O2 sensors, dead?

[Lacoste82]

Hey, i followed a description i found in the forum inhere, on how to measure the voltage from the O2 sensors, to see if they where workign proberly. I did so, took my analog voltmeter, plus pin on the OX1 port in the diagnostics switch, the minus pin on the batteri minus, i could read a resistance, ohms, when i did so the engine sorta slowed its idle, but i couldnt read any voltage what so ever, tried every setting on the voltmeter, but to no prevail - So basicly, my O2 sensors a reading 0V - My supe is running something like 11mpg, which is why i tested the O2 sensors to begin with!

 

So what i basicly would liek to know, am i doing the measurement correctly, can i be sure the O2 sensors are gone and that they are to blame! Reason im in doubt, also has to do, with reading, that if the O2 sensors where faulty, the car would run aroiund 15 mpg, and im all the way down at 11mpg, ive checked the brake/calipers, to see if they had blocked during the winter, but that is not the case! I also had an error 42(speed circuit signal) - And i have no idea why, i do not have a delimiter on, saying this caus i know some get this error when installing these!)

 

So what am i lookign at here!?

 

Thx in advance!

 

P.s. If it turn out that i need 2 couple of new O2 sensors, ill be very happy with any links to online dealers of 02 sensors for a 93 japs spec. n/a, the local Toyota dealership is far from reasonable!

[stevie_b]

Code 42 sounds like a broken buffer circuit in the odometer. You can bypass the buffer circuit to fix it, or fit a new odo but that's more hassle.

 

11mpg does sound like tired O2 sensors.

[Lacoste82]

Ohh, im just glad it can be fixed, ecxatly how do i bypass it? Can the broken Odometer, be of any caus to the low milage, or is it just a coincidence!?

[Lacoste82]

Btw, where is the Odometer located?

[stevie_b]

The odometer is the thing in the centre of the dashboard that counts up the total miles the car has done. The odometer won't have any effect on the excessive fuel consumption. To bypass its buffer, refer to this diagram, cut the wire from pin 6 and splice the loom-side of the cut to pin 5's wire. Do this at your own risk, but I've advised other people to do it and no-one's had a a problem with it.

[Lacoste82]

Okey, cool! ANd this wont have any sideeffect, that u know of? It will still "count" the miles, show speed and so on, might be a noob question, but just to be sure! :0)

[stevie_b]

It shouldn't have any side effect. I'm not sure what the buffer circuit actually does. If my instructions above are at all unclear then do ask again: best to be sure than to guess and get it wrong!

[Lacoste82]

Thx Stevie, after looking at the diagram, it seems that it focusing on mpg speedos, mine is a kmph, as im danish, does this have any influence?

[stevie_b]

The diagram actually assumes your speedo measures in kph (as per Japanese models), so it should be fine for what you want. You only need to refer to part of the diagram: most of it is irrelevent. I posted it because it shows the pins of the odomoter plug clearly (and numbered), so you can identify the odometer's signal in and signal out pins. Ignore everything else.