07 Cummins with a mind of it own!

timbo24

timbo24

Casper
Joined
Oct 13, 2009
Messages
20
I have got a 07 cummins with twin turbos, twin cp3's, airdog 160, electric water pump, built 48re, 120hp tips. I am having problem with the rail pressure surging on the truck. when you take off from the light it starts surging after 1/4 of throttle. Rail pressure fluctuates 5,000 to 10,000 psi and will not quit until you let off. The rail pressure at idle is good and cranks the first bump. Sent the cp3 pumps off to get tested and came back perfect. I also sent the cp3 controller back to ppe and it tested good. Wtf could it be an injector?
 
very, very possible it's a defective fuel psi sensor. Be careful cause mine did that a few times and went to wide open throttle on it's own.
 
timbo24 said:
Are you talking about sensor on the rail or injector?
Click to expand...

yeah, the sensor on the rail. It will cause spiking like you mention. Get a hold of "Snedge" here at the forum. He's a Cummins dealer and can hook you up with a new one if that's what you need.

Were the FCA's checked when you had the pumps checked ?
 
I sent both pumps to shane at motorsport diesel because he built my dodge pump. The dodge pump flowed 299 lph and the durmax flowed 208 lph. I am assuming that he checked them. I never had this problem till i put twin cp3's on. Run great for 2 weeks and then the problems started. Truck would just shut off. Fass was not returning any fuel to tank or holding supply pressure so i bought a airdog. Now if you get on it from a dead stop it runs the lift pump dry, and now it surging.
 
I also unplugged each cp3 by itself while the truck was running to see what the rp did. When I unplugged each one of them the rp went to 30,000 both times.
 
sounds like you might have the lines on the pump connected backwards..... it's easy to do. Even if it is, it will still pull fuel through enough to run the truck... just not well. Shane is really good about his stuff so, I'm sure he would have checked the FCA's.

edit: nothing wrong with the FCA's then.
 
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I thought the same thing at first, but I have checked them a million times. I drove the truck last night 60 miles when i started out it was just a mild jump in rp. When it was surging I could turn the mp8 up and hammer on it and it would pull like hell and the rp would hold 30,000 steady.
 
Now just easing around town it surges 5,000 to 10,000 psi and the mp8 does not affect it.
 
ok, make sure you have the sensor plugs plugged in, in this order on the RPS....

RP gauge, MP-8, oem harness. If they aren't, that can cause issues too.

If you have a friend you can borrow a rail psi sensor from, that's one way to check it. I think they're in the $150 range if you buy one.

What did Shane say about your issue ?
 
Let me clarify surge. It goes for 20,000 to 15,000 and back to 20,000. Its not just at 20k. It does it at all pressures above 10k.
 
He told me that i probably had other issues such as an injector. So i was going to pull them and send them to exergy.
 
Not sure what to tell you man, I think I'd look into the RPS before going through the trouble of pulling the injectors. What programmer are you using ? Is your wastegate set right ?
 
I am using smarty tnt. Just checked the order on the fuel rail and it the same order you gave to me. I have the same turbo set up that i have with my mod cp3 set up. Wastegate turned off with quad boost fooler. What i am wondering is if supply pressure to the cp3's is too low. I mean i took a pump that is used to run at 15-18psi and running it at 10psi because ppe says 10psi. And on top of that it mod and flows almost 100 more lph. So i am gonna turn the airdog up and see how it acts. If there is no change I will change rps and go from there.
 
What pressure is lift pump set at? I know me ppe duals dont like anything over 20 psi
 
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