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Oxygen sensors?

Posted: Sun Sep 11, 2005 6:07 pm
by ludacris
Does it matter if they are fitted on either side of an eight. Do they have to be fitted where two pipes are joined or four and do they need to be close to the motor for the tempreture to be above 350 degrees.

Where is the best place to get them at a good price here in Brisbane. It is a 3 wire one. Would a second hand one do the job or is it best to go new.

LudaCris

Posted: Sun Sep 11, 2005 6:23 pm
by skippy's GQ
best to go new, and most V8's run one per side so the coputer can trim the fuel map for both sides

Skippy

Posted: Sun Sep 11, 2005 6:54 pm
by 80UTE
Ive got a Motec running my big block and i put the Oxygen sensor at the first collector at the end of the header pipes so it nice and hot and it works fine with a single sensor. I did have to run a wide band heated 5 wire sensor and it wasn't cheap but thats what it needed.

wally

Posted: Mon Sep 12, 2005 2:04 pm
by corkhead
was looking for info on these

i have v6 pajero and thinking my sensor is up the stuff - very bad fuel economey and brand new engine - replaced everything except this ...had bad fuel eco b4 the changeover ...

ive heard this can contribute ?

so question is - can you run anytype as long as same wire format is used ?

Posted: Mon Sep 12, 2005 3:04 pm
by Tiny
what model v8, most older engines will have one single sensor, 3 wire are heated, only use them when they are to far away from the manafold where there is not enough heat to work properly

Posted: Mon Sep 12, 2005 7:01 pm
by not not
Ludacriss motor is a 351 windser which i think is from a f150 import
Motor has just been fitted to his Gq wired and just had full exzaust fitted But dont know why he needs a new senser or fitting unless zorst shop choped it out?

Posted: Mon Sep 12, 2005 7:30 pm
by Rhett
Im running a vitara one in my serria with a 121 throttle body and computer. It runs rich until it warms up as I only have two wires comming off the computer but three coming off the senser.

Posted: Mon Sep 12, 2005 8:52 pm
by -Scott-
corkhead wrote:was looking for info on these

i have v6 pajero and thinking my sensor is up the stuff - very bad fuel economey and brand new engine - replaced everything except this ...had bad fuel eco b4 the changeover ...

ive heard this can contribute ?

so question is - can you run anytype as long as same wire format is used ?
Corkhead

I put an aftermarket mixture display in my Sigma, and the instructions with that said most sensors work exactly the same way. If you've got the same number of wires you should be fine.

More wires means a more "sophisticated" sensor. A heater element brings the sensor up to temperature faster, giving you a better cold idle (which is also required to get cars past emissions tests.) Two wires for the sensor signal means the sensor voltage at the computer is more immune to transients from power surges.

I have no idea why a sensor would use five wires. That's new to me!

Cheers,

Scott

Posted: Mon Sep 12, 2005 8:56 pm
by murcod
corkhead wrote:was looking for info on these

i have v6 pajero and thinking my sensor is up the stuff - very bad fuel economey and brand new engine - replaced everything except this ...had bad fuel eco b4 the changeover ...

ive heard this can contribute ?

so question is - can you run anytype as long as same wire format is used ?
Have a read of this post. I wrote it for the Daihatsu section regarding the single wire sensor used in the Feroza, but the info will still be relevant and give you ideas on how to check things. ;)

http://www.outerlimits4x4.com/PHP_Modul ... hp?t=24862

Posted: Mon Sep 12, 2005 8:58 pm
by murcod
BTW NGK make NTK oxy sensors which are available from most auto spares shops

http://www.ngk.com.au/content.php?page= ... 13&hl2=l14

http://www.ngk.com.au/content_feat.php? ... 29&hl2=l20

Posted: Tue Sep 13, 2005 6:52 pm
by bigpat
Corkhead, a dud oxy sensor can make the engine run like a pig. Basically the ECU doesn't get feedback on mixtures to trim it, and switches to open loop mapping, which is a fixed fuel/ ignition map against load.

