Having Fuel Pressure Issues- LSA setup/ZL1 pump E38 pcm

[kelleyperformance]

hey all, so basically heres whats going on- I was hoping for some insight from someone(s). basically first off, here is the setup/details-
-The car is a 2014 Chevy SS LS3 w/ LSA blower (stock, not ported) w/ 2.85" pulley (stock is 2.95"); LS9 cam; stock LS3 heads; Kooks 1 7/8" LTs

These SS cars have been confirmed via physically (by removing fuel pump) AND running VIN of ZL1 and SS sedan to check fuel pump module P/N's- they use the same fuel pump for sure.

Despite using the same fuel pump, they show different p/n for FPCM; however, IMO this should just be a matter of the SS sedan coming with all low, std, and high flow settings at 58 psi; where as the ZL1 comes with varying fuel pressure depending on conditions- mainly that it increases fuel psi under boost conditions (yes I know its not by boost, its by fuel flow lol- but it comes in DURING boost). SO my opinion is that's the only difference, hence tuning my FPCM to the same manner as the ZL1 FPCM data should produce the same results, by all logic....

SO Heres whats going on- we started noticing that at WOT, or at part throttle / high load / 5-7 psi boost (peak boost 9.5 psi) that the fuel pressure actually just immediately drops from the commanded 58 psi to exactly 50 psi, starting around 3750 rpm running up and up, yet it isn't exactly continuing to fall. as a speed shop specializing in LS setups, most with returnless OEM systems, ive seen my fair share of Walbro's running to their limit and watch the rail pressure steadily drop and continue to drop "in sync" with the increasing RPM. Yet THIS just jumps straight from 58 to 50 psi, like almost as if it was commanded, and as the RPMs climb, it just isn't falling further... So we commanded it 68 psi under "high flow" conditions, and logged commanded fuel PSI and actual PSI... SAME thing... it never even tries to raise to the 68, never goes over 60 even when I lowered the threshold for the highflow mode so it would command 68 psi under lighter conditions that seem impossible to be overcoming a ZL1 pump with the simple mods on the car, at 1-2 psi over stock boost... and we are talking 4k rpm here not 6600! so is there something im missing, is my SS sedan's FPCM just not able to accept these modified pressures? because from my professional experience, I cannot see this setup overwhelming the decent sized ZL1/V fuel pump setups, on 9 psi, at 4000 rpm. any help much appreciated.

Thanks,
John

[cc-rider]

You need a FPCM from ADM Performance. Unfortunately, all FPCM's are not created equal. The stock SS pump will not run the ZL1 pump like it should. They are $225 new from ADM. You can sometimes find them used on the Camaro5 forums. I don't know what ADM does to those FPCM's. But they just plain work.

Here's a good read for you: http://www.camaro5.com/forums/showthread.php?t=268524

[kelleyperformance]

You need a FPCM from ADM Performance. Unfortunately, all FPCM's are not created equal. The stock SS pump will not run the ZL1 pump like it should. They are $225 new from ADM. You can sometimes find them used on the Camaro5 forums. I don't know what ADM does to those FPCM's. But they just plain work.

Here's a good read for you: http://www.camaro5.com/forums/showthread.php?t=268524

well im not talking a Camaro SS- the car came from GM with a ZL1 pump in it. I was just comparing the FPCM to the V and ZL1, where as that does NOT match unlike the fuel pump... so your saying I cant just program mine?

since you can see their is a big difference is our cases, im just not sure I can compare my situation to a Camaro SS. why did GM stick a ZL1 pump in my LS3 powered car from factory? I have no idea... but seeing that they did, I cannot understand if they put an improper FPCM in it that couldn't even control the OEM pump that's all im saying. not arguing with your facts, or the facts in the link you sent me.

[cc-rider]

Sorry, I thought you meant a Camaro SS. That being said...I know that the FPCM's can be funny stubborn little things and very few people know a lot about them. Call Andy at ADM Performance. He's one of the experts on them. He may be able to tell you if the one in your car can be reprogrammed.

What settings did you try to change? Just the Hi/Low pressure boxes? There are other tables that need to be changed as well. At least that's what the folks at ADM recommend. Here are the settings they recommend for their FPCM. Keep in mind this is for a Camaro with an E38 computer and a ZL1 pump. Not sure how these settings would translate to a different set up. Make sure you pay attention to the units in each table and get them right if you are going to use this data.

