yea, the main reason i went with hpt was because it was easy to use, and no install required.... as time goes on, capabilities increase, plus whats there already is more then enough for most.... price is nice too
even though megasquirt (which is what jcavi was referring to i think) is a good price as well
|Forged 8.9:1 Wiseco Pistons|Forged Eagle Rods|HPTuners|60trim|Tial Wastegate|
|Precision Intercooler|2.5" Exhaust|2.5" Charge Pipes|630CC Mototron Injectors|
|Stock: Fuel Pump, Transmission, Manifold, TB, Head, Head Gasket, Ignition, Suspension...|
Quote:
Acer Online
Friday, July 07, 2006 1:15 PM
Is it possible to run whatever voltage the stock o2 sensor needs to think it is at stoich and then tune using only the wideband?
why? you should always tune using only the wideband...
answer the question 'why would you ever need to do that?"
i'm curious to see the reasoning.
Quote:
The stock one is just so sperattic that it seems to me that it would cause more harm then good
...and what does this mean? I don't know where you're getting at with this post/ question
I think you need a lesson in the basics of tuning.
When you are in a partial throttle situation (read: non WOT / Power Enrichment, or PE), the computer constnatly adapts injector pulsewidth for stoichiometric air/ fuel ratio. because if you're in a non PE situation, ideally you want the best gas mileage you can get right? right.
Now when you mash the throttle, most ecus go into whats called 'open loop' (aka PE), which ignores the stock O2 sensor, and goes to a preprogrammed air/ fuel ratio table and spark advance table for maximum power.
Stock ecotecs however, don't go into this programming until 6200 RPM, but with HPT you can set that to 0rpm, so that whenever you mash the gas pedal, you go into PE which is what you want.
When you're in PE, your air fuel ration is more constant which will be reflected on your narrow band O2 gauge (although they are VERY inaccurate due to the 0-1.250V range or whatever it is). A wideband O2 sensor/ and gauge is the only way to properly tune fuel whether it be in PE or normal mode.
As was said, you can make ur wideband talk to the factory ecu, but in all honesty running two sensors is easiest even tho you're probably trying to avoid welding on an o2 sensor bung, aren't you?
if ur getting problems with fuel, consult this
thread, it shows you how to turn PE on for the ecotec ecu (this is what you want)
hey!! Thanks for that info... although i knew most of it, im glad you chimed in
give me a reason to bring this one back, because resetting my computer fixed the problem for about 10 minutes and i came upstairs to post it worked, and then after driving it for a day, things are back to normal
I know that then i am in closed loop the pcm uses fuel trims to add or take away fuel as needed to attain the magical 14.7 afr.... my problem is that my wideband reads 13.0 at idle and my fuel trims are are low as hell.... which tells me that my pcm THINKS it is at 14.7 because its not trying to do anything to change it...
I wanted to run the signal from the wideband to the pcm instead of the stock o2 sensor because it is more accurate and more consistant.... AEM recommends getting rid of the stock o2 sensor and tuning with the wideband with their standalone... i want my pcm to see the 13 that my wideband see's and not whatever the stock o2 sensor is seeing....
from the research i have done and brainstorming i have done with my friend i have deducted that it could be an exhaust leak that is making the stock o2 sensor think that there is not enough fuel and adding more fuel to compensate for what is not reaching the stock sensor and the wide band picks up the "actual" a/f ratio which is around 13.0 usually. I am not sure if this is possible however since the wideband is located after the stock o2 sensor and technically should see the same or less then the stock o2 sensor... maybe the only way my theory could be correct is if the wideband came first and then the stock o2 sensor and there was a leak in between... i dont know... but my stock o2 sensor is within 3 inches from the flange on the turbo and the wideband is at the end of the exhaust (2.5" open dump)
if there was a way to get the stock pcm to see a wideband i would love it!! or maybe a way to tell hptuners to tune af;s based on the input signal from the wideband :-o that woudl be awesome!! lol... i dont think its possible though
ANY INPUT at all is appreciated greatly!!
P.S. Damn GM and there 1.25 range instead of 0-1V
that would have made my life easier... i need a device that takes the 0-XV signal and translates it to 1.250V's giving me the input the stock pcm is looking for....
