I read this article in this month's Chevy High Performance. It's a good read for those novice tuners or for those just starting out. I hope there's more where this came from.

http://chevyhiperformance.com/techarticles/0508ch_obd/

Learn it, know it, live it. :)

Thanks!

i would do the HP tuners if i was not so afrade of screwing up the pcm.
drilling the carb, changing the jets, any thing to make it work faster or dump more fuel, upgrade the distributer, setting the timing, increase spark, no problem.
now that it is all done by a computer it is almost beyond me,
everything i know how to do is just not needed any more.

awesome... i'll put that to some use.

one question...

under General Fuel System Adjustment,
"For example, if your average LTrim is eight, this means the PCM is adding 8 percent more fuel. So try scaling the entire MAF table by 1.08..."

where did they get this 1.08 number? whats its significance?

Wish I could answer that, but I haven't got into my fuel trim settings yet.

Have to find a good day I can spend logging and driving around.

awesome... i'll put that to some use.

one question...

under General Fuel System Adjustment,
"For example, if your average LTrim is eight, this means the PCM is adding 8 percent more fuel. So try scaling the entire MAF table by 1.08..."

where did they get this 1.08 number? whats its significance?That would simply mean the baseline is 1.00 and 8 percent (.08) increase would be 1.08. If you multiply any number by 1.08 the result is an 8 percent increase.

i would do the HP tuners if i was not so afrade of screwing up the pcm.
drilling the carb, changing the jets, any thing to make it work faster or dump more fuel, upgrade the distributer, setting the timing, increase spark, no problem.
now that it is all done by a computer it is almost beyond me,
everything i know how to do is just not needed any more.

If you can tune a carb, then tuning efi shouldn't be all that hard for you. I grew up and I am still, playing with carbs and when I read about how its done with efi, its all the same. Its generally the same process, just instead of screw drivers and wrenches, its done with the stroke of the keyboard. :)

That would simply mean the baseline is 1.00 and 8 percent (.08) increase would be 1.08. If you multiply any number by 1.08 the result is an 8 percent increase.

oh.. duh... awesome.. thanks!

i just need to go buy a card so i can hook the laptop upto my truck.

This is awesome for the rookies. That includes me!!

But I have one question for the professionals. If you are seeing a +8 on your LT trims (meaning that you are adding fuel because of a lean condition), and then go to your MAF settings and adjust it by 1.08 would'nt that make your LT trims increase since you are adding more air, thus making it leaner??? I am confused on this one

If you multiply the MAF readings by 1.08, you're not adding more air, your just telling the computer its seeing more air than it thinks it is. Your re-calibrating the MAF signal vs. its output frequency. Hence the lean condition. Does that make sense. Why on earth the computer won't adjust is freakin' stupid but thats the way it goes.

For example lets say you have a factory tune, and you put a nice phat cam in the engine. Cool! But the factory tune and MAF have been designed to work for a certain amount of air and fuel. With the cam you're adding more air so you can burn more fuel. The MAF hasn't been calibrated to work with the higher airflow rates its seeing. So you use the O2 sensors output signal (L trims), and adjust the MAF accordingly. This in turn fattens up the mixture and tunes the engine. :)

This is just my take on it. This is so similar to carbs its almost scary. :D

what are ya doin his weekend todd?.. wanna break out the HPT?

Thanks for posting that link. I printed a copy for future reference. I think I can see HPTuners in my future. :) :chug:

what are ya doin his weekend todd?.. wanna break out the HPT?

I'm totally up for it, I have nothing planned! If Beto whats to come too, we'll all pile in and be truck geeks together! :)

I get dibs though, since my truck is by far in the worst shape.......POP, POP, POP...BOOM.....BANG! :bomb: :barf:

I'm totally up for it, I have nothing planned! If Beto whats to come too, we'll all pile in and be truck geeks together! :)

I get dibs though, since my truck is by far in the worst shape.......POP, POP, POP...BOOM.....BANG! :bomb: :barf:


it will have to be sunday, if thats ok with you guys. i'll be in phoenix saturday night....

so maybe we can do it tomorrow too. :usa:

I am trying to figure what I am going to do, still trying to make some room in the schedule for this, will let you guys know in a bit!

I am trying to figure what I am going to do, still trying to make some room in the schedule for this, will let you guys know in a bit!


ok just give me a call... i leave for phoenix in a few hours.

ok just give me a call... i leave for phoenix in a few hours.

PM your number I lost it. Also it looks like I will have some time tommorrow about the middle of the day, when it is only 100+ outside. I am going to go eat breakfast with my dad in the morning and then have a group meeting at around 7:30pm tommorrow.

PM your number I lost it. Also it looks like I will have some time tommorrow about the middle of the day, when it is only 100+ outside. I am going to go eat breakfast with my dad in the morning and then have a group meeting at around 7:30pm tommorrow.

PM sent.

call me!

I will call you in a while (I am at the U working on some stuff), you are the priority fool, cause when we are done, people are going to be calling us for tunes biatch.

did you check the cats.

call me!

for 2morrow right?

I will call you in a while, you are the priority fool, cause when we are done, people are going to be calling us for tunes biatch.

did you check the cats.

LOL... its my program!!!!!!!!!!!!!! :jest:

LOL... its my program!!!!!!!!!!!!!! :jest:

do you have the program for his year? Or do you guys have the same year truck?

do you have the program for his year? Or do you guys have the same year truck?

Gotcha I see that both of you have the same year. I will call yall in a bit!