FPCM settings - ZL1 pump with ADM FPCM.jpg

[radrace19]

The best thing for you to do would be to import an HSV one from Australia or find someone to put the HSV program into your Chassis Control Module (FPCM)
The Chevy SS and the HSV GTS use the same module in 2015+

[kelleyperformance]

your sure of this? cause why would the HSV GTS and the SS share the same fuel pump in 14'? then in 15' they decide to change the FPCM...?

[kelleyperformance]

Sorry, I thought you meant a Camaro SS. That being said...I know that the FPCM's can be funny stubborn little things and very few people know a lot about them. Call Andy at ADM Performance. He's one of the experts on them. He may be able to tell you if the one in your car can be reprogrammed.

What settings did you try to change? Just the Hi/Low pressure boxes? There are other tables that need to be changed as well. At least that's what the folks at ADM recommend. Here are the settings they recommend for their FPCM. Keep in mind this is for a Camaro with an E38 computer and a ZL1 pump. Not sure how these settings would translate to a different set up. Make sure you pay attention to the units in each table and get them right if you are going to use this data.

FPCM settings - ZL1 pump with ADM FPCM.jpg

yeah I have tried all that, and those settings are not important here as the car is not meeting commanded fuel pressure under boost no matter WHAT those tables are set to...

[radrace19]

Just because the Chassis Control Module is the same doesn't mean the programming inside is the same. GM uses the Camaro ZL1 module in many cars and the difference is the programming inside.
HSV will not let a non HSV dealer access to the custom programming for their cars so we in the US can not program the module to their specs.

Like I said you need to contact http://www.whiteautoandmedia.com/ for custom programming or try and get one from Australia.

[gmtech16450yz]

Do you have access to TIS? If so, it sounds like all you need to do is reflash the FPCM (CCM) with software from a ZL1. All you need is the VIN from a ZL1 to get TIS to access the different files. If you don't have TIS, it might be a little harder to find a dealership tech that can do it. Most of them unfortunately have no clue about using files from a different VIN.

[kelleyperformance]

Just because the Chassis Control Module is the same doesn't mean the programming inside is the same. GM uses the Camaro ZL1 module in many cars and the difference is the programming inside.
HSV will not let a non HSV dealer access to the custom programming for their cars so we in the US can not program the module to their specs.

Like I said you need to contact http://www.whiteautoandmedia.com/ for custom programming or try and get one from Australia.

yeah I know chris, he is a cool guy. hes doing my mylink and cluster actually. I already figured the issue out- it is the internal programming of why it wont match the commanded PSI. as for the 58 psi to 50 psi issue- that was due to being in forced open loop for tuning purposes. as I was reading on GM SI, I realized the FPCM will not function exactly as it should in open loop as it functions in closed loop.

Do you have access to TIS? If so, it sounds like all you need to do is reflash the FPCM (CCM) with software from a ZL1. All you need is the VIN from a ZL1 to get TIS to access the different files. If you don't have TIS, it might be a little harder to find a dealership tech that can do it. Most of them unfortunately have no clue about using files from a different VIN.

yes I do have access to Dealer World, so all the things such as SI, TIS, etc. I personally don't like to fool with modules using other VINs unless I can do them via benchtop, like a PCM with a custom harness. MOST of the time what your saying WILL work, but occasionally we have seen some disasterous things happen when using a totally different car/VIN and trying to program a module through the car's entire data network.

so in summary- the 50 psi deal was due to being forced into open loop. without commanding open loop, in the same conditions, it remained at 58 with no issues all the way to 6600 rpm @ 9.5 psi. as for why it wouldn't match commanded pressure, that's due to the FPCM's internal programming- I was under the misunderstanding that when in HPT I change the pressure settings and such, it directly changed the FPCM's settings, not stopping to think it was simply settings in the ECM.... so im just getting an FPCM that's already programmed for the ZL1 pump/boost so I can command whatever id like. thanks for the advice!

[mowton]

Well that was eye opening....like I said, never too old to learn. Symptoms versus understanding can sometimes be in conflict but the theory for why something happens usually is clear..I know that may be confusing :-)....or its a volume issue due to lack of pressure in this case....

