Low HPOP pressure

05 Stroker · Dec 1, 2013

Lately I've been noticing my hpop isn't reaching full pressure instantly when going WOT.

It starts fine, but I did notice a slight miss lately. I'm pretty sure the miss is injector related, because I've pulled codes for injector 6 and 8 balance.

My truck is an 06 with 225/100 injectors. It never had an issue reaching 4000 psi wot before, now it has a delay, it'll hang around 1500 psi then shoot to 4000. Today I took it out and it wouldn't even hit 4000 it just hangs at 1500.

Is it most likely going bad?

05 Stroker · Dec 3, 2013

Bump.. I'm trying to research the topic more. It seems like when the hpop goes, you get low pressure across the board, I would think a leaky STC fitting would have some similar results.

What would cause a lag in the pressure building? It's inconsistent, but when it does pump up it shoots right to 4000 psi.

I also checked the oil, the level is good, but this oil looks pretty well cooked, I'm going to change it this weekend for some good stuff.

fbilly420 · Dec 3, 2013

I would check for leaks before replacing the pump for sure.

05 Stroker · Dec 3, 2013

What's a good way to check for leaks?

webb06 · Dec 3, 2013

Does the truck run fine or is it lacking power when it isn't building 4000 psi? Not many people monitor icp on a daily basis so if its running fine I'd let it be until something more serious shows up.

Easiest way to test for a high pressure leak is make a fitting to replace the icp sensor. Manually close the ipr valve using an ipr wiring pigtail connected to a battery. Then apply shop air pressure to the fitting and listen for leaks.

STC fitting, dummy plugs, standpipes, oil rail nipple oring, very top of injector oring, or rear pump seal are the main issues we've personally seen

05 Stroker · Dec 4, 2013

I have an hpop gauge on my pillar, and noticed the truck wasn't fueling hard at wide open so that's the first place I checked.

The odd part is how it happens.. At first it would just be a slight delay before I would hit full hpop pressure, I thought maybe that's just how my street tune was written, it was like traction control lol, it actually made the truck more drivable so it made sense.

But over time I'm noticing the delay getting longer and longer. The last time I drove it, I was pulling out into the road, rolled on the throttle until wot, and the pressure stayed at 1500. I drove to a private road to verify the problem, rolled into the throttle hit 4000 psi right away, and was blowing the tires off and bouncing off of the limiter. So I turned around, tried to roll into it gently until wot in 4x4 to better observe what happens and it just wouldn't build pressure..

I know leaks in the STC fitting, dummy plugs, and stand pipes tend to cause issues with hot starts, but I'm getting 500 psi every time I crank it up, it's only under wot I'm having the issue.

Is there a chance that I have a sensor going bad? And it's not commanding full pressure?

I know it's not just the gauge reading incorrectly because the truck has about half power at wot when I don't have full pressure.

webb06 · Dec 4, 2013

I guess you could swap icp sensors out with a known working one. Or unplug it and try going wot and see how it responds, you won't be able to monitor the pressure but you will be able to tell if its at full power.

05 Stroker · Dec 4, 2013

Doesn't the IPR have the control over the oil pressure?

Both sensors are pretty pricey just to "check and see"

Would I be getting codes if either of these have gone bad?

webb06 · Dec 4, 2013

05 Stroker said:
Doesn't the IPR have the control over the oil pressure?

Both sensors are pretty pricey just to "check and see"

Would I be getting codes if either of these have gone bad?

Ipr controls the pressure but the icp sensor gives out the reading. Each sensor is over $200 so I didn't know if you a buddy with a 6.0 that you could swap with to check.

I don't think you would see any codes.

05 Stroker · Dec 4, 2013

Nope, I'm the "gonna prove them all wrong" guy in my group of friends, the rest of my friends drive duramaxes and cummins lol. But I love my 6.0 and nothing will change that.

I think my best bet for now is see what happens if I unplug my ICP sensor.