P0089--truck runs fine

[mike diesel]

Installed my new injectors last wednesday night, took it for a drive and it runs great.

Dynoed the truck thursday on tune 3 while taking a log of the run, made 980hp on 1850us and holds rail all day long. While reviewing the log, I checked for DTC's and saw a P0089. Check engine light never set and the truck runs great.

Cleared the code and let the truck sit for a minute to cool down. Switched to tune 5 and dynoed again, made 1220hp with smoke rolling off my tires. Checked for DTC'S and the p0089 was there again, but once again truck runs great and it never set the CEL.

This code started popping up immediately after the new injectors went in. Didn't touch anything else. Same PSI from the lift pump and everything.

Only thing I can think of is that since I run my lift pump pressure at 15psi, one of the regulators is being pushed open, but it's never set this code with the old injectors. Both regulators are rather new as well.

From the searching I did, it seems this code sets the CEL and causes the truck to run funny/sluggish and can cause odd starting. I dont experience any of these issues.

Does anyone have any experience with this?

 

[mike diesel]

I saw that Dustin from diesel addiction mentioned that this code can be set when desired rail pressure and actual rail pressure don't follow each other close enough.

I did notice with my lift pump set at 15 psi after letting off the throttle my desired rail goes back down to 4500ish psi but actual will hover around 8000psi for a few seconds then it will work it's way back down to 4500ish after maybe 10 seconds. But it did this exact same thing with the old 100% injectors and it's never set that code.

 

[Bonestock]

Mike there is a good chance that in your tune the cel is shutoff or not reported for p089. All that means is it wont light the check engine light. I think you may have hit the nail on the head with 15psi taxing the fuel psi regulator. Congrats on killer horsepower man! It has been fun to watch you progress on big numbers. How is your trans holding up to that kind of power?

 

[Bonestock]

There are two spots in tuning to actually turn off or set p089 to not report to ecm and where you can just turn off the mil by not reporting.

 

[mike diesel]

I emailed zach about it, we'll see what he says.

Trans holds great. Shifts like a boss. Going to the track friday, see if I can get close to 135mph trap.

 

[mike diesel]

Also, after I install the sump on wednesday, I'll turn the pressure down to around 11psi and see if anything changes.

 

[hondarider552]

Mike do you still have stock hard lines on the frame rail? May be time to remove them and run 1/2" all the way up.

 

[mike diesel]

I have 1/2" feed from tank to engine bay, then to a distribution block with 3/8" feed to each cp3. Thinking I'll run 1/2" feed to each cp3 though.

 

[Bonestock]

Also, after I install the sump on wednesday, I'll turn the pressure down to around 11psi and see if anything changes.

Ya just play with your psi a bit to find a happy spot. 8-12 psi usually is fine. Anything much over 12 the reg gets taxed pretty good. I was running like 18psi and rail @ idle was 8k. I turned it down to 10 and rail was 4.9k