Another P.S. I am getting a new exhaust soon, i will have more info then (i.e. whether or not it is a possible exhaust leak problem for sure)... thanks
|Forged 8.9:1 Wiseco Pistons|Forged Eagle Rods|HPTuners|60trim|Tial Wastegate|
|Precision Intercooler|2.5" Exhaust|2.5" Charge Pipes|630CC Mototron Injectors|
|Stock: Fuel Pump, Transmission, Manifold, TB, Head, Head Gasket, Ignition, Suspension...|
Quote:
I know that then i am in closed loop the pcm uses fuel trims to add or take away fuel as needed to attain the magical 14.7 afr.... my problem is that my wideband reads 13.0 at idle and my fuel trims are are low as hell.... which tells me that my pcm THINKS it is at 14.7 because its not trying to do anything to change it...
What do you mean by "low fuel trims"?
Do you know how the fuel trims work? I think that is confusing you, because what you said is incorrect.
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well i was just logging and the fuel trims are between 2 and -2 all the time, long term and short term...
from what i understand the pcm determines how much it needs to add or take away to get to 14.7 and over time it builds a long term fuel trim in an attempt to keep the short term one as close to zero as possible.... i might be wrong, that deduction is based completely off my friends input and other peoples posts, lol...
|Forged 8.9:1 Wiseco Pistons|Forged Eagle Rods|HPTuners|60trim|Tial Wastegate|
|Precision Intercooler|2.5" Exhaust|2.5" Charge Pipes|630CC Mototron Injectors|
|Stock: Fuel Pump, Transmission, Manifold, TB, Head, Head Gasket, Ignition, Suspension...|
Basically fuel trims are this..
The short term fuel trim adjust fuel based on what is going on right now. If the trim is one way or the other (positive or negative), then the ecu changes the long term trim in that direction and starts the process over again.
Positive trims mean that the ECU is adding fuel, thinking the system is too lean.
Negative trims mean that the ECU is removing fuel, thinking the system is too rich.
So, based on what you said, the ECU is doing the correct thing. Your system is showing 13:1, it wants 14.7:1, so its removing fuel (trims being low I'm assuming they are negative). So they ECU KNOWS its not at 14.7 and its adjusting correctly.
And you need to get it out of your head that the O2 feedback of a constant AFR means a better running car. The sensor bouncing back and forth is the ECU adjusting the fuel as the trims go, and its making the sensor switch so it can tell if the sensor is working correctly or not. If you watch your short term fuel trims, they go up and down very fast, almost in sync with the O2 sensor. Well its making the sensor switch.
It also allows the system to run a little lean over time on the highway for fuel economy.
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fuel trims are always below 2 and above -2 and USUALLY close to 0.XX.
there is not much adjusting going on....
i understand running a constant to the ecu doesnt mean the car is running fine, i just thought that if the pcm could see what my wideband sees it would know that fuel trims need to be at a really negative number to take enough fuel away for my car to idle at 14.7 and cruise at 14.7-15.1... i think if the pcm knew the afr was 13.0 my fuel trims would be very very negative numbers to take away fuel, and it would not hover so closely to 0 as if it is done adjusting
im going to log tomorrow and post the log for you to see what i mean exactly, ima figure out how to get my wideband hooked up so i can log it at the same time to show what i mean exactly...
thanks for your presistence in my seemingly ignorant posts... i am tryin to be clear
|Forged 8.9:1 Wiseco Pistons|Forged Eagle Rods|HPTuners|60trim|Tial Wastegate|
|Precision Intercooler|2.5" Exhaust|2.5" Charge Pipes|630CC Mototron Injectors|
|Stock: Fuel Pump, Transmission, Manifold, TB, Head, Head Gasket, Ignition, Suspension...|
I do get what your saying, but you seem to think that the stock O2 sensor is not accurate at reading stoich, when in fact it is EXTREMELY accurate in reading stoich, it is not accurate in reading anything else. You also have to remember that when you are idling cold, the system will be running rich. Mine idles when I start it up at 12:1.
Also, a 1.7:1 error in the AFR does not mean your fuel trims will go off the map to get the AFR back in line. Even short term fuel trims are trims over time, they are not instant.
If you think you are idling too rich, you need to adjust your idle VE table to bring your AFR back to where you want it. This is especially evident when you first start up the vehicle and before the system enters closed loop.
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