Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums -
Go Back   Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums - > Engine | Drivetrain | Powertrain Technical Discussions > Tuning / Diagnostics -- engine and transmission

Thread Tools
Old 01-15-2013, 10:44 PM   #1
Seeking 9s on M6...
PMJ's Avatar
Drives: 2012 2SS/RS LS3 aka "BlackWidow"
Join Date: May 2012
Location: Houston, TX
Posts: 395
Question Questions on new ZL1 Fuel Pump install

I recently installed a ZL1 fuel pump in preparation to install a cam that Iím expecting to help me reach 650+ rwhp. Since my install, I think Iím having problems...(I'm not a tuner, but like to dabble a little...very little).

First my variance from commanded AFR has increased drastically. When commanding 14.7, my variance used to be from around 15.3 - 14.3. Now Iím seeing from 17-13 (that's on the extreme side, but it is always significantly greater than I'm used to seeing) - and that's w/a very steady fuel pressure 58psi. The irritating thing is i occasionally knock when it goes to the lean side w/the throttle at <15%.

The other problem Iím seeing is pictured below. As you can see, when the commanded AFR drops from 14.7 to 11.56, my actual AFR goes lean before trending to the commanded AFR. As you can see in the log, I had some nasty knocking when that occurred.

I am seeing my fuel pressure dip when transitioning to PE around 50psi, in the log below it goes as low as 46 psi...the problem is I never logged fuel pressure with my original fuel pump, so i don't know if this is normal behavior.

Some additional information that I don't think is causing the problem, but will disclose just in case...I am running a boost-a-pump (planning to disable based on what I've read aboug the ZL1 pump), and I also recently installed an Alky Control Meth kit...which was spraying during the screen shot below, but I am seeing the same problems when I'm not in boost and the meth is not spraying.

Any thoughts on what would be causing the high variance and more importantly the going lean when transitioning to PE mode? (unfortunately i decided against cutting an access door to my fuel pump, as i had a set of BMR bushings I decided to install as well, so it made it worth my time to drop the rear about a job from hell, removing the stock bushings from the diff and A arms is something i never care to do better improve my 60' by at least a tenth )

PMJ is offline   Reply With Quote
Old 01-16-2013, 04:54 AM   #2
Iam Broke
Iam Broke's Avatar
Drives: 2012 TF3 Camaro 2SS/RS M6
Join Date: Jun 2012
Location: Dark of the Moon
Posts: 1,468
I see you are logging commanded FP DC, add the actual FP DC to the scanner. I know Jennetty has info on how to wire a BAP correctly for our cars, may be your issue.

Since the stock commanded FPDC is 90% maxed out I see you (or your tuner) already raised that to 100% or the PID is invalid. I can't check mine right now as it's all apart. lol.

I tend to think it's in error since it's flatlined or the BAP is confusing the stock FP controller.

Might be worth posting in the Gen 4 section on HPTuners.
Another 1 of 371 '12 T3 LS3 M6's built.
Iam Broke is offline   Reply With Quote
Old 01-16-2013, 10:18 PM   #3
The 2010 Sin
Dont H8 Me Cuz U Aint Me
The 2010 Sin's Avatar
Drives: 2016 SS Sedan, 2017 Explorer Sport
Join Date: Feb 2010
Location: Tulsa, Oklahoma
Posts: 2,898
Not sure if the FP command is supposed to be over 90. You may have an error if you haven't changed that.

Lol.. this is what i get for not reading all the posts... "MYBAD!" ^^ What he said!

Last edited by The 2010 Sin; 01-16-2013 at 10:19 PM. Reason: OOPS...
The 2010 Sin is offline   Reply With Quote
Old 01-18-2013, 10:50 PM   #4
Seeking 9s on M6...
PMJ's Avatar
Drives: 2012 2SS/RS LS3 aka "BlackWidow"
Join Date: May 2012
Location: Houston, TX
Posts: 395
So after further investigation looks like I was chasing a non-existent problem due to multiple mods at the same time. The AFR going lean when shifting is actually normal when you let off the throtle due to the decel. I did change a setting in my tune that seemed to reduce the time to return to commanded...I changed Power Enrickment - Enrichment Ramp In = 2 (previously 1).

My knocking was due to me switching from running torco to meth, but the meth was not tuned yet. Now I have my meth tuned and running good.

Few outstanding questions I have...

1) My new ZL1 fuel pump drops pressure to 45 PSI WOT at 6000rpm. It does not change whether my BAP is on or off (and i verified my BAP voltage is changing as expected from 14-17v. So what was the advantage of the ZL1 pump??? I thought it was to maintain pressure at higher hp, but i'm not seeing it.

2) My FP Commanded DC stays at 99.6 regardless of my Pump DC and DC Max settings (the Whipple tune changed them to 99%; w/the ZL1 pump, I rolled back to 90%, however it continues to read 99.6.

In the end, i'm running rich (as I desire) w/no knocking all the way through my pull, so on to my new cam install...


Last edited by PMJ; 01-18-2013 at 11:17 PM.
PMJ is offline   Reply With Quote

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

All times are GMT -5. The time now is 03:58 AM.

Powered by vBulletin® Version 3.8.9 Beta 4
Copyright ©2000 - 2018, vBulletin Solutions, Inc.