Entering Closed loop faster with $A1

[tkoforpresident]

This might be a bit of a long read so stick with me guys. After installing a radical cam/bigger injectors and whatnot into my firebird and having Ben help me tune the beast up (and rather nicely I might add) via a 7727 pcm and $a1 mask the only issue remaining is the initial cold start up. Sometimes it will stall out right away (on the first try) and I think maybe we can fix that in the tune, or at least try, but that's not whats on my mind right now. The fact is that until it enters closed loop it runs pretty rich and has the chance of stalling out at any stoplight until that point. Now... once it's in closed loop it runs like a top and I can almost never recall it stalling out ONE SINGLE TIME in closed loop. Therefore, i've resolved to get to closed loop sooner.

Now, from what I understand there are certain points that need to be attained to enter closed loop, the first and most important being a viable signal from the o2 sensor to the PCM. With the single wire o2 sensor that i have now, i'm sure it takes a while to heat up and start giving something the pcm can use. So my first thought is to take a 4 wire o2 sensor (i've seen write ups on this before) and replace it with the current single wire. Now my car has two sensors (one in each header) but since we switched to obd-1 only ONE of those sensors is doing anything. John has told me that it is the RIGHT sensor being used (which i can assume is the drivers side?) but i can easily check once i'm in tuner pro or as Robert pointed out to me once by using a multimeter and checking voltage levels at key on.

That being said, one 4 wire sensor won't break the bank instead of having to buy two or more. And this will be a good start in attaining closed loop quicker (and in the proper manner i.e. not cheating, more on that in a second) but the question i need answered as far as this is concerned is WHICH O2 SENSOR SHOULD I BUY? I have no idea which one will be the best one to buy. Maybe any from a 3x00 motor? Any thoughts on that ?

Now, from what i've read the heated o2 sensors can start giving signals within seconds! But to enter closed loop mode other things need to be met such as a minimum run time based off of Coolant temperature X at startup, and just Coolant temp in general.

A fellow offered up a solution to me that involved putting a resistor into the coolant temp sensor wiring which when switched on would trick the computer into seeing ~ 150* F but my thoughts are that rather than TRICK the pcm into thinking it's at a higher temperature, why not just LOWER the paramaters in the .bin using TP?

I mean that is a viable option isn't it? With the heated o2 sensor installed and the prerequisites for closed loop scaled down to match the faster rate of the o2 signal am i wrong to think that i could acquire closed loop almost within seconds of startup?


What do you guys think of this? Is there something i'm forgetting? Is this feesible?

thanks,

max

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[SappySE107]

No tricking, we can make it enter closed loop faster without a doubt. There are 3 timers based on startup coolant temp. WIth the heated O2, closed loop can be enabled sooner. It really should be able to be tuned to not stall in open loop.

[tkoforpresident]

Great, I'm glad to hear that.

But we can agree that the heated o2 is a necessity then for achieving this.

Now i just need to find out which one will work for me.

Stalling issue aside, I'd like to get into closed loop waay sooner than what it currently does.

[tkoforpresident]

So a heated 02 needs a 12V source that is on only when the vehicle is running. Any thoughts on what i can tap into? Most of the sensors are 5v so that takes those out of the equation. It's too bad the sensor on the passenger side isn't used (still waiting for John to confirm that) since there is a common ground right on the passenger side fender.

Someone linked me to a viable 02 sensor for this swap once but i've since lost it, though i do seem to remember it was around 42$ for it, which I think is a reasonable price to pay for what it's going to do. These cars just run so much better once they've hit closed loop.

[bszopi]

Here is the old article. Figured I'd transfer it over for you. This was written by a guy who put a 3400 into a pre-3x00 vehicle, but the basics should work for you. As far as what sensor to get, just pick out an 3x00 powered vehicle, and get the front (primary) O2 sensor.

[bszopi]

Here is the old article. Figured I'd transfer it over for you. This was written by a guy who put a 3400 into a pre-3x00 vehicle, but the basics should work for you. As far as what sensor to get, just pick out an 3x00 powered vehicle, and get the front (primary) O2 sensor.

http://60degreev6.com/forum/content....Sensor-Install

[tkoforpresident]

Thanks Brad. Now I know which sensor to get. The only thing still hazy is where to tap into for 12V. In the article (that's the one I found btw, but on a different site i think) he taps into a wire behind the alternator but if the working o2 sensor is on the drivers side I'd be hard pressed to run a wire all the way over to the alternator. Just looking for a better option, that's all. The fuse box is right there with all the wires running into it, I just need to pick one that works.

thanks!

[tkoforpresident]

would it work if i used the 12V (red) junction box on the passenger side fender? That might give 12V power even with "key-on" but would that really hurt the o2 sensor? In fact it might help to warm it up before even starting the car. Then again, is that junction box 12V ONLY WHEN KEY-ON and not when running? Can't have that... I need clarification.


the fuse box is pretty close on the drivers side. Perhaps i could run one of these into an extra 12V slot:

[Superdave]

i've used the radio circuit before.. it works just fine.

any 4 wire 02 for a 3x00 car or even a 3 wire from a 3.4 DOHC. Ben is right, it's just 3 different timers and then there are min coolant temps to enable those timers.


On a cold start i set mine to 30 sec, 20 for warm and 10 for hot. One thing Ben can look at is the open loop commanded AFR tables, but with the short timers you won't have to worry about that for very long.

[tkoforpresident]

also, is there a difference between a 3 wire and 4 wire heated o2 sensor? I'm assuming they just combine the two grounds into one?