Whiplash25
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- May 11, 2021
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Hey all, This might be my first post on here and it’s gonna be a long one.
Anywho, I am working thru an issue with fuel pressure fluctuations at idle and under load. The truck is a 21 6.7 SO with the 68RFE, Ez Lynk with CCS tuning, Black Market Performance Cat filters front and rear, and a Banks CAI, with 24k miles, no warranty.
So I noticed the issue about a week ago after exiting the freeway and sitting at a red light. Truck was acting almost like it had a random misfire. I checked codes and got U0002 which came back as pretty much nothing. Deleted code and it never came back. No CEL no issues until this past weekend. The wife and I we’re coming back from the store and came to a stop sign. Same issue of a rough idle, no code this time. Got home stopped in the driveway, same issue. Moved the shifter to park, issue stopped intermittently, then started the rough idle but at a slower interval. Moved the shifter to reverse, same issue, faster interval. Moved shifter to drive, same interval as reverse.
Researching on it from past generations of 6.7’s has lead me to FCA, Fuel Filters, MAP, IAT, and finally HPFP and injectors. Just trying to rule out the common denominator I have re-flashed the truck to a refreshed version of the current tune, and verified there is no water in fuel.
Drove across town to an appointment and noticed when I would roll off the throttle and back onto it I could watch the fuel injection pressure drop to 2.5k psi and the rebound to between 6 and 8 k psi. Rough idle was back, not as noticeable but still there. After I got home I reflashed to stock fuel mapping to verify issue is not being caused by software and is coming from a hard part. Which is where I am now.
Current plan of attack is to swap back to OEM filters as I cannot confirm flow ratings of CAT filters. Run Hotshots Diesel Extreme thru fuel system, I already run Hotshot EDT on every fill up. Verify no possible leaks or air suction at any of the low pressure fuel system. Check volume and pressure of lift pump. After that I am down to replacing parts. All sensors minus FCA have been checked and cleaned.
Any ideas from the folks on here? Dealership is not an option.
Sent from my iPhone using Tapatalk
Anywho, I am working thru an issue with fuel pressure fluctuations at idle and under load. The truck is a 21 6.7 SO with the 68RFE, Ez Lynk with CCS tuning, Black Market Performance Cat filters front and rear, and a Banks CAI, with 24k miles, no warranty.
So I noticed the issue about a week ago after exiting the freeway and sitting at a red light. Truck was acting almost like it had a random misfire. I checked codes and got U0002 which came back as pretty much nothing. Deleted code and it never came back. No CEL no issues until this past weekend. The wife and I we’re coming back from the store and came to a stop sign. Same issue of a rough idle, no code this time. Got home stopped in the driveway, same issue. Moved the shifter to park, issue stopped intermittently, then started the rough idle but at a slower interval. Moved the shifter to reverse, same issue, faster interval. Moved shifter to drive, same interval as reverse.
Researching on it from past generations of 6.7’s has lead me to FCA, Fuel Filters, MAP, IAT, and finally HPFP and injectors. Just trying to rule out the common denominator I have re-flashed the truck to a refreshed version of the current tune, and verified there is no water in fuel.
Drove across town to an appointment and noticed when I would roll off the throttle and back onto it I could watch the fuel injection pressure drop to 2.5k psi and the rebound to between 6 and 8 k psi. Rough idle was back, not as noticeable but still there. After I got home I reflashed to stock fuel mapping to verify issue is not being caused by software and is coming from a hard part. Which is where I am now.
Current plan of attack is to swap back to OEM filters as I cannot confirm flow ratings of CAT filters. Run Hotshots Diesel Extreme thru fuel system, I already run Hotshot EDT on every fill up. Verify no possible leaks or air suction at any of the low pressure fuel system. Check volume and pressure of lift pump. After that I am down to replacing parts. All sensors minus FCA have been checked and cleaned.
Any ideas from the folks on here? Dealership is not an option.
Sent from my iPhone using Tapatalk
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