always effective if all else fails.


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## plowguy43 (Jan 2, 2008)

True I was mostly talking about stock vs stock. But I like your style, hammer down


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