LS1/LS2/LS3/LS4/LS7 etc. - LOGGING, ADJUSTING INJECTOR SLOPE

08Chevy · Post by **08Chevy** » Sun Jun 28, 2009 7:53 pm

hmm. Ok. I adjusted like you said to 4% but I have not driven it yet so I will put some miles on it and let you know. Thanks for the help.

08Chevy · Post by **08Chevy** » Sat Jul 04, 2009 12:07 pm

It works great and now it says no adjustments needed. So I did a WOT log and it says to adjust the low rpm's to -4% and the highs to -6%. Can yall help me out again.

CANUCKPREDATOR · Post by **CANUCKPREDATOR** » Sat Jul 04, 2009 1:43 pm

That adjustment is your PE (Power Enrichment)

Post by **06MonteSS** » Sat Jul 04, 2009 6:48 pm

yep..

you adjusted your injector slope to -4%, right?? so, adjust your PE (Power Enrichment - that's your WOT fueling) to -4% in all RPM ranges as well....

08Chevy · Post by **08Chevy** » Sun Jul 05, 2009 10:32 am

yes the slope is -4% and it said "no adjustments needed" on the ltft so then I did the WOT log and now did the PE tuning to low rpms -4% and the high rpms to -6%.

What does the PE actually do?

05Z71 · Post by **05Z71** » Sun Jul 05, 2009 11:05 am

PE is your fueling at WOT. By going -4% you will be adding more fuel at WOT than you do with no adjustments.

Post by **06MonteSS** » Mon Jul 06, 2009 8:51 am

nope 05z... WOT works the opposite of injector slope...

for the WOT/PE fueling, going negative removes fuel - makes you leaner... going positive adds fuel - makes you richer...

for part-throttle injector slope, going negative tells the ecm that your injectors are smaller and to spray more fuel - making you richer...

going positive on injector slope tells the ecm that your injectors are bigger and to spray less fuel - making you leaner...

now, when you adjust your injector slope negative to spray more fuel and make yourself a little richer, that also affects WOT/PE fueling - it will make that richer as well, so to compensate for that, you go negative on the PE fueling to remove that extra fuel that you added by adjusting the injector slope.

05Z71 · Post by **05Z71** » Tue Jul 07, 2009 7:47 pm

Awe hell Lew, this +- WOT PE Slope stuff is so fucked up man. I never understood why adjusting -% on Slope means you are running richer. Just doesn't make sense to me, but it is what it is and I just roll with it.

Post by **06MonteSS** » Tue Jul 07, 2009 8:16 pm

no worries man... that's why I'm here to steer ya in the right direction...

HAHAHAHAA!!

here it is again, in a nutshell...

negative slope tells the ECM that your injectors are smaller and to spray more fuel - so since they're spraying more fuel, it makes you richer.

positive slope tells the ECM that your injector are bigger and to spray less fuel - so since they're spraying less fuel, it makes you leaner.

BUT...

for the WOT/PE fueling table... you are adjusting the fueling table directly, not the injectors...

so, by going negative on PE fueling, you are removing fuel - so, less fuel makes you leaner.

and by going positive on PE fueling, you are adding fuel - so, more fuel makes you richer...

see?? piece-a-cake!!

loweredd · Post by **loweredd** » Fri Jul 10, 2009 12:27 pm

Is it normal for the tune to be spot on with LTFT's? Most of the time on my log, both banks were right at 0. I loaded it up in the redux, and it said no adjustments needed.....

However, the A/F was at a constant 14.75? I haven't done any WOT logs, the regular one took about 15 tries for DataViewer to pull it from the tuner.

*EDIT* It says my average Bank 1 was -1.13961% and Bank 2 was -1.37433%.

Post by **06MonteSS** » Fri Jul 10, 2009 12:37 pm

yeah, those average ltft numbers are good... right between the 0 to -2 range you want to be in....

the AFR will always be at 14.75 during normal part-throttle driving... that's what the fuel trims are used for, so the ecm knows how much to adjust the amount of fueling to in order to keep the part-throttle AFR at the stoich value of 14.75...

when you go WOT though, you'll see the AFR change...

loweredd · Post by **loweredd** » Fri Jul 10, 2009 12:39 pm

Ah! OK. I was hoping I was going to be able to change something. :drivingbad:

bkel33 · Post by **bkel33** » Mon Sep 14, 2009 3:29 pm

My car is a 99 LS1 C5 corvette with heads, cam, rockers, injectors, nitrous, headers, A4 auto transmission. My wideband gauge reads about 9.5 on part throttle. I have changed the injector slope to adjust for my larger injectors a pretty significant amount, but my a/f ratio doesnt seem to change any. The car is running pretty rich. Anyone have any ideas/ suggestions?

BTW - my LTFT are about -15, i've added about 30 to the injector slope but no change

spike1 · Post by **spike1** » Sat Nov 14, 2009 2:56 pm

I've been following this post and tried it on my '01Z71, did the adjustments then drove it for a while and just logged another run but, now it won't down load. I've gone through everything to see why, the usb cable is loaded on the computer but, ? it worked the first time?

Post by **06MonteSS** » Sat Nov 14, 2009 3:02 pm

did you actually save the log file?

when the log was full, did you click continue, and then press the ESC button to get back to the main menu before you unplugged the predator??

if you just unplug the predator at the end of the log, it will not be saved...

so what were the exact steps you did?

is it the log file won't download, or are you getting errors with the dataviewer program itself?? if so, what is the error you're getting?

LS1/LS2/LS3/LS4/LS7 etc. - LOGGING, ADJUSTING INJECTOR SLOPE

99 Corvette - unable to adjust injector slope