stock 92 civic vx vtec question?

[97-civic-ex]

I give up. You are going based on feel, not on design, test, and understanding of how it work. We have all tried to explain it to you, but you just wont take the time to understand the design so you can corrolate it with the response. Good luck in your endeavour.

[83gs1100g]

Originally Posted by 97-civic-ex

I give up. You are going based on feel, not on design, test, and understanding of how it work. We have all tried to explain it to you, but you just wont take the time to understand the design so you can corrolate it with the response. Good luck in your endeavour.

if anyone truly understands how this works then would be able to answer my questions?

i will ask again. if it goes to 12v when engaging L/B then how can it already be in 12v?

[97-civic-ex]

LISTEN CLOSELY

Lean burn does not put it in 12V!!!!!! It starts in 12V with normal operation and 14.7:1 AFR,... the ecu looks for the proper temp, the proper engine load,.. the proper RPM,... and a few other little odds and ends and then it decided everything is good to enter lean burn at which time it will ONLY and I repeat ONLY change from 14.7:1 AFR to 22:1 maybe even 26:1 AFR,... that is it. That is all lean burn does, that is all the ecu will do. When you step on the pedal more,.. increasing the engine load, it will kick you back down to 14.7:1 taking you off lean burn. All the above can and more than likely will be done while in 12V mode and never entering 16V mode.

If you really really want to learn for yourself, do tests and experiments to satisfy yourself. Follow the fuelly thread you posted and install a vtec light. By installing a light it will eliminate all doubt from your head and you will realize what it is that you are feeling,... if lean burn mode OR vtec engagement/disengagement. Better yet after you install the vtec light install an O2 sensor gauge and when it stays all the way on lean for a few seconds, more than likely you are in lean burn mode. Again, the 2 don't happen at the same time. Stop relying on shift light,... its a shift light, not a lean burn indicator, not a vtec indicator,... just a shift light.

[83gs1100g]

Originally Posted by 97-civic-ex

LISTEN CLOSELY

Lean burn does not put it in 12V!!!!!! It starts in 12V with normal operation and 14.7:1 AFR,... the ecu looks for the proper temp, the proper engine load,.. the proper RPM,... and a few other little odds and ends and then it decided everything is good to enter lean burn at which time it will ONLY and I repeat ONLY change from 14.7:1 AFR to 22:1 maybe even 26:1 AFR,... that is it. That is all lean burn does, that is all the ecu will do. When you step on the pedal more,.. increasing the engine load, it will kick you back down to 14.7:1 taking you off lean burn. All the above can and more than likely will be done while in 12V mode and never entering 16V mode.

If you really really want to learn for yourself, do tests and experiments to satisfy yourself. Follow the fuelly thread you posted and install a vtec light. By installing a light it will eliminate all doubt from your head and you will realize what it is that you are feeling,... if lean burn mode OR vtec engagement/disengagement. Better yet after you install the vtec light install an O2 sensor gauge and when it stays all the way on lean for a few seconds, more than likely you are in lean burn mode. Again, the 2 don't happen at the same time. Stop relying on shift light,... its a shift light, not a lean burn indicator, not a vtec indicator,... just a shift light.

thanks for the reply. i understand what you posted and agree 100%. ok now were gettin somewhere. so when motor goes into L/B if its all ready in 12v what is happening with the loss in power when it goes to L/B? something has to change to feel the drop in power? some have posted that it goes to 12v when going to L/B? so if this isnt true then whats happening to cause the loss in power when it goes to L/B?

again thanks for the reply.

[Baltothewolf]

Originally Posted by 83gs1100g

thanks for the reply. i understand what you posted and agree 100%. ok now were gettin somewhere. so when motor goes into L/B if its all ready in 12v what is happening with the loss in power when it goes to L/B? something has to change to feel the drop in power? some have posted that it goes to 12v when going to L/B? so if this isnt true then whats happening to cause the loss in power when it goes to L/B?

again thanks for the reply.

Now I can answer that, the motor is leaning out, there is less fuel being burned therefore less power, take your own body for example, at high altitude when the oxygen is more 'lean' it's harder to breathe. Same thing.

[97-civic-ex]

Oh and if you think you are going into lean burn when the shift light comes on, you really don't understand lean burn. Depending on your driving habits, the shift light will more than likely come on above the lean burns RPM range of operation.

[97-civic-ex]

Originally Posted by 83gs1100g

what is happening with the loss in power when it goes to L/B? something has to change to feel the drop in power?

you didn't listen closely:
lean burn does the follpwing

Originally Posted by 97-civic-ex

change from 14.7:1 AFR to 22:1 maybe even 26:1 AFR,... that is it.

AFR = Air to fuel Ratio
i.e.
14.7 air molecules to every 1 fuel molecule


Lean burn
22:1 AFR
22 air molecules to 1 fuel molecule

the way this is achieved is by reducing the fuel into the combustion chamber and keeping the air delivery the same,... i.e. making the AFR more lean

This is the loss in power,... the idea is you stay in this mode to coast and maintain the speed while using less fuel. If you must speed up,.. it more than likely will kick you out of lean burn giving you a little more power. Notice again how the above can and more than liklely only happen in 12V mode and never entering 16V mode.

[83gs1100g]

Originally Posted by Baltothewolf

Now I can answer that, the motor is leaning out, there is less fuel being burned therefore less power, take your own body for example, at high altitude when the oxygen is more 'lean' it's harder to breathe. Same thing.

correct. this is what happens. the fuel gets cut back giving better mpg based on being in 12v.
so knowing this is there 3 stages of fuel mapping ie... 12v non-L/B, 12v L/B, and 16v?
cause if i disconnect my o2 sensor and drive as normal it feels as though its in 16v all the time. when i hit the crossover rpm you feel NO increase in power? yes i know its going to be very minimal power increase when this happens! but you should feel something. this is why i question how its described. this is why i question all this? to me its the same process feel if i maintain just barely enough throttle to keep it from L/B when i hit the crossover rpm there is no increase(slight) in power.

thanks all for posting!!!!

[97-civic-ex]

When you disconnect the O2 sensor it will never kick in vtec because you get a check engine light and you have now made the ecu run the motor blind.
This puts it in limp mode which will, for safety reason, now run the engine at a safe AFR.

It will be somewhere around 12:1 AFR which will feel like slightly more power because it is running rich(safe).

Your method of testing is too random and since you don't understand it well, you are making bad assumptions.


Start learning about open loop and closed loop and you will see that your assumptions of different mapping is not as easy as you posted. Although somewhat true it utilizes 3 different maps for those 3 different modes, while in closed loop it uses the maps as a starting point and relies on the O2 sensor for fine tuning to maintain the proper AFR. Without the O2 sensor it will have to fall back into a safe zone and protect the engine from a catastrophic outcome.

[pgfpro]

Originally Posted by 83gs1100g

correct. this is what happens. the fuel gets cut back giving better mpg based on being in 12v.
so knowing this is there 3 stages of fuel mapping ie... 12v non-L/B, 12v L/B, and 16v?
cause if i disconnect my o2 sensor and drive as normal it feels as though its in 16v all the time. when i hit the crossover rpm you feel NO increase in power? yes i know its going to be very minimal power increase when this happens! but you should feel something. this is why i question how its described. this is why i question all this? to me its the same process feel if i maintain just barely enough throttle to keep it from L/B when i hit the crossover rpm there is no increase(slight) in power.

thanks all for posting!!!!

12v non-L/B
12v L/B if all parameters are meet
16v non-L/B (there is no 16v L/B)