My SES light is illuminated w/Granatelli MAF, but dyno showed 15 HP increase with it installed (over stock MAF), so I am going to keep it. Codes popping up on shop's autotap were P0171, and P0174, both leanbank conditions. I think once A/F is richened, dyno might show even bigger HP increase....

I am purchasing a Predator tomorrow, but wonder if I need to purchase Autotap also. All I want to do, is richen A/F to around .88 - .90 to try for 13 to 1 ratio. That should stop the SES light from staying on w/GMAF.
Will Predator show those specific #'s? Or does Predator only let the user increase fuel by "+5%", or "+10%", without giving exact o2 readings? Thanks for all feedback!!!

 

Predator only lets you adjust by %'s, no hard numbers. For sure you can richen it up probably past where you want to be. Put it on a dyno and adjust the power enrichment tables according to the A/F. Simple as that.

 

You probably get the SES light from closed loop normal
operation. The Predator only messes with the power
enrichment (PE) and my guess is that your problem is
being too lean at lower throttle. Fixing WOT may not
do anything for the SES light.

Predator can make you a tune that comprehends the
GMAF if you want (at least, if you are with a vendor who
cares to support the product).

Your adjustment range (5%) is probably not going to
be enough to overcome a code-setting (25%) mixture
problem. You have to get the thing trued up to at least
"close".

 

ditto

 

Hey Venkman and Jimmyblue,

Thanks a lot for your input. Jimmyblue, I understand exactly what you said, but if this was your car, what would you do? I am tempted to ignore the SES light, PROVIDED I have Autotap done after installing 160 Tstat, and Predator tune (which will richen 5% and kick on fans at 175-180). HERE ARE DETAILS:

I had Autotap run on Dyno (which showed the HP gains w/GMAF), and it clearly shows stock MAF running way too rich --
.98-.95 B1S1 and B2S1 through 2200 - 6000 RPM's. Last pull w/stock MAF, H2O temps were way up at 230, and readings were .94-.92 (SES light would never come on with STOCK GMAF -- no wonder, way too rich isn't as big a deal I suppose)

GMAF was tested before stock MAF, and 1st pull showed .95-.91 ranges (.95 at 2200 RPM's, .91 at 6000 RPMS) H20 temp was 190. On 2nd pull w/GMAF, H20 temp was 201, and showed ranges .90 - .87 (I have read these are IDEAL #'s!!) The SES light was on when GMAF was being tested. I am just wondering if I ensure Autotap reads above .88 w/SES light on, how could this ever cause damage? The engine runs great w/GMAF, but SES light concerns me!
Thanks for any and all feedback!!

 

Your stock Mass air with a leaner A/F will give the same HP as the GMAF.
Since Diablo does not do lower rpm changes(as stated)I would suggest a MAFT so you can richen up the base.
With your engine light on because of lean banks,yes it can possibly hurt the motor running as lean as you are.

 

HEY! I know you!

Your lean codes are partial throttle NOT WOT. You need a way to fatten up partial throttle without changing WOT. Your WOT is great.

I'm not sure if Preditor can do that or not. I know LS1Edit can.

 

That's what I found in my dyno testing as well. The GMAF doesn't make power due to increased airflow, but because it changes the A/F ratio.

I'm surprised his car was running that rich with the stock MAF. He does have a CAI instead of a lid (kinda like a blackwing), which may account for the problem.

 

Does the GMAF richen or leans ??

 

A "off-the-shelf" GMAF drops 02's about .03-.05 volts. It leans out the motor.

 

Your other option is to put the stock MAF back, and use
tht Predator to -subtract- PE, making your low-throttle
probably right on, and leaning out WOT. This might do
the job for you. Costs nothing (more) to try....