I have an 01 ext cab short bed 7.3 with a 6 spd, it has 284k miles on it ts chip tuned by tyrant diesel. The other day i was messing around on my way home from work and hooked a snapon scanner up to it to read my hpop pressure to see how the pump was doing. With my chip in economy i cant remember hp i think its 75 it runs around 2900 psi at WOT and with my chip in 140hp around 3500 psi. The more i played i noticed that just driving down the road 65mph not standing on it that when i come to a hill the pump will build more pressure in my economy tune than in 140hp tune pulling the same hill. I would think that it would be the opposite way around, it would build more pressure in 140hp tune than in economy. Also the truck dosent hardly smoke. What do ya'll think?

 

The 140tune is asking for more Pulse Width and the pump can't keep up with the demand....so the pressure starts to fall off.

 

To add to what Dan posted, You'll see this better reflected by viewing Injector control pressure and injector control press duty cycle at the same time. In the higher HP settings the duty cycle will increase as it tried to keep up with the demand. Duty cycle will continue to go up until it hits around 65% and trips the check engine light. All normal on a chipped truck with stock injectors & stock pump.

 

It's not that simple. There is no oil demand just cruising down the road. The performance tune might have the ICP dialed lower at that RPM in that tune for a specific reason. Remember - one is for max torque, and the other is for max MPG... and they behave differently at different RPMs, as well as WOT.

 

I didn't think you could even get 3500pis out of a stock pump? Anything over 3000psi is asking a lot for the stock HPOP.

 

I think DP holds the line @ 3200 from what I've seen.

 

After rereading the OP's post I have to say I could have done a better job in my response - I did not answer his question. Basically Bigbubba87 was asking why his Tow tune is showing higher ICP than the 140 hp tune and Rich answered it. It depends on what the program is asking for.

I see similar results in my tow tune as well. The graph shows the ICP maintaining 3,000 psi for one of my tow tunes while pulling our 10,000lb camper.



In my higher HP daily driver setting I also see a lower ICP reading at the same gear & rpm's as the tow tune.




Same situation in this tune as well. But note in this tune my HPOP is not able to maintain the ICP and starts to drop off. Not to the point of tripping the check engine light, but probably would have if I kept the pedal to the floor. But my speedo was already acting like a windshield wiper......



Finally here is an example of the situation I spoke about in my first post - it is common in the higher HP programs that the HPOP can not keep up with demand and the ICP Duty Cycle will continue to increase to try a meet the demand from the program.



As Bonanza pointed out - 3,500 psi is a very high ICP for the 7.3L. Others that have run higher ICP programs and have done used oil analysis reports have show the oil to shear the viscosity much quicker than average. So if you are running a high ICP program than make sure you change your oil sooner or do a used oil analysis to see what your setup is doing.

If you want to test your HPOP Swamps Diesel has a good write up on this.

http://www.swampsdiesel.com/site/faqs.html

Click on "how to check if my 7.3L HPOP is good"

 

I've seen that last graph about a gabillion times. look at the FIPW with it.

 

That graph was from an FTE'r Justin about 5 or 6 years ago IIRC......I'll have to boot up the old dinosaur laptop and see if I still have the raw data.

The title I put on the photo in photobucket was "Justin 03PSD stock inj, DP tuner, stock HPOP"

 

Wow, I actually still had the file and it only took 15 minutes for the old dinosaur laptop to boot up! FIPW - she's up there......North of 4.5 in some spots..........almost hit a 5'er.......

 

I will test it going off of swamps write up and see what my pressures show, after thinking about it and what you guys said it makes sense why the pressure is lower in 140 than in the economy tune