Not producing rail pressure

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bignazty

New member
I have 06 CR. with 10mm stroke exergy 100% over inj. My truck is not holding rail pressure the way it should some people have told me that it is the relief valve of the rail. I tend to think it is the rail sensor. I have a VP tune setting on my CSP5 switch and when I turn it over to it, it will not command the rail pressure that I need to make the tune work. also on tune #1 at WOTE I get up to around 30 PSI boost and it just stop. It fell's like it did back when I had a stock CP3 and was running out of fuel on my rail. buy with the stoker pump I should not be running out of rail pressure at this time. I wondering if the sensor is not communicating with the computer or what? How do you check the rail sensor and see if it is bad or what. been beating my self up on this one. :nail:
 
Data log the stock tune and see if it reads what is commanded. The pump should maintain with stock tuning. If it still doesn't, you have a problem and you can try a rail plug to determine if the relief valve is good or not, those are cheap compared to a relief valve.
 
Ok, so the truck runs and drive good it just when go to WOTE, it falls flat on its face. that is on tune #1. When I turn it up to setting 4 it produce a lot better at WOTE. But no where near what It need to. I really don't want to plug it off. I still drive the truck a lot and pull with it alittle bit.
 
synonymous with butt holes, everybody has an opinion and different luck with the kind of toilet paper they use ;)
 
I put a new plug in it and still has the same problem. where to go from here? is it the pump... got a 10mm stroker exergy less than 5k miles on it.
 
So I'm confused once I've read this again... is the truck commanding enough rail pressure and it won't hold it? Or is it not commanding enough?
 
Typically the Relief valves dont give problems on 5.9s unless it is truely bad. Look at desired vs actual at WOT. If its commanding the pressure and not making it, you either have a weak pump, an injector returning too much fuel (typically gives a hard start) a faulty FCA or a bad PRV.
 
if rail sensor is disconnected the truck will not start. any codes? did you plug it in the correct way? you can plug it in either way....
 
The truck runs and drives. Drives good while easy into the throttle and not really pushing it. It seem to get up to 21k-22k rail and stops there. While I am commanding 25k on the rail. On tune one at WOT it get up to 21k on rail and 30ish psi boost and falls flat on it face, With plenty of rpm to go. tune 5 witch is my race tune it get around to 21-22k on rail and it struggles to keep up with the injectors at WOT. inject are 100% over and CP3 is 10mm stroker exergy. I feel like that the pump should keep up with the inject's. It seems no matter what tune I have it on 21k-22k psi and it tops out there no matter what I am commanding. As far as codes go p0541,p0073,p0107. but I deleted my grid heater.
 
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you need fuel to make boost. that rail pressure is still low @ WOT.

you really need to find a good scan tool or someone with EFI LIVE.... then look At FCA current, as said above, commanded should MATCH actual RP. Either you are loosing RP, or not making it.

Any smoke?
how many miles on the sticks? could be several with high return rates guys???

the fact that you have a code for ambient air temp AND MAP sensor low voltage low bothers me. this affects fueling in the ECU.

Maybe someone could shine on that subject better than me....
 
SixOhh said:
you need fuel to make boost. that rail pressure is still low @ WOT.

you really need to find a good scan tool or someone with EFI LIVE.... then look At FCA current, as said above, commanded should MATCH actual RP. Either you are loosing RP, or not making it.

Any smoke?
how many miles on the sticks? could be several with high return rates guys???

the fact that you have a code for ambient air temp AND MAP sensor low voltage low bothers me. this affects fueling in the ECU.

Maybe someone could shine on that subject better than me....
Click to expand...
Sounds like they may not be plugged in?


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I do have a guy with efi live, this is how I know what I am commanding. stick are new less that 5k miles and same for the pump put both on at the same time. I took my truck down to the local auto parts store and had them put the scan tool on it and those where the codes. I tried to erase the codes and the scan tool would not erase them. not for sure if that means any thing. Googled code and said to pull it out and try cleaning it. I am going to do that next. I do have a boost fooler installed to. Is there a way to check and see if it is bad. I do not want to just throw money at it and guess would like to narrow it down.
 
just get rid of the boost fooler.

what tuning are you running? most modern tuning does not require a boost fooler.

as far as clearing codes go, was the engine off with the key in the run position?

find that guy with EFI and see what your FCA is telling you!!!!
 
Got rid of the boost fooler, in the process of doing it I seen the intake manifold gasket had blown out the side. You are right my tuning dose not require the boost fooler. Yes the truck was off with the key in the on position. I replaced the manifold gasket. In the process took the MAP sensor out and cleaned it and put it back in. IF that dose not work I am going to purchase a New one and go from there. My tuning guy sent me some new tunes going to try the new tune out this AM Data log it and send it to him and see what it say's. I will find out what the FCA says after the LOG.
 
What duration does your race tune run? I know my 10.6mm stroker pump wouldnt keep up with 125s at 2700us, and 100% overs are quote a bit larger...

If everything is working properly, you may need dual pumps.

First thing you need to do is post a log though. Needs to show, timing, duration, fuel qty, desired RP, and actual RP.
 
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