So VCM open loop commanded exacerbated the lean condition which still existed at 58 PSI per that one log as well.

How about 11:30 or so tomorrow or do you want to wait until the FPCM gets here?

Ed M

[gmtech16450yz]

yes I do have access to Dealer World, so all the things such as SI, TIS, etc. I personally don't like to fool with modules using other VINs unless I can do them via benchtop, like a PCM with a custom harness. MOST of the time what your saying WILL work, but occasionally we have seen some disasterous things happen when using a totally different car/VIN and trying to program a module through the car's entire data network.

Yes, it is safer to only program the specific module with the others taken out of the network. It's usually not too hard to separate out the modules on the network so that you're only accessing the particular module you want to reflash. From the sound of it though you're already way ahead of most techs on using TIS, good job! I've tried to help guys get OEM radio swaps programmed to vehicles that didn't have that particular radio option stock and it's rather disappointing. I had one guy go to 5 or 6 of his local dealerships and every single one of them said it couldn't be done. This was a simple model year issue, he was trying to put a USB radio in a previous year car that didn't have the option. I even made a video showing step by step how to reflash a factory radio with the proper software to match the car it was being put in. He showed the video to a few of the techs and they said they had no idea you could select a different VIN! He never did find a dealership that could do it. He's been driving around with super loud chimes and bad audio ever since. And these are guys that are TRAINED on how to use TIS! Idiots!

[radrace19]

so in summary- the 50 psi deal was due to being forced into open loop. without commanding open loop, in the same conditions, it remained at 58 with no issues all the way to 6600 rpm @ 9.5 psi. as for why it wouldn't match commanded pressure, that's due to the FPCM's internal programming- I was under the misunderstanding that when in HPT I change the pressure settings and such, it directly changed the FPCM's settings, not stopping to think it was simply settings in the ECM.... so im just getting an FPCM that's already programmed for the ZL1 pump/boost so I can command whatever id like. thanks for the advice!

I recommend you check with Chris before buying the ZL1 module. I'm pretty sure the Camaro and Chevy SS speak different CAN/GMLAN languages and what you are wanting to do will not work.

I reprogram FPCM's on the bench and it requires an ECM hooked up also for TIS to work correctly

-Greg

[kelleyperformance]

Yes, it is safer to only program the specific module with the others taken out of the network. It's usually not too hard to separate out the modules on the network so that you're only accessing the particular module you want to reflash. From the sound of it though you're already way ahead of most techs on using TIS, good job! I've tried to help guys get OEM radio swaps programmed to vehicles that didn't have that particular radio option stock and it's rather disappointing. I had one guy go to 5 or 6 of his local dealerships and every single one of them said it couldn't be done. This was a simple model year issue, he was trying to put a USB radio in a previous year car that didn't have the option. I even made a video showing step by step how to reflash a factory radio with the proper software to match the car it was being put in. He showed the video to a few of the techs and they said they had no idea you could select a different VIN! He never did find a dealership that could do it. He's been driving around with super loud chimes and bad audio ever since. And these are guys that are TRAINED on how to use TIS! Idiots!

yes I totally agree, it is sad how poor the training and knowledge is at MANY many dealers, not just of GM origin. I have about as much experience messing with things on cars that don't belong lol- like putting TPMS on my 06' SS Silverado just had to put an 05 or 06 Tahoe PDM in it, and program it to the truck, install sensors, now I can get warnings and read my pressures. took me all of about 2 hours LOL. nice to talk to someone else who understands these vehicles too !

I recommend you check with Chris before buying the ZL1 module. I'm pretty sure the Camaro and Chevy SS speak different CAN/GMLAN languages and what you are wanting to do will not work.

I reprogram FPCM's on the bench and it requires an ECM hooked up also for TIS to work correctly

-Greg

I hear you, and thanks for the warning. but honestly my car is on a Zeta chassis, uses an E38 PCM, uses a ZL1 pump from factory... I will be using a reprogrammed LS3/E38 Camaro module. it matches the one in my car in every way possible- p/n, issues running high PWM through the ZL1pump, etc etc. it should be ok. we shall see!