99 power stroke low on power :-(

xjtrailrider

Active Member
Joined
Dec 15, 2012
So I towed my XJ to Harlan last week for the Cherokee Crawl and I was less than impressed with the performance of my "new to me" 99 PS with 85k on it. It was a struggle to maintain 65mph on the highway and I got 10.5 mpg (hand calculated).

I have done the following;
Checked all boost connections/clamps
Checked the turbo for wear and end/up/down play
Checked for codes, none, no SES light or flashing OD light on stalk

Whats next?
 
Fuel filter, aid filter, and does it have a cat converter?
 
must be all stock
install
Power Hungry Performance or Swamp Diesel for a tuner
& a KC1 design turner display ( b/c they are bad A$$)
napa 6637 air filter mod
& new 4" turbo back exhaust
& you will be happy with the power of the truck ( for a little while LOL ) for around $1150
 
Last edited:
dkrajcovic said:
must be all stock
install
Power Hungry Performance or Swamp Diesel for a tuner
& a KC1 design turner display ( b/c they are bad A$$)
napa 6637 air filter mod
& new 4" turbo back exhaust
& you will be happy with the power of the truck ( for a little while LOL ) for around $1150
Click to expand...

Yes its all stock with the exception of the RiffRaff 6637 filter kit. It doesn't have power, something is wrong with it. I need to address the issues before throwing parts at it.

GotWood said:
Fuel filter, aid filter, and does it have a cat converter?
Click to expand...

New WIX fuel filter, RiffRaff 6637 filter kit, no on the cat converter
 
what is fuel presser , boost ??

i still think all is good just need to add some power
 
Make sure your EBPV is not stuck half open.

Useless to upgrade the air filter with out upgrading the exhaust.

Change your fuel filter as said.

Get a tuner.

Mileage sucks on a 7.3 anyway. Get used to it or find a veggie source & start cooking oil for fuel.
 
frankenyoter said:
On my OBS if the tuner is off the truck feels like something is bad wrong.
Click to expand...

This.
My 99 7.3 auto feels like an absolute turd on my stock setting. I keep it on a tow setting most of the time and it feels like I thought it "would have".

There are vendors on here who offer whatever intake, exhaust and tuning items you need. Take a look in the vendor specials forum...

It won't hurt to replace the fuel filter as a matter of fact. You can't "see" when they're bad all the time.
 
If your truly convinced it's low on power some basic diagnosis as these guys have mentioned will go a long way! I think ebv stuck and up-pipe leaks are the main issues we see in the shop causing low power on a regular basis.
 
My 02 6spd 7.3 was a turd in stock form. It pulled just fine but it didn't do it quickly or get the best mileage, but it did the job. 421 from Duffield, VA to Pennington Gap, VA on the way to Harlan was always my test for upgrades done to the truck. It was a turd and 4th gear to the floor bone stock to make that first pull up from Duffield. After BHAF, Wicked Wheel, PHP Tuner set on 65hp/Moderate Tow, 4" Exhaust no muffler it would do it all day in 5th and carry 55-60mph, but I would regularly run it 1/2 throttle in 4th to keep the EGT's down, they were never an issue but I would do it just to be on the cautious side. One time that hill mysteriously moved to Mexico and was run much faster, but I don't like Mexico.
 
While your at it check to see that the turbo halfs are still bolted together tight.Sounds dumb but it happened to my 01.
 
1-tonmudder said:
While your at it check to see that the turbo halfs are still bolted together tight.Sounds dumb but it happened to my 01.
Click to expand...
This happened to mine too.
 
Guys, I should have mentioned that I have a new WIX fuel filter, the turbo was checked and is good, all boost lines were tightened. I'm getting 10mpg in town empty. Its got something wrong but it runs smooth and pulls good empty. Hook up a trailer and it rolls over and plays dead. This horse doesn't want to pull LOL!
 
The three gauges every turbo diesel needs that they don't usually come with are: boost, EGT, and fuel pressure. From those, you can narrow down almost anything.
 
Does it stumble on start & smoke a little? Especially if it sits a week or so?
 
2 Question to the diesel guys on here:

Will the injector nozzles being worn cause mileage to go to crap like this?

What is the normal injector life span on a 99-04 7.3?
 
Jeff B said:
2 Question to the diesel guys on here:

Will the injector nozzles being worn cause mileage to go to crap like this?

What is the normal injector life span on a 99-04 7.3?
Click to expand...
Usually not a decrease that significant and misfires or all out failures (solenoids, tip failure etc) are more common. Due to the design of the fuel/oil system performance and mileage may decrease over the years. I've replaced these injectors at 100k and on pretty commonly. Typically a poor seal at the pintle or or nozzle issues present themselves in blue smoke at idle prior to a loss of mileage being present.
 

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mysterync said:
Stretch that was just the loose nut behind the wheel....
Still have your flashlight....
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Hahaha. Consider the MagLite a donation to the shop supplies. :lol: I totally forgot about it and have another one now. But u rite on that loose nut. Its been tightened down, but not much consider Robbie owns the truck now. 235k and beaten on a daily basis overloaded with construction supplies.
 
Jeff B said:
2 Question to the diesel guys on here:

Will the injector nozzles being worn cause mileage to go to crap like this?

What is the normal injector life span on a 99-04 7.3?
Click to expand...

i put 210K on my 00 f550 work truck but i changed the oil & changed the oil in the hpop tank & fuel & air filters ever 4k miles
 
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