[Atomic Ed]

For those of you that have changed out your SS LPFP with a ZL1 pump, did you modify your FSCM tables?

I'm picking up a P2635 code; "Fuel Pump ‘A’ Low Flow / Performance". I think I need to modify the max desired pressure table to bring the ZL1 pump's capability up to speed.

I am a noob on tuning these beasts and could use some guidance.

[Atomic Ed]

Using HPTuners 3.7 (beta), I was able to open up the FSCM and change the Max Desired Pressure tables under both the FSCM tab and the fuel pressure tab and hand modify both tables to this. l also upped the normal fuel pressure to 50.8 psi (ZL1 value) in the fuel pressure tab. This table is my effort to merge the ZL1 stock table with a '16 SS table, keeping the pressures high, but with the falloff that both tables have.



This is a noob fix BTW, but it worked! THE DTC code cleared and hasn't come back. I did several runs yesterday confirming that the LPFP pressure is up and aligns with this table. Several full pulls confirmed that the pressure never went below 55 psi throughout the pulls. With the stock FSCM tune, pressure would drop to around 40 psi.

With access to the FSCM, I think there is more potential to bump up the in-tank to support the overall fuel system when there is marginal flow as well as fine tune the LPFP to support the HPFP better.

And as a note, the FSCM flash gets wiped out every time you read your ECM/FSCM. So be sure to write back your file after each read.

[JFM-jr]

I dont believe it gets wiped out. When you do a read it will give you the same "base" file as a read regardless of what tuning changes actually exist in the FSCM making retrieving any tuning currently existing in the FSCM unextractable. You would need to flash the FSCM for any actual tuning changes. At least this is how I understand it and if any tuners on the board here could confirm or correct this please do so.

Interesting you were getting a CEL as this is the 1st I have heard of anybody having this issue after a pump swap.

[Atomic Ed]

Originally Posted by JFM-jr

I dont believe it gets wiped out. When you do a read it will give you the same "base" file as a read regardless of what tuning changes actually exist in the FSCM making retrieving any tuning currently existing in the FSCM unextractable. You would need to flash the FSCM for any actual tuning changes. At least this is how I understand it and if any tuners on the board here could confirm or correct this please do so.

Interesting you were getting a CEL as this is the 1st I have heard of anybody having this issue after a pump swap.

Interesting thought on your part. My last comment was just a regurgitation of info I pulled off of the HPtuners forum. I'm really not familiar with these new-fangled networked systems on these cars, so thanks for the feedback.

Seems like a simple crosscheck would be for me to read the tune file and then go back out a do a logging run. If the LPFP is behaving the same as before the read, we're good. I'll give it a try this weekend.

[JFM-jr]

I flashed my FSCM to remove the AFM DTC codes. I have since reread the file after the flash (reads as a stock file again). I have driven the car and no CEL so the flashed file is still in there. I think the important thing here is to save a copy of the last flashed file as it will be the only retrievable record of what currently exists in your module.

[Atomic Ed]

Originally Posted by JFM-jr

I flashed my FSCM to remove the AFM DTC codes. I have since reread the file after the flash (reads as a stock file again). I have driven the car and no CEL so the flashed file is still in there. I think the important thing here is to save a copy of the last flashed file as it will be the only retrievable record of what currently exists in your module.

Thanks for checking. I've got a long journey ahead learning about this system.

[Choda]

Originally Posted by Atomic Ed

Using HPTuners 3.7 (beta), I was able to open up the FSCM and change the Max Desired Pressure tables under both the FSCM tab and the fuel pressure tab and hand modify both tables to this. l also upped the normal fuel pressure to 50.8 psi (ZL1 value) in the fuel pressure tab. This table is my effort to merge the ZL1 stock table with a '16 SS table, keeping the pressures high, but with the falloff that both tables have.



This is a noob fix BTW, but it worked! THE DTC code cleared and hasn't come back. I did several runs yesterday confirming that the LPFP pressure is up and aligns with this table. Several full pulls confirmed that the pressure never went below 55 psi throughout the pulls. With the stock FSCM tune, pressure would drop to around 40 psi.

With access to the FSCM, I think there is more potential to bump up the in-tank to support the overall fuel system when there is marginal flow as well as fine tune the LPFP to support the HPFP better.

And as a note, the FSCM flash gets wiped out every time you read your ECM/FSCM. So be sure to write back your file after each read.

interesting, your values are drastically different than mine. I am also trying to solve this CEL. Mine are 560 pressure up until 154.8lb/h. then slowly decreases to 328 pressure at cell 381lb/h.

[wnta1ss]

Originally Posted by Choda

interesting, your values are drastically different than mine. I am also trying to solve this CEL. Mine are 560 pressure up until 154.8lb/h. then slowly decreases to 328 pressure at cell 381lb/h.

His screenshot of a modded SS table is in psi, and you're seeing kpa. ZL1 table ECM 6975 starts at 560 kpa and tapers down to 500 kpa at 444.5 lb/hr fuel flow. Will attach screenshot of ZL1 below. Note the higher max fuel flow value for the car that burns a lot more fuel. Also note that cjperformance found he needed to fix his FSCM table as well as the ECM, to get his car working correctly with a DSX add-on low side. Seems the computer was trying to lower the pressure in his case? You can check his Procharger 1/4 mile thread for details.

[wnta1ss]

Here's a 'read' of an SS FSCM. Generic from HPT from what I've heard, so save your modded file if you license and flash it, because you cannot actually read the module, from what I understand.