LML Help??? Lml P0087 Reprogram flow rate?

[TxDmax88]

Please excuse me I'm a FNG here. Please move if needed. I have a 2015 lml that I had the fuel system take a turn for the worst. Replace pump, fuel lines and all 8 injectors.

Truck runs ok, poor mileage and throws a p0087 (low rail pressure)
Do I have to reprogram my flow rates from new (stock) injectors?
Is this why my mileage is poor and still throws the p0087???

Any knowledge would be much appreciated!

 

[Chevy1925]

CP4 is timed to the cam gear. did you time the new one properly?

 

[TxDmax88]

Yes I believe so. The One dot on co4 gear is in between the to on the cam gear.

 

[TxDmax88]

I can clear the code and it runs great ( tune wise) but eats fuel. I make a 86 mile drive and it eats a 1/4 tank of fuel

 

[TheBac]

Moved this to LML area.

Please dont start new threads dealing with the same issue.

I believe you do have to program the new injector flow rates, but dont quote me on it. You probably should be calling a dealer or trusted diesel shop by now.....

 

[02greysixer]

I don't know if it will affect fuel mileage but programming the flow rates will definitely make the engine quieter and smoother. Wouldn't be surprised if it helped fuel mileage.

Don't think it will help your low rail code though. Did you replace fuel rails and flush all lines and clean the tank?

Sent from my SM-G930P using Tapatalk

 

[TxDmax88]

I don't know if it will affect fuel mileage but programming the flow rates will definitely make the engine quieter and smoother. Wouldn't be surprised if it helped fuel mileage.

Don't think it will help your low rail code though. Did you replace fuel rails and flush all lines and clean the tank?

Sent from my SM-G930P using Tapatalk

Yes I replaced rails and cleaned everything out.

Update!
I cleared the code, reduced my tune to the tow tune and run all day without throwing it (extremely crappy mileage...DTC says 13 and it went down to 8mpg), if I sit and idle for a few hours and go down the road it will throw the 87 code. I'm lost in this one.

 

[Chevy1925]

is your lift pump working? do not use the DIC for mpg, hand calc it. when did you change fuel filters last including the stock one?

 

[TxDmax88]

Yes is working, getting fuel to the filter housing, and filters have less than a 1000 miles. Checked the filters twice and no leaks. I will hand calculate my mileage this afternoon when I go to work.

???! Could it be the fuel rail pressure sensor on the back of the driver side rail? Just a thought.. if it was messed up or failed could it allow the Fprv on the front side of the rail to open and dump fuel? Wouldn't it throw a code though?
I also read something about if the Fprv isn't torqued correctly it will not seat right and will leak..

 

[Chevy1925]

if the FPRV is leaking, it could very well cause this.

 

[TxDmax88]

Ok finally woke up... these night shifts are getting old.

Ran the Display data on my autocal.. to be honest I have no clue what I'm looking at. If y'all see anything out of ordinary let me know.

Running at idle for about 10mins.
ECT-76*C
Mninjtim-2.1*
Frpcom- 38.0%
App- 0.0%
Baro-100kpa
Frp_c- 31360.0k
Maf-35/36g/s
Iat- 60*c
Vss- 0km/h
Rpm-665rpm
FuelRcal - 7.7mm3
Tcvpos- 9.8%
Frpdi- 31360 kpa
TcBGP- 3.3kpa

 

[TxDmax88]

Wouldn't I get a code if the FRPV was leaking tho???

 

[TxDmax88]

On another note I just noticed my fuel gauge fluctuating.. I have the Digital display. Wonder if there's something going on there to Mess with the DTC mileage readings

 

[TxDmax88]

And I forgot to mention that I get a change fuel filter message on the DTC. Been on the whole time.

 

[Chevy1925]

let the truck idle and tell us what the actual fuel rail pressure is and the commanded/desired fuel rail pressure is. what you posted above from teh CTS shows the truck trying to command 31k rail pressure. something is wrong.

what are your fuel temps at idle? coolant temps? not based off the stock dash, i need to know off the cts

 

[TxDmax88]

I can't see the desired rates at this time bc my computer is down..

Update.. Today I have been experiencing hard starts. Once started runs fine. Still have the 087 code pop when I first get going, can clear it and doesn't pop again.. while at work I leave my truck running for a extended period of time, no light, when I leave it will pop the 087 code around 2-3k Rpms. Any ideas???

 

[Chevy1925]

i need this info i asked for or we are just shooting in the dark

 

[SickLL7Crenshaw]

I've seen on 2 trucks where the cp4 failed it also took out the rail sensor. Both were only see 18-19k rail WOT while desired 29k and would throw the P0087.. Replaced and issues were fixed.

 

[kvw4x4]

We went through am issue with a bad cp4 fuel pump. Replacing everything.... and I mean everything. Anything the fuel touches needs to replaced. We flushed complete fuel tank including sending unit in tank fuel lines to engine and return lines from engine. All hard and soft lines on engine. We had the fuel rails cleaned with a special sonic or something cleaning machine. Also had all hard lines done we replaced injectors and fuel filter including fuel filter assembly. We still ended up having a loss of power issue over 2300 rpm. No codes tho. Ended the only thing we didn't clean was the injector return lines on engine that head back to tank. The injector return lines from each side of engine y together through a regulator. The lml injectors will not function properly without the right back pressure, hence this regulator, ended up replacing that part and the truck finally ran good. We did have efi live tuning and motor ops helping with tuning issues also.

 

[TxDmax88]

Ok Fellas, I've fixed the P0087 code. Long story short truck wouldn't start yesterday evening , for some reason I tapped on the FPRV and it started.. replaced the FPRV today and no code as of yet

On another note i now throwing a p1224 and/or P2146. Only pops code when I seem to hit a bump. Any location I should start looking for the short???