CrashCade

Well tonight for the first time I monitored my Inj pressure on both my commander and Outlook to see if they read any different. Well holy cow, the Commander I do believe is correct. I watch it and I can stay at 24k-25kpsi until I hammer down anywhere from 1800-3000rpms and I watch it drop to as low as 14k. I thought something was causing some sort of defueling before I saw this tonight. It looks like the commander sees something totally different than what the outlook sees. Which I guess is understandable seems how the outlook gets its info from the OBDII port. I was seeing around 16k-18k at cruise speeds on my Outlook and when I floored the go pedal I would see about 23k. So I always figured I was ok.

Now I am left scratching my head and wondering if I need to change my cp3 to something bigger or add another one, and just step up to twins. How bad is it to drain the pressure like that? Does it cause problems or just loss of power? I just want to make sure I am going to be ok and not damage anything if I continue to run it like that for a couple of months...

WUnderwood

yes, if your rail pressure drops too much, you arent getting enough pressure to the injectors, thus not getting 100% performance out of them

get a bigger CP3 or twin cp3s, or turn your boxes down so they don't drain the rail so much

you might need some dyno time to see what and where you drain the rail

just my opinion

dodgezilla04

the outlook at obd2 port may be receiving what the ecm is commanding the pressure to be, not the actual pressure with all the mods and fuel demand.

cquestad

Below 25....your not making peak power anymore...

What injectors are you running?

omaharam

Yes you are lacking power, but, at 14k I believe you are still providing enough fuel to cool and lubricate the cp3. So it shouldn't actually hurt anything - other than performance.

CrashCade

I have the II modded CP3 and II extrude 3 flows.

cquestad

I hate to say ouch...but ouch.

Turn down the elctronics till you maintain a rail pressure of at least 23k...and that will be your peak power.

If that number is not enough...blame your pump or injectors or both.

CrashCade

So, it is possible to maintain that type of rail pressure right? I just need the supporting CP3 or CP3s?

cquestad

Yes...you need enough pump(s) and injectors that will hold pressure.

There are some injectors that will not maintain rail pressure with any pump.

How big are your 3 Flows? You may want to consult abc4yew via PM.

CrashCade

I was told they are about 90hp injectors. I am hoping they are not the cause of this, but they are the cheaper alternative to doing a dual pump setup. I will check into that. Thank You.

cquestad

I have watched the 90's....drain a few rails in my day.

jrussell

Do you have the "30% more flow than stock" pump? What does II have to say about it?

They advertise their 90hp sticks "work best with II’s Modified CP3 fuel pump, but will also work with the stock CP3 fuel pump". I would want to know why that doesn't seem to be the case.

CrashCade

I am go throw and analog gauge on it and see what I can figure out. I am pretty sure from the way it feels when I see the pressure drop off on the commander that it is porbably right, but before I ask II about it I want to make sure it is not an electronic glitch.

king d

i had the exact same set up and it worked well enough to get into the 11s with a touch of n20 then i added another stage 2 ii pump and now i have stooooooooopid rail pressure when ever i want it...

jrussell

Please keep us updated...