Just to be curious, what's the fuel pressure in heads under load? Those injectors have got to tax a lift pump pretty hard.

Fuel pressure is not an issue as I am pushing close to 140 gph @ 60 psi through the heads at all times.:yikes2:

That's a bunch

You are right! It uses a 5/8 pickup tube to the pump/filters then 1/2 all the way to the engine where it splits to 3/8 to feed the rear of each head.

Well after taking yet another look at the PW map it appears I took close to .3 MS away from my Idle range..........I added that back and might give it another try tonight.

I just cannot wrap my head around what that actually did to my ICP/IPR%.:hmmm:

This damn laptop. I had 3 paragraphs written and it thought that it needed to do an automatic "go back to previous page" action...... I need another piece of duct tape over the touchpad. I thought that these things were only supposed to work with a finger touch; not shadows, shirt sleeves, moving air, etc.

Anyway, the condensed version goes like this.....

The injectors do have a mechanical threshold that doesn't allow them to inject any fuel at .4-.5 ms. of commanded pulse width. Judging by the map you posted, you might be pretty close to that and you might be losing some efficiency.

What is your actual IPR DC % while all of this is going on. I suspect that you may be at about the minimum 5% duty cycle....but with dual IPRs you SHOULD be able to dump ICP at 5% so that is a moot point.


Dave, I'm uncertain of what is going on. You absolutely NEED an emulator so I will send you mine when I get to Georgia so you can get all of your issues fixed quickly instead of doing the tune-test-repeat cycle over and over (since I know that that portion of the tuning is the most frustrating because it takes 10 minutes per tune to do it).

By the way, the XP disk should be arriving one of these days too. I sent it yesterday.

Funny because I posted this morning but I guess it didn't stick.:shrug:

At idle Duty% seems to float around 7%-8%, so I dont know if that is causing me any issues.

Cody, is the .4-.5 ms limit on the injectors because of the delay in the PCM to IDM communication then the actual mechanical delay in the injector itself?

What is even more interesting (to me) is that while cruising the PW is typically around 1ms @ +/- 1200psi, so in reality is the injector is actually on injecting fuel for .5ms.

Well what I did was return the PW in the Idle range to where it was before, then use the MFD map to pull additional fuel from the specific ranges I was experiencing the smoke. Seems to work very well now, very minimal smoke, much more stable idle, and the Cruise Control is MUCH happier now.:woot:

Still needs some more tweeking on but I am inching closer. Now if I could just get the Converter Duty% figured out.:D

Thanks again.:thumbs up yellow:

Well its back to the drawing board..........

With a few more minor adjustments truck was behaving perfect. Almost no smoke under 3/4 throttle, shifting was good, power was good......... until today.

I was attempting to cross the highway which was very busy, my turn came so I stabbed the pedal and nothing. Ohhhh crap, luckily I made it across unscathed but definitely not acceptable. I did some experimenting on my ride home and it was just in the sub 1500 range that there was no power, ease into it and you would never know anything was wrong.

I am unsure what I took too much away from, but I think it is the MFD map..

Maybe there is no cure for these injectors, but I will keep on trying.

Can you please explain exactly how the ICP is increasing when you decrease PW. I just cannot see how it is happening, even though I know (well think) it is.

Also, what happens in the ICP map when MFD is higher than 47 mg/ Stroke.

Ok......now I am just going crazy. One program has a limit of 37 and another has it up to 70...............:hmmm:

I am in over my head.:doh: