Hi, last year I installed a 93 LT1 in my 89 RS, this engine needs 2 oxygen sensors, I was able to plug one of the two, not both, reason being that I didn't want to drill holes in my headers. The one I installed is on the y-pipe.

Can I plug the second oxygen sensor connector one on the one witch is already installed ??? like spliting the cable in two ????

 

come'on people, answer me !!!!!

 

should work i would think. The comp might have some issues though i dunno. Technically theres nothing wrong with that but i dont know how the computers gonna like having it's terminals bridged like that. At any rate, i'd give it a shot. Even if it doesnt work it shouldnt break anything. (but dont come looking for me if it does )

 

My biggest issue is actually of bridging those 2 cable, I don't want to blow up the ECM. I'll try it , is it hard to built a oxygen sensor emulator .

Thanks

 

the little wire only puts out 1 volt or less, depending on the O2 readings in the exhaust if you splice it down the middle, and hook it up to the ECM the ECM will just think that both sides of the engine are exactly the same air/fuel ratio, which will do 2 things:
#1: save you the cost of another O2 sensor
#2: Air/fuel metering will not be NEAR as precise as it normally would. the 2 O2 sensor setup is much more effective, as 1 cylinder may be a little leaner on the left side of the engine, or somthing, but when mixed with the other side, appears ok. just keep your plugs clean, thats all

 

Kintal0n is correct. You no longer will be "averaging" the 2 sides of the engine. You can connect both wires to the one O2 sensor. Just use a metal connector and some heat shrink. Of course a 1 wire universal O2 sensor is only $19.00 and someone could weld the bunge in for less than $10.00 on a good day. Then you won't run the risk of running one side lean or rich. Depends on where your current O2 sensor is. If it is downstream where the gases mix it isn't that big a deal. If they are more upstream and reading from closer to the exhaust port then you are going to get an unbalanced reading. Where it is located is important because the ECM expects to receive a signal calibrated for that location.

 

Ok well I got one O2 sensor on my ypipe witch is the original location of the 02 sensor they other motor had and one was on the driver side manifold, I installed headman headers and I wasn't able to install another O2 there...

So you're telling me it would be better if I install one near there also ??? like on the headers collector ??



Can it damage my engine if I do what you said and just plug the other wire to the only O2 sensor I have ???

Can it be why my Lt1 was doing only 160 miles/tank ???

 

The lack of the manifold 02 sensor will make the car think the mixture is lean. The ECM will compensate by richening the mixture which will lead to fouled plugs, poor combustion, fouled valve seats etc. Unless, when the computer senses the the lack of signal from the manifold O2 sensor it's logic stops averaging the two and changes to sense the y-pipe sensor logic only. That I don't know. Too rich is better than too lean. If the car runs too lean then you'll burn a piston or score the cylinder walls. The only other bad thing about too rich is that you can burn an exhaust valve due to post-combustion of unburned fuel as it leaves the cylinder and enters the header. Hope this helps!! Good Luck!! Oh, I would add the 02 sensor to the header if it were me.

Just reread your post. If you are getting poor gas mileage then it is still averaging the 2 sensors (although one is missing) and the car is running too rich. Hence, the poor mileage. It's using too much gas per combustion cycle.

 

thanks

 

Matt i also have the 93 computer in my 86 TA with a 96 LT4 6 speed. the 93 computer requires 2 oxygen sensors , if both sensors are not connected it will go into a default mode hence your bad gas mileage. you can install a oxygen sensor in the y-pipe just after the collector flange. the weld on bungs are about 10 dollars. you should be showing a trouble code for the right bank o2 sensor. also connecting the two sensors together with a splice thats not the way to fix the problem . look at your wire harness and you will see that it has 2 connections at the ecm hope this helps .

 

REMEMBER the farther away from the heads the colder your exhaust is, and O2 sensors NEED to be at LEAST 650* to work properly, TOO COLD an O2 sensor will read VERY WRONG!
It is OK to put the O2 sensor in the HEADER, it actually gives much more precise readings, it can sense each exhaust "puff" as opposed to the Y-pipes "mush" of gasses, and the computer can act fast enough to compensate for each "puff" in fact it compensates 250+ times per second I am told.... possibly more i dont remember...
If i was in your position i would invest a few bucks (okay, $40 +) in a Cool looking Auto-Meter Stoichiometry guage (air/fuel) and hook it to your O2 sensor. this will tell you exactly what your computer is seeing...
then if your Guage says LEAN and your exhaust is spitting black smoke, then you know the problem isnt the Computer, its the O2 sensor. If the guage is reading RICH and your headers are red hot, you know its the computer. etc etc etc... those guages tell ALOT about whats going on in the combustion chambers....

 

I could be wrong but the stock sensors aren't accurate enough for an a/f guage to be of much use. if you hook up a scanner to your ECM when the car is running in closed loop, you will see the oxygen sensor voltage bounce around from .1 to .8 volts. if you hook an a/f guage to it, the guage will just go back and forth a ton and i don't know if the readings will really help much.

 

ok well thanks alot about the info for the 650 degree... now I understand better what it does, not that I didn't understand anything of it , but yes, you're right about the temperature. It will make a major diferrence in the reading ... I will try to install another O2 sensor near the headers flenge ... so it should be reading OK.

 

All O2 Sensors are the Same, All fuel Injected cars mixtures "BOUNCE" back and forth real fast because the computer reacts so fast to a air/fuel change and modifies the on-time of the injectors that it appears to "bounce" this is NORMAL for most cars, even non fuel injected ones especially at idle. at WOT it should show green and if it doesnt somthing is wrong. At cruise it should bounce a little but stay mostly red / near red. if it doesnt, somthing is wrong. The guages help ALOT they tell you what the computer is seeing. just cause the O2 sensor is bouncy doesnt mean it wont help, it just means the computer is doing its job. when you BUY The Auto-Meter Air/Fuel Guage, it explains everything i have just said. this is where im getting my info, not just out of thin air.

 

I have a '91 Formula and the yellow light comes on at times on open highway. Does that mean I will hurt my engine in regards to an above post where the computer will think different and change the mixture? Thanks for the help! Andy

 

I assume you have an Air/Fuel Guage showing Red/Yellow/Green air/fuel mixtures?
Or do you mean the "Check Engine" light, which has no been mentioned even 1 time in this post.
If the check engine light is coming on the highway, you probably have an EGR problem, which means you might have changed the exhaust, gutted the Cat, or likewise messed with the exhaust on the car. If not, it could be anything...

If you DO have an Auto-Meter Air/Fuel Ratio guage plugged into your O2 sensor wire, then Yellow is ok, but not green.

Which light are you referring to?