My 2000 7.3 2wd 148K has started lossing power and rough idle whenever i run it the least bit hard. If i drive like little old lady it does ok.
After i punch it it rattles shakes loss power max speed steady decreasing
until i pull over and let it catch up (5 minutes but getting longer) or just shut it down for a while. Sometimes it will die on it own very hard to restart without the wait. It's seems to be getting worst.
I replaced it with ebay CPS engine won't smooth out, runs very rough.
I replaced the CPS with one from AutoZone and the truck won't start. Put old one back and it starts.
Exchanged for another autozone CPS and truck won't start again.
Auto zone appears to have the wrong part number or poor QC.
Only the old cps makes the truck cranks and run smooth.
4 different CPS and 3 different effects. (both autozone won't start).

IF the truck sits overnight it cranks and runs great until you try to pass someone.
I do hear the fuel pump running now, sounds like it running in a strain.
Replaced air and fuel filters.
Don't know if it always did this or i'm just hearing it because i looking for problems.
Autozone scanned it and found no codes.
What next?

 

Just a guess at this point but when was the last time you changed the fuel filter and/or checked for water in the separator?

 

The symptoms are the exact ones that would go with fuel beginning to gell, which causes fuel starvation. If you fuel filter is good, I think you are on the right track with the fuel pump.

There is a screen on the fuel pickup in the fuel tank and also one inside the fuel pump. If you got a tank of really bad fuel, either one of these screens could be plugged as well, causing the same symptoms.

 

Not suprised about the Autozone CPS. I found out the same way. Autozone and Carquest both sale the wrong one or bad one not sure but I know they don't work. The other guys here have it right it sound like it's not getting enough fuel. Start with the filter and work your way up the dollar tree from there.

 

that sounds like fuel pump systoms to me as well. i think i remember hearing the CPS's that auto zone sells is the one for OBS trucks and does not work in the powerstrokes

 

Thanks guys, i just filled up to the neck, perfect time to drop the tank.
New filter was first when it started acting up.
Where in the pump is the screen?
Any pic online?

Guys if you have a CPS in the glove box, best to try it at home and put the one one in the glove box. Then you KNOW you have a spare.
10 minutes can save you much more time and money.
Besides once you have done it the first time, you can do it in the dark on the side of the road if needed.
I Thought i had a spare! , Really glad i didn't need it to get home.

IF you have the autozone cps #2159, take it back if you can.

 

I wish someone would have told me about the autozone CPS before I broke down on the side of the road. Took me 45 min to change it 30 min trying to find the bolt I dropped in the grass at 10:00pm. Back to your problem, I would check my fuel pump before I dropped my tank. It's located on the driver's side frame rail about where your door is at. If it's working right you should be able to hear it humming when you turn the the key before starting. Listen for it and feel it, it should not get overly hot if it's good. Is there a good amount of pressure at the fuel bowl? The fuel system is pressurized after the pump and you should have a good flow if you open the purge valve on your fuel bowl with the key on. It may still be the screen in your tank, but usually when I've had a problem with those is if I got a really bad tank of fuel, the truck been sitting for a long time with out being run, high miles, or years.

 

[QUOTE=hott-rodd]Thanks guys, i just filled up to the neck, perfect time to drop the tank.
New filter was first when it started acting up.
Where in the pump is the screen?
Any pic online?
QUOTE]
The screen in inside the pump on the suction (rear) side of the pump. The pumps are sealed units, and have a check valve so you can't clear them by blowing them out from the pressure side. That's where my pickup tends to gel first, and I have cleared the wax buildup in the pump screen by applying compressed air to to the suction side.
Hope this helps.

 

ok two things . whats a cps? and how long does the fuel pump normaly run when key is switched on?

 

I also had the problem with Autozone. I bought the first one, and it didnt work at all, and they gave me a new one that actually worked, same part number and everything, but now the truck is starting to run erratically again, good thing it has a 30 day money back guarantee!

 

CPS stands for cam position sensor.
My fuel pump runs for 10-15 seconds when the key is turned on.

 

If you are suspecting the fuel is gelling up, why don't you add a bottle of treatment first? see what happens. I usually add 16oz of DK grey bottle in the winter just to prevent this, even though the pumps are switching to winter fuel, I don't want to take the chance. Plus it helps clean the system out as well.

 

It's not fuel get it's 60 degree.
Sometime i can go 20 miles before problems.

I do believe it's a fuel problem.
The pump really sound like it's running in a strain.

action plan:
1. blow thru pump from tank side.
2. drain fuel and drop tank.
3. check in-tank screen
4. either way get a new cps installed that works. (maybe two, must have a working spare)

Thanks guys, hopefully i'll get off in time to work on it today.

 

Thanks Clux
It's fixed!
Atleast for now.
I opened the water separter and pulled the fuel line for the tank side of pump.
apply 120 psi air to back of pump. it makes a nice mess.
Apply 120 psi to fuel line back to tank. This too makes a mess if the tank is full.
There was definitely a blockage somewhere, I can hardly hear the pump run now.
Tested it like a 16 yr old in dads corvette, runs better than ever.
I don't know if the problem will return but if it does i won't have a full tank of diesel and 40 degree nights to start with.
new cps works great too.

 

update,
problem came back after 150 miles,
I gave it another 120 psi shot and got another 100 or so,
finally got the tank almost empty.
pulled the tank expecting a clogged pickup.
It was not the pickup that was clogged, there are two towel filters
INSIDE the white pick-up return housing. Both clogged with some grey mud
looking gunk. I did the in-tank mod with a slight twist , reused the black pickup foot. I'm adding external filter tomorrow.