jurish

I just installed a set of gauges to watch my lift pressure (post filter) and rail pressure. At idle I have 15PSI lift and 7000psi rail. if I am cruising and bump it to HOT and ease into the throttle, rail pressure drops to 5k before trying to climb back up. Once I get to 80mph and start winding out, the truck starts bucking like a bronco, and I can see my rail pressure jumping all over the place between 10k and 17k. Could my CP3 be shot? Maybe the FCA? Lift pressure during the bucking is around 12PSI.

J-man

Set the low boost fueling adjustment to 1 and see if it does the same.

jurish

Yup.. Same deal. I really suspect my CP3. When it's bucking, lift pressure never dips below 10PSI. Rail pressure bounces wildly between 10-15Kpsi.

I need to find somebody in the dallas area that has an edge hot juice that I can swap in and do a couple runs. That way I can eliminate the edge as the problem.

chadder1313

Hmm before id count out the CP3 id look at the Edge also. I run Smarty TST on 9 which is a 230 horse tune and my truck takes it all day.

cincydiesel

I would guess that your killing your LP. I can drain mine on an open road on level 4 let alone on 6. Is there any popping noise during the run? I dont think you have enough fueling to drain the rail

jurish

Its funny, on level 0 when I hit WOT there is pinging / clacking. I can't say that that is happening on lev6. As soon as I start getting close to WOT it starts surging bucking like the extra fuel is turning on and off.

Let me ask this question, At what pressure do you call the rail "drained"? The truck idles at 6-7k...

CamperAndy

The rail pressure can go as high as the mid 20's at WOT anything much less then 20k will have fuel shortage issues.

It could also be defueling due to EGT or one of the other protection modes. Are you sure it is not that?

cincydiesel

I dont think you have enough fueling mods to completely drain the rail.. My guess the surge you feel is a combination of the stock T/C and the stock LP pump not being able to keep up with the fueling request

jurish

Nope. I turn all the defueling off.

jurish

The kicker is that this setup "used" to work good till I had water in the fuel.

The lowest I have seen LP is 5psi. Is that too low?

CamperAndy

Never hurts to have info like that at the start of a thread. So yes you could have CP3, FCA or injector damage that causes the problem you are seeing.

jurish

Yup, dumb me, should stuck that in there, but the whole fuel system has been replaced except the CP3.