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

[PQ]

Originally Posted by 2013Ashen2SSRS

OK so I have a dumb question and it may have already been answered...but I live in Wyoming and the highest octane I can get at the moment is 91 octane...is this considered a low octane to where it would effect the engine like 87 octane? Will my car be in limp mode with 91 octane? I have never used anything lower than 91 octane and I am pushing 3000 miles on the 2013. Just wondering if I should pull the fuses to see if it helps boost me any from where I'm already at or give different feel like so many are saying. Oh I am all stock, no mods!!

It's considered high octane.

Originally Posted by techinny

Not exactly sure what you mean, but in order for a circuit to work it has to have power and ground. I do know that if you are doing a continuity test (with the battery unhooked, which is the way it should be done) if you check continuity from the frame (ground) to a fuse that is normally (with the battery hooked up) positive, you will see continuity. Easiest way to explain it---a light bulb has power coming in on one side and ground on the other, the filament completes the circuit and lights up. If you turn the power off, the filament is still completing the circuit, so if you check continuity between ground and the light's switch, you will have continuity but with the resistance of the light bulb.

1. I do not know how or if this info plays a role in this whole thread.

2. If my rambling of what I know about electricity is boring or confusing anyone, I am sorry.

3. If you would like me to stop rambling, please say so.

Well, maybe not junction but I mean like wiring in the house at a light recepticle. Just because you turn off the light using the light switch doesn't mean the wires in the box inside the light recaptacle are not hot. All you did was run a hot wire to a switch and returning to the box and switch it in line. Yet the box (type of junction) still holds juice on the one side of the hot wire. The neutral wire being the one that completes any circuit other than actual switches. Neutral never goes to the switch. Just completes the circuit AT the fixture.

So, if the fuse in the 'Fuse Pull' case were the 'switch' then I'd say you could be on to something. But the ignition is actually the switch.

The ignition being the circuit switch and the fuses on the 'dead' side of the circuit. Only to get power when the circuit is activated. (key turned on)

So the fuse is downstream so to speak.

BUT, that is just explaining what I meant. I doubt we'll get anyone in here that knows if what you are saying is plausible.

[PQ]

Originally Posted by Schofield25

Just curious if there's a reason that I may not know about

Reason for what?

[techinny]

The way you described it sums it up. But like you said, who will say that it's the way it works.

[PQ]

Agreed.

Right now I lean well toward it not working. But admit that it still might work.

Wish I knew.

[Brutal SS]

My butt dyno clearly shows noticable gains!

[hapisok]

Originally Posted by PQ

Unless someone can show how two non-powered fuses can reset the ECU then yes. It was a coincidence with mine. Thought is was the fuses but apparently was my dealers reflash.

So, I don't know what the hell happened with the rest.

just for clarification and not to insult anybody's intelligence, but electricians and electronic technicians are not the same field. although they do share the same basic laws and principles like OHMs law, thats about where they stop. electricians work with automotive, residential or commercial wiring in regards to power distribution, outlets, lighting, HVAC, load centers...etc. electronics is a different field of and or gates, flip flop circuits, timing circuits, comparative circuits, latching circuits...semiconductors (diodes and IC chips), circuit board level components where 1's and 0's thrive. yes, there are some basic comparisons between the two, but you can't simply relate one to the other because you can't without being confused. what makes sense in the electrician world doesn't always make sense or even work in the electronic world.

it all comes down to 1's and 0's...that is how computers work in regards to input and output. whatever signal is holding the ECU to the lower octane table is changed when you pull fuses 5 & 20. its not that the fuses have power, its that they provide a ground and the ground is providing the "latch" to hold the signal in the "low octane" state. once you remove the latch, there are some capacitors that discharge or gates that are removed from IC's & diodes allowing the state to change the ECU to switch back to the high octane tables.

it appears that the fuse pull is part of what is called an "active high" circuit. Both inputs are normally tied to ground (LOW), and the latch is triggered by a momentary HIGH signal on either of the inputs. hope this isn't too confusing...it isn't easy to understand. but its why the fuse pull DOES work.

sorry, its electronics and im not good at explaining it. a circuit speaks a million words and helps to understand things better.

you could compare it to the BSOD (blue screen of death) where the low octane tables are the BSOD and high octane a normal functioning OS. you get a BSOD and your computer will just sit there, not accepting any input from the user. only solution is to turn off/remove power (fuse pull) and reboot the system.

[kfm237]

Originally Posted by hapisok

just for clarification and not to insult anybody's intelligence, but electricians and electronic technicians are not the same field. although they do share the same basic laws and principles like OHMs law, thats about where they stop. electricians work with automotive, residential or commercial wiring in regards to power distribution, outlets, lighting, HVAC, load centers...etc. electronics is a different field of and or gates, flip flop circuits, timing circuits, comparative circuits, latching circuits...semiconductors (diodes and IC chips), circuit board level components where 1's and 0's thrive. yes, there are some basic comparisons between the two, but you can't simply relate one to the other because you can't without being confused. what makes sense in the electrician world doesn't always make sense or even work in the electronic world.

it all comes down to 1's and 0's...that is how computers work in regards to input and output. whatever signal is holding the ECU to the lower octane table is changed when you pull fuses 5 & 20. its not that the fuses have power, its that they provide a ground and the ground is providing the "latch" to hold the signal in the "low octane" state. once you remove the latch, there are some capacitors that discharge or gates that are removed from IC's & diodes allowing the state to change the ECU to switch back to the high octane tables.

it appears that the fuse pull is part of what is called an "active high" circuit. Both inputs are normally tied to ground (LOW), and the latch is triggered by a momentary HIGH signal on either of the inputs. hope this isn't too confusing...it isn't easy to understand. but its why the fuse pull DOES work.

sorry, its electronics and im not good at explaining it. a circuit speaks a million words and helps to understand things better.

you could compare it to the BSOD (blue screen of death) where the low octane tables are the BSOD and high octane a normal functioning OS. you get a BSOD and your computer will just sit there, not accepting any input from the user. only solution is to turn off/remove power (fuse pull) and reboot the system.

Then.. Does it truly matter if the 5 & 20 fuses are pulled out for a few seconds or overnight as most have done???

[Brutal SS]

[hapisok]

Originally Posted by kfm237

Then.. Does it truly matter if the 5 & 20 fuses are pulled out for a few seconds or overnight as most have done???

thats a good question. if it is simply pulling the fuses resets it or if there is a capacitive discharge time is still unknown.

[PQ]

Originally Posted by hapisok

just for clarification and not to insult anybody's intelligence, but electricians and electronic technicians are not the same field. although they do share the same basic laws and principles like OHMs law, thats about where they stop. electricians work with automotive, residential or commercial wiring in regards to power distribution, outlets, lighting, HVAC, load centers...etc. electronics is a different field of and or gates, flip flop circuits, timing circuits, comparative circuits, latching circuits...semiconductors (diodes and IC chips), circuit board level components where 1's and 0's thrive. yes, there are some basic comparisons between the two, but you can't simply relate one to the other because you can't without being confused. what makes sense in the electrician world doesn't always make sense or even work in the electronic world.

it all comes down to 1's and 0's...that is how computers work in regards to input and output. whatever signal is holding the ECU to the lower octane table is changed when you pull fuses 5 & 20. its not that the fuses have power, its that they provide a ground and the ground is providing the "latch" to hold the signal in the "low octane" state. once you remove the latch, there are some capacitors that discharge or gates that are removed from IC's & diodes allowing the state to change the ECU to switch back to the high octane tables.

it appears that the fuse pull is part of what is called an "active high" circuit. Both inputs are normally tied to ground (LOW), and the latch is triggered by a momentary HIGH signal on either of the inputs. hope this isn't too confusing...it isn't easy to understand. but its why the fuse pull DOES work.

sorry, its electronics and im not good at explaining it. a circuit speaks a million words and helps to understand things better.

you could compare it to the BSOD (blue screen of death) where the low octane tables are the BSOD and high octane a normal functioning OS. you get a BSOD and your computer will just sit there, not accepting any input from the user. only solution is to turn off/remove power (fuse pull) and reboot the system.

Originally Posted by kfm237

Then.. Does it truly matter if the 5 & 20 fuses are pulled out for a few seconds or overnight as most have done???

Originally Posted by hapisok

thats a good question. if it is simply pulling the fuses resets it or if there is a capacitive discharge time is still unknown.

Very interesting. VERY interesting.

Last night I took the start capasitor off of my home Heating/AirC fan and tested it. I used a regular multi-meter and seemed to test good. (discharging the power and then starting from 0.00 and raising power as it held the charge from the battery in the multi-meter until it just read infinity.

(at least I think that's a good test)

BUT, If one of those fuses held the ground or cross as far as discharging a capasitor so to speak then it's certainly plausible for it to work while showing no power to the fuse.

I wondered that myself. Any way to find out?

[E.T.]

Why would GM put this fuse pull "trick" in a TSB if it didn't work?

[slick rick]

People are still arguing over whether this works or not?

[VQ35DE]

Just pulled all three fuses so there will be no doubt. Pulled 5 and 20 under hood and 10 in the trunk on my 2010. After doing it I can say that it is easy to get to the trunk fuse and only took about 5 minutes to get to the fuse and another 5 minutes to put it back together ! It was not hard to do at all. No joke ! I have not even started the car yet, just wanted to report that the trunk fuse pull is not a difficult task . If I can do it, then anyone can !

[PQ]

Originally Posted by E.T.

Why would GM put this fuse pull "trick" in a TSB if it didn't work?

Well in the GM doc it's only one of the engine compartment fuses and the trunk fuse.

Originally Posted by slick rick

People are still arguing over whether this works or not?

Not really. We know the bogging problem is fixed with a fuse pull but just which fuses and why are the problem. There is no power to the engine compartment fuses when the key is off. So we don't know how it can matter if they are pulled.