I removed all my air pump equipment and I'd like to know how long it takes for a 1 wire o2 sensor to warm up. Just give me an aproximate time. Let's say I was running rich in open loop. Does this help?
Now if it goes into closed loop too early (before o2 warms up), is the car going to run lean or rich and how 'off' is the sensor as the temp changes?

 

I don't know what the baseline is for other cars(lean or rich), but I just pulled a reading 15 minutes ago and mine was running really lean at idle. I've noticed on several other trips that before the car got into closed loop it was always running lean (BLM~150). I've got a real rough idle and that might be the problem for me (need to tune it out).

Doesn't help (I think) but it's what I've seen.

Sparks a flyin'

 

You definatly need to adjust that. 150 isn't good for the motor, when in open loop you're probably running way lean! not to mension your IAC will open up to try and adjust for the crappy idle...this will just make things more lean. Definatly bump up your injector constant or something. It's better to run below 128 (rich) than above.
I just wish I could figure out this darn 4 wire 02 sensor. I have it but didn't install it because I was just trying to get my car to RUN. It's an easy install but I think I might be running into problems when tuning in closed loop because the o2 sensor isn't warming up. I'm thinking that it's making me run lean because that's what it feels like.
Grumpy, I know you know this one :-). Don't you like my technical questions

 

I installed an extra O2 sensor when I installed my full length headers and connected that to an A/F meeter (home built)

I used a one wire O2 sensor and it is located at the collector. The meter comes alive after 30 seconds or so. Heat up time is not a problem. When I let it idle for a while it gets too cold, so I will replace it with a heated one later on. I think that is because it is so far from the exhaust ports.

I think that the air pump is used to heat up the cat, not the O2 sensor.

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Jonas Bylund

 

JP,

I had just burnt a chip to run in my car with the injector constant changed for that reason. I was going out to hook my laptop up and make some runs, when the computer fell to the concrete and shattered the screen and fubar'ed the HD. So, I haven't had a chance to check the changes I made. Have a new laptop now, so I'm going to attack this problem.

Sparks a flyin'

 

Actually from what I've gathered, the air pump is used to heat up both the 02 sensor and the cat. That is why we have a diverter switch on the passengers side. At startup the air is directed to the headers before the o2 sensor. This extra oxygen burns and heats up the sensor as long as you're running slightly rich during startup. If you're lean then it doesn't do much good. Then after the car goes into closed loop the air switch is directed only to the cat converter to help burn off the extra hydrocarbons before they go down the intermediate pipe. This is information I've gathered from reading the board so I'm not sure it's all correct but it doesn't make sence. The vettes had a heated o2 sensor or didn't they? Did the older crossfire vettes have a 3 wire or 1 wire? Anyways, the 3 and 4 wire heated o2 sensors make them more accurate and let the computer go into (and stay in) closed loop from what I've gathered. That is...as long as you're manifold pressure is still strong and all the other requirements are met.
I have a 4 wire sitting here but I haven't figured out which wire goes where. I got it new from a take off part, I think the link is:
http://www.goautocenter.com/super_deals.htm
For $20 I couldn't pass it up.
Heck, look at the price of the other sensors!
Good deals
Now if somebody could tell me where to find the darn instructions as to which wire is for what .

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, Jon (350 TBI!)
91 Red My website

 

I am running a little rich with SVO 24# injectors, and it takes me about 1 minute to go into closed loop. I dont know how much climate affects it, but i am in southern california.

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1989 IROC-Z 5.7L
NOS 5151 150HP kit
ProBuilt 700R4, PI Vigilante 2800 stall lockup
Baer Brakes 12" Sport System

 

You cannot take the O2 sensor's (one wire, unheated style) lean readings during a cold start as a true reading of where the air fuel ratio is at. The sensor needs to warm up, as discussed above. And it just so happens that installing headers and removing emissions control devices (ie. A.I.R. system and catalytic converter) extends this warm up time even further (this inefficient design is what brought about the heated O2 sensor which heats up fast and is able to get the system into closed loop sooner which =, among other things, cleaner emissions and better idle quality).

This also means that installing an O2 sensor (one wire, unheated style) for monitoring the air fuel ratio too far from the engine is not very useful. It will tend to be reading inaccurate - likely not ever reading accurate since it is so far downstream from the source of heat (the engine) that it needs to stay hot enough to read accurately.... The bottom line is that the O2 sensor's on our cars are very sensitive to how far away from the engine they are because they need to stay hot enough too accurately read the air fuel ratio (mixture) that the engine is running at....

And don't worry about what the BLMs are on a cold start either; they are not reflective of the air fuel ratio until the system goes into closed loop... (see above)

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1987 GTA L98 MD8
355, TFS Heads, LT4 Hot Cam
My GTA

The Minnesota F-body Club

 

I programmed my current eprom to go into closed loop pretty quick and I know this is stupid...now...after the fact. I'm just curious, am I going to be running on the lean side or rich side if I'm at '128'?

 

The stock O2 sensor on my Corvette (84) is a one wire.

This is where I put my O2 sensor. The other pipe is for crankcase ventilation.




You can measure the wires and figure it out ...

1 wire: sensor and housing is ground.

2 wire: sensor and ground. Ground wire is shorted to the housing. Sensor wire should have very high ohm to housing when cold.

3 wire: Usually two wires have the same color and they are for heating. Connect one to 12V and the other to ground. Polartity does not matter. Third wire is sensor. Housing is ground. Sensor should have very high ohm to housing when cold. Lower resistance between the heater wires. The heater wires should have no connection to housing or sensor wire.

4 wire: same as 3 wire but with a ground wire that is shorted to the housing.


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Jonas Bylund

 

It takes longer for the coolant to get to temp then the O2 to heat on every car I've worked on.

Heated 3 wire that I'm using takes about 30 to start to flicker, and the WB 45 secs. I have the CTS enable (for closed loop) turned down to 90dF and the O2 is still always ready first. BTW, I use an 85dF temp endable for the TCC.

 

It doesn't hurt the motor to run at other then 128s. Just that your wasting the ability of the BL, and slewing all the corrections in the ecm to the extremes, which can leave you with tip in stumbles, etc.. If you runniing a BL of 160 and Int of 128 your still at 14.7:1 (well as they've told us)

 

Does both.
Smog pump promotes afterburning in the exhuast. Meaning they TRY to have an excess of O2 around so any unburnt hydrocarbons further react.

 

I relocated my O2 sensor back about 5' from the oem location, no problem.
there is a time transist time in the code for how long after a change the O2 should respond, IF you found a problem with the O2 being relocated that MIGHT be tampered with. But, I think mine is the worst case sensario, going from pre turbo to way the heck downstream, and everything is fine. At lean cruise the O2 mv dropped like 15mv, hardly enough to count

 

Might have something to do with it being a Turbo'd engine. Dunno. I have seen instances where installing headers that move the O2 farther downstream then the OEM location and whatnot making the O2s get "lazy" on N/A cars.....

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1987 GTA L98 MD8
355, TFS Heads, LT4 Hot Cam
My GTA

The Minnesota F-body Club