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Does anybody know the acceptable psi discrepancies between Actual & Desired rail pressures?
I was seeing at times 1000-1200 psi differences and wasn't sure if this was OK.
Generally, this type of discrepancy puts good pressure on the skinny pedal between 2-3 gears and between 3-4 gears with 68 RFE.
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IGOTACUMMINS thanked for this post
If A\D are within a couple hundred, I believe you are good as new.
II 60HP STICKS, II 33% CP3, II S464 2ND GEN SWAP, FASS 165 TITANIUM SIGNATURE SERIES, AFE INTAKE HORN, S&B FILTER, 5" TURBO BACK, ALPHAREX HEAD LIGHTS, 38X13.5X20 RAZOR M/T, MOTO METAL RIMS, 6" LA LIFT KIT, COMPLET MM3 KIT, BUILT TRANSMISSION, 6 BOLT REDHEAD STEERING BOX
IGOTACUMMINS thanked for this post
Any idea what would cause it to be off by 1000-1200?
Again this large discrepancy only happens when getting on the gas decently hard in 2-3 and 3-4.
When I'm in 4, 5, 6 gears see pressures off by only a couple hundred
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What RPM?
Stock CP3 drops pressure after 3000rpm.
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Maybe dirty filters.
Just a thought
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Filters changed out approx 2000 miles ago.
RPMs, where I see it occur, are between 2500-2700.
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Try ohm'ing the rail plug sensor
Dodge / Ram / Cummins – 5.9 L (no start hard start diagnostic) rail pressure KOEO (Key On, Engine Off) should be 0 +/- 500psi. 6.7 L (no start hard start diagnostic) rail pressure sensor. five volts KOEO. P0191 Fuel Rail Pressure Performance; could be a bad rail pressure sensor or reporting that the rail pressure is too low.
Next culprit would potentially the FCA " fuel control actuator" that's what is dictating how much fuel is needing to be delivered to the rail
If its faulty, that could be as to why you see discrepancy in the A\D being 1000+ off from mid to WOT
To verify the FCA is good, unplug the electrical connection on the back of the CP3 which is the FCA
DO NOT GIVE THROTTLE when you start the truck as this will be giving you max rail pressure
See what the A\D is at that time and remember the numbers an shut the engine off pretty quickly
Your engine will sound completely different from being max rail pressure at idle
@Green Bay
II 60HP STICKS, II 33% CP3, II S464 2ND GEN SWAP, FASS 165 TITANIUM SIGNATURE SERIES, AFE INTAKE HORN, S&B FILTER, 5" TURBO BACK, ALPHAREX HEAD LIGHTS, 38X13.5X20 RAZOR M/T, MOTO METAL RIMS, 6" LA LIFT KIT, COMPLET MM3 KIT, BUILT TRANSMISSION, 6 BOLT REDHEAD STEERING BOX
Thanks for the info Corkey. I do have a new FCA enroute but wasn't certain this was my issue. Interesting side note concerning the FCA: Called a Cummins dealer and was told Dodge/Fiat owns proprietary rights to the FCA and Cummins could not sell it to me due to this. Parts guy at Cummins was kind enough to give me a part # and I located an OEM 1 for WAY less than Dodge dealership wanted for it.
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Corkey thanked for this post
Good deal friend! I hope this is the fix for your sake, I have a hunch it will be.
II 60HP STICKS, II 33% CP3, II S464 2ND GEN SWAP, FASS 165 TITANIUM SIGNATURE SERIES, AFE INTAKE HORN, S&B FILTER, 5" TURBO BACK, ALPHAREX HEAD LIGHTS, 38X13.5X20 RAZOR M/T, MOTO METAL RIMS, 6" LA LIFT KIT, COMPLET MM3 KIT, BUILT TRANSMISSION, 6 BOLT REDHEAD STEERING BOX
Can you share the part number and year of your truck?Originally Posted by Green Bay
2015 / RAM / 2500 CTD-68RFE-4wd / 3.42 / stock tire size / Silver / Bighorn
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