How are you guys installing these on a single wire setup? I need to convert since my long tubes are causing the computer to go in and out of closed loop. I understand there is a power and ground but what about the 2 other wires? Looking at a schematic(late model LS1 f-body) each of those wires look to be signal(high & low) if I'm correct. Any help is appreciated!



------------------
David Tuschhoff
1991 RS/Z28 Camaro
FI 355ci NA SBC V8 M5.
12.47 @ 110.7mph 1.80 60'
Best mph of 111.6.
My f-body page!

 

Two wires power the heater. One goes to the ECM and the last is the sensor ground (3 and 1 wire sensors ground through the sensor body).

 

Looking at the schematic, it says there is a ground, power, high signal and low signal where both of the latter two feed the computer. How do you get 2 wires that power the sensor out of this?



------------------
David Tuschhoff
1991 RS/Z28 Camaro
FI 355ci NA SBC V8 M5.
12.47 @ 110.7mph 1.80 60'
Best mph of 111.6.
My f-body page!

 

You probably got the wrong sensor. Did you get a vette ZR1 sensor ?? That one should have 3 wires. Two white wires for power and ground for the heating element inside it and one black wire for the signal to the ECM. I'd return what you have and get one of those... That doesnt sound like a sensor you could use with the ECMs in our cars.

------------------
1991 Z28 5.7 TPI

ZZ4 heads, ZZ4 cam, Harland Sharp roller rockers, Accel base, SLP siamesed runners, 52MM SLP Throttle Body, Hooker Headers, Flowmaster catback, MSD6A ignition, Home made ramair system, 2500 stall, bullet proof 700R4, aluminum driveshaft...

Soon to be installed. WC T5 !

 

1. +12v for the heater
2. Grd for the heater
3. Sensor ouput to ecm
4. Grd for sensor to ecm

I never said 2 wires power the sensor. I said there are two wires for the heater.

Perhaps my description was poor. My appologies.

 

You can get a 3-wire O2 for a '92 Astro VIN "Z" code. It's the same heated sensor without the redundant ground.

 

Thanks guys! I haven't bought the sensor yet, we had some here at our shop and I'm thinking I may try to use one.

Brent, so I can run the 2 grounds together then?

V8 astro, from what I've been reading the 4 wires work better.



------------------
David Tuschhoff
1991 RS/Z28 Camaro
FI 355ci NA SBC V8 M5.
12.47 @ 110.7mph 1.80 60'
Best mph of 111.6.
My f-body page!

 

I would ground them directly to the engine. This is where the single wire O2 grounds to through the exhaust manifold and cyl head.

[This message has been edited by Brent (edited October 27, 2001).]

 

Yeah, probably does. I figured I say just in case the 4-wire ends up costing a bunch. I know the 3-wire kind isn't that much. I think I may try that on mine. My Y-pipe is where the factory O2 sensor was but I moved it when I did the swap. Hmmm...

 

http://www.goautocenter.com/super_deals.htm
$20 for a 4 wire

 

FYI, The 'redundent' ground is there because the PCM that these sensor's usually work with will run diagnostics on the heater circuit itself to see if the sensor's heater is working to specs.....

The three wire one is a 'dumb' heated O2 and doesn't have daignostics run on it by the PCM. If the heater element fails, the PCM never knows. Either one can be made to work on our cars......

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

The Minnesota F-body Club

 

If you have a 1-wire now then get a 3-wire. The extra sensor ground on the 4-wire is supposed to go to the ECM together with the sensor signal to minimize signal error. If you don't have that ground now, then you don't need a sensor that has it.

3-wire is a heated 1-wire.
4-wire is a heated 2-wire.

The two heater wires are usually the same color. connect on to ground and one to 12V. Polarity does not matter for the heater wires.



------------------
Jonas Bylund

 

I have used this sensor succesfully for a while now...I used the extra wire as a redundant ground.

The only problem I have run into is that it still takes forever to go into closed loop due to the closed loop delay in the '165 code. I am going to adjust this eventually.


GregF
87 IROC

 

AHHHH... That's right!! Sorry bout that folks. I was mistaken about the heater diag stuff... JoBy is right about this. The extra ground is to ground the sensor's signal output to the same ground as the PCM to keep that issue from being an unintended variable... The heater diag stuff operates using the heater element being grounded through the other ground wire that a 3-wire sensor would also have....

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

The Minnesota F-body Club