Fuse Pull: Low Octane Fuel Fix For L99 and LS3. Reset Fuel Map for High Octane Fuel.

[CRTZL1]

Originally Posted by spike III

Looks like a young kid,Didn't have the twizzers for the old glass tubes.

WHAT?

[Klepton]

Originally Posted by SSRS55

Well in fact it is, it was... until a couple two three pages ago where I guy said he did it on a tuned car and he noticed the difference.. so this is why I was unclear whether or not it was needed on a tuned car....

Now THAT is an opinion. Exactly what a tune does with the octane tables is a fact...

[Scott@Bjorn3D]

Not having to worry about the fuse pull with having a tune would mean the tuner would of had to copy the high octane table of the tune also to the low table as the same. Some tuners will not do that incase you do get bad gas or can only find a lower octane.

[CRTZL1]

Originally Posted by Scott@Bjorn3D

Not having to worry about the fuse pull with having a tune would mean the tuner would of had to copy the high octane table of the tune also to the low table as the same. Some tuners will not do that incase you do get bad gas or can only find a lower octane.

So exactly what are you saying here.. it maybe necessary?

[90503]

Originally Posted by Ace1USMC

Guys, I wanted to get your opinions/thoughts on something I'm trying... So a little background first...

I've modified my 2011 SS LS3 quite a bit. Camsahft, valve springs, pushrods, timing chain, rocker trunions, billet flywheel and twin carbon ceramic clutch discs, 1 7/8" primary LT stainless headers, no cats, 3" mandrel bent exhaust into Flowmasters, ADM twin fuel pumps and FPCM, G-Force 9" rear and axles, 4.11 gears with Trac-Loc differential, Hotchkis chassis brace, Full treatment of every BMR rear suspension arms complete with rear suspension cradle bushings, and of course, a custom tune via HP Tuners. I've done everything myself (except for the tune which was done by the best LS tuner out here in CO) in my own home garage.

I recently bought HP Tuners (the pro version) for myself, and downloaded my tune from the Vehicle Control Module. I noticed when I opened up the VCM Editor, under "Spark" there are the two spark curve maps - one pair labeled "Low Octane" and the other pair labeled "High Octane".

Now, I KNOW my car will NEVER have low octane gas put in her. I don't take my car to a dealership EVER (obviously). No one but me will EVER drive her. Not no how, not no way.

I had noticed that sometimes, my exhaust pipes would rattle a bit under very specific circumstances. It would sometimes tap the crossmember just a bit - which the knock sensors translate that metallic sound into engine knock - and them immediately go to the "Low Octane Map". I even tried dropping the cross member a bit using spacers, but with the new Hotckis Chassis Brace, the bigger 3" pipes still hit the tabs (not the cross member) every now and then.

So with that all being said, I simply copied the High Octane tables and values, and pasted them into their corresponding Low Octane tables, so both maps now are identical, and are set for "High Octane".

What are your thoughts on this? Am I flirting with disaster, or do you think that I should be ok as long as not a single drop of low octane fuel finds its way into my tank? The difference between the low octane map and the high octane map is astounding - which is why there's such a marked difference in performance that everyone can instantly feel. At some spot, it pulls out as much as 20 degrees of timing (between the modified performance tune I had and the stock low-octane map).

Opinions/thoughts?

HAPPY NEW YEAR!

BLESSINGS!
Sam

Originally Posted by 90503

I like your style...lol...Not sure, but map thing might be the same or similar to what tunes/tuners do....only "problem" for us stock types is the warranty gets voided...good luck...you might be on to something...

Originally Posted by Ace1USMC

Thanks for your response! I thought the same thing about tuners - but what I found is that all the tuners modify just the high octane maps, and leave the low octane maps alone for the "just in case" scenario. And because of that, my car kept going to the low octane map.

On a follow-up note, I took the car out for the first time since doing it last night, and WOW! What a difference! I have been running on the low octane map for a while, and it was such a blast to drive on the big boy map!

Originally Posted by 90503

From what I've seen in this thread, most who have modified and tuned are under the belief that a fuse pull is no longer necessary...You may have dis-proved that theory...lol...

Only other thing as far as what you have done being bad, is that I sort of believe (being stock, basically) is that even with the simple fuse pull, the timing is set too high...and may cause a "knock" from that...but it is short lived as it will "learn down" as needed....

...Pulled these up from a while ago...thought they might be pertinent...enjoy...

[Scott@Bjorn3D]

Originally Posted by SSRS55

So exactly what are you saying here.. it maybe necessary?

Yes

[CRTZL1]

Originally Posted by 90503

...Pulled these up from a while ago...thought they might be pertinent...enjoy...

This is exactly what I was talking about....
So this is why I don't know if I need to do the fuse pull or not...
But I give up trying to get my answer here, I'll be calling Ted Jannetty tomorrow and clear this question once and for all...

[CRTZL1]

Originally Posted by Scott@Bjorn3D

Yes

Some say yes and other say no... calling Ted in the morning, will post my findings after I speak to him...

[90503]

Originally Posted by SSRS55

Some say yes and other say no... calling Ted in the morning, will post my findings after I speak to him...

...Just to add, I've never seen anyone who has had a tune ever say their tuner told them "not" to do a fuse pull...

....Tuned or not, a fuse pull can't hurt anything...it takes about ten minutes to do...and if you are tuned and a fuse pull makes a difference, then you have your answer...

[CRTZL1]

Originally Posted by 90503

...Just to add, I've never seen anyone who has had a tune ever say their tuner told them "not" to do a fuse pull...

....Tuned or not, a fuse pull can't hurt anything...it takes about ten minutes to do...and if you are tuned and a fuse pull makes a difference, then you have your answer...

If I decide to do this and I don't mean to be a pain... what fuses do I need to pull? And is it necessary for me to do the trunk fuse as well??
I have a 2012 auto SS.....
Thanks....

[90503]

Originally Posted by SSRS55

If I decide to do this and I don't mean to be a pain... what fuses do I need to pull? And is it necessary for me to do the trunk fuse as well??
I have a 2012 auto SS.....
Thanks....

I've always done just the fuse #5 and fuse #20 in the fuse box...Others do only the trunk, or trunk and fuse box...Personally I've never done the trunk because I get good results from the fuse box...

...I pull them out right after I've driven it...let it sit six, eight hours...(some claim even fewer hours work) or leave them out overnight for convenience...put them back in, and away you go....

[CRTZL1]

Originally Posted by 90503

I've always done just the fuse #5 and fuse #20 in the fuse box...Others do only the trunk, or trunk and fuse box...Personally I've never done the trunk because I get good results from the fuse box...

...I pull them out right after I've driven it...let it sit six, eight hours...(some claim even fewer hours work) or leave them out overnight for convenience...put them back in, and away you go....

Thanks man!!!!

[BLU DUCE]

Originally Posted by SSRS55

Thanks man!!!!

I have 15,000 miles on my 1SS L99 Auto. Have never pulled the fuses or had a tune & never will get a tune because I don't want to. So don't bother asking why. I get around 17 MPG & use Sport Mode but mostly paddle shift because I like too. But I also have a lot of mods on engine. But come Spring I will do the fuse pull on all 3. Because I want to.

[JD_Alaska]

Anyone know at what octane level it switches to the low octane map?