I put a HPOP gauge on my truck today.

[hayjayhorses]

I set up a hydraulic gauge to monitor my HPOP pressure, on my ’00 F550, 4R100, 4.88, 4” turbo back, 290,xxx miles, stock tune. I made up a hydraulic line with an “O” Boss fitting on one end and the other end I put a 5000 psi liquid filled hydraulic gauge. I put the line into the 3rd port back on the (LH) drivers side head. I have it set up on the cowl so I can see it as I drive.

I did this because this truck just seems to have no guts when you are heavy into the throttle above 2200 rpm and the SES light will flash at this time also.

Here is what I got for reading, pulling about 2500# worth of trailer around town.

Idle 4-500 psi

Light throttle above 1700rpm 2200-2500 psi

Heavy throttle its at 1200-1400psi from 1500rpm to 2600rpm and will then the psi will climb to 2000ish up to 3000rpm

If I let off the gas and hold about ¼ throttle the HPOP pressure will go to 2500psi and it will stay there until I step on it again.

I could not get the HPOP above 2700psi and yes my oil is full.

Any suggestion? Time for an Adrenaline pump?

I shimmed all the injector magnet plates 0.002” about 30K miles ago. I have some reman stock 90cc single shots I am going to put in this truck as soon as I get my TS chip back (I wish I knew of Bill and Co. last year) with single shot tunes.

[907DAVE]

You might have a HPO leak some where, how are your injector o-rings?

Does the oil reservoir ever drain down after parked for a long time?

[hayjayhorses]

yes the HPOP reservoir will drain down after a few days of sitting I have checked it by unscrewing the oil pressure switch on the top of the reservoir an dropping a screw driver down there, and there is like an 1/8" of oil on the end.

But even with the oil reservoir empty the truck with fire right up and run, it just take 6 to 8 seconds for the oil pressure gauge to jump up to normal.

I have not pulled the injectors yet, I want to drop in the single shots when I get the chip back so I don't have a rough idle issue.

I have seen ripped/deteriorated O rings on a lot of OBS truck not really on SD

[907DAVE]

Sounds like you may have an upper injector o-ring(s) that are bad.

[hayjayhorses]

I will pull my injectors tomarrow and see. thanks

do know how rough the idle is, using single shots in a SD with no tuneing?

[907DAVE]

Its rough.......like having a lope tune without the tune.

Of course that was with my 238/100% hybrids on split tuning, so I am not sure how bad it will be with your injectors.