When was working on V8 Supercars we put the oxy sensor after the collector (4 into 1 system), so each bank had a reading and was trimmed. However we got them dynoed with a sensor on every cylinder to set individual trimming. (MoteC & Autronic ECU's)

The best sensors we found were Bosch wide-band lambda sensors at $400-$500 a pop :shock: . Only lasted 50 hours of running on Avgas in our Formula Holdens :cry:

However the sensors on Gen 3 Chevs are wide band, and appparently $100-$200 each from memory.....

Posted: Tue Sep 13, 2005 6:53 pm
by bigpat
Corkhead, a dud oxy sensor can make the engine run like a pig. Basically the ECU doesn't get feedback on mixtures to trim it, and switches to open loop mapping, which is a fixed fuel/ ignition map against load.

When was working on V8 Supercars we put the oxy sensor after the collector (4 into 1 system), so each bank had a reading and was trimmed. However we got them dynoed with a sensor on every cylinder to set individual trimming. (MoteC & Autronic ECU's)

The best sensors we found were Bosch wide-band lambda sensors at $400-$500 a pop :shock: . Only lasted 50 hours of running on Avgas in our Formula Holdens :cry:

However the sensors on Gen 3 Chevs are wide band, and appparently $100-$200 each from memory.....

Posted: Tue Sep 13, 2005 7:21 pm
by murcod
bigpat wrote:Corkhead, a dud oxy sensor can make the engine run like a pig. Basically the ECU doesn't get feedback on mixtures to trim it, and switches to open loop mapping, which is a fixed fuel/ ignition map against load.

...
They can also respond slowly to mixture changes but still stay in closed loop. This gives surging and poor economy (and was what mine was doing ;) )

Posted: Tue Sep 13, 2005 8:01 pm
by DamTriton
Corkhead

One other thing that may be worth checking is the temperature sender/thermoswitch that goes to the ECU. If these stuff up, the computer doesn't recognise the engine has warmed up and stays in open loop mode. making it run like a pig and guzzle juice. May or may not throw a code, depending on the ECU.

Another problem causing poor running are IAC (Idle Air Control) motor not functionong or sticking. This is usually across the throttle body, linking one side to the other (essentially the idle air bleed screw on a carbie). Depending on the vehicle it can be a seperate item. Did you reuse this in the new setup?

Bad connection somewhere in the loom?

Posted: Tue Sep 13, 2005 8:34 pm
by corkhead
well theres a lot to think about ...

thanks for the input guys ...this site rocks !!

ive got to drop it back next week get the head retensioned ....so will get it on the dyno and a good tune - ive found out that they did
detune/retard my timing until i came back for the retension, someone told them i had a heavy right foot :) so see what they say

i still prefer a non computer engine ....too many things to look at when something isnt right :(

Posted: Tue Sep 13, 2005 8:40 pm
by DamTriton
Corkhead

One other thing that may be worth checking is the temperature sender/thermoswitch that goes to the ECU. If these stuff up, the computer doesn't recognise the engine has warmed up and stays in open loop mode. making it run like a pig and guzzle juice. May or may not throw a code, depending on the ECU.

Another problem causing poor running are IAC (Idle Air Control) motor not functionong or sticking. This is usually across the throttle body, linking one side to the other (essentially the idle air bleed screw on a carbie). Depending on the vehicle it can be a seperate item. Did you reuse this in the new setup?

Bad connection somewhere in the loom?

Posted: Tue Sep 13, 2005 8:41 pm
by corkhead
well theres a lot to think about ...

thanks for the input guys ...this site rocks !!

ive got to drop it back next week get the head retensioned ....so will get it on the dyno and a good tune - ive found out that they did
detune/retard my timing until i came back for the retension, someone told them i had a heavy right foot :) so see what they say

i still prefer a non computer engine ....too many things to look at when something isnt right :(

Posted: Tue Sep 13, 2005 8:47 pm
by DamTriton
This site has the stuttuttutters tonite