Source of oxygen sensors?

[John]

Anybody found a non-Mitsy source for oxygen/lambda sensors?

Got a dead one on my high-emissions MOT failure GDI and the dealer wants £303 for a new one!! :shocked:

[The Vee]

try these


http://www.gendan.co.uk/oxygen_sensors.php

[Kenneth]

You might want to check the original part number and make sure you get the correct replacement. the GDI is a lean burn engine, so the oxy sensor might need to be a bit more complicated than a standard one

[pezza]

Cheers Andy for that link... have you used these folk before?

Looks like my sensor may need checking too. How can units be these tested?
Or are they just normally changed as one of the suspects for really bad fuel consumption, unnaceptable AFR readings or emissions failures?

My car is on about 125K miles now... consumption seems to be getting a whole lot worse and can smell the richness in mixture much more frequently. I understand these devices are supposed to be changed at some point (suposedly have a life span 60-80k miles?? Dont quote me) but has anyone actually changed theirs?

If so, for a non mitsu one?

Are they 4 wire sensors?

Thanks folks...

Pezz

[John]

Thanks for the responses so far (any more please??).

I'd already contacted Gendan (being the only UK sensor specialist I could find on the net). They said that my car isn't listed but that [quote]

"Mitsubishi vehicles tend to use standard 4-wire Zirconia sensors and our
universal 4-wire should be suitable:

http://www.gendan.co.uk/viewproduct.php?product=O24WIRE"

However I've seen various sites that say that universal sensors are 5ohm whereas some Jap cars use 12ohm sensors. My manual says sensor should be between 11&18ohm. This suggests a universal won't suit.

Pezz, my net investigations seem to confirm your belief that the sensors should be considered as a service item, changed somewhere between 60-100,00. (Dead sensor will lead to fail-safe anti-stall over-rich fuelling at low revs leading to carbon fouling and possible cat damage.)

Simple check is for continuity/resistance between pins 3 and 4. I understand they usually fail open circuit. Looking at the end of the sensor plug with the flat side at the bottom, the pins number 1 to 4 from left to right.

[Wodjno]

Can the originals be replaced with a wideband sensor .. :inquisiti

[Kieran]

Thought it was the output voltage that mattered, not the resistance? :inquisiti

[John]

Quite right Kieran; voltage is what you want to see. However first check is that the heater circuit is OK i.e. resistance on pins 3&4. Functional check is to connect voltmeter to pins 1&2 and rev engine. Volts will swing between about 0.4 and 1 volt. Manual says that 12v should be connected to pins 3&4 while volts checking but both mine gave same (expected) results whether powering the heater or not.

So I'm now confused. My sensors seem to be working but Mitsy say one isn't and their diagnostic equipment will not find any other faults until I replace it. By the way £303 was without the VAT!! I've bought complete cars for less.

I may be trying a universal one soon.

[ghanda]

Strange - I asked Mitsi for a quote today
MR507750? £158 inc VAT for the VR?

[pezza]

Strange - I asked Mitsi for a quote today
MR507750? £158 inc VAT for the VR?


Maybe the GDi ones are different? :inquisiti and needs more than 1? no idea :rolleyes4

But I may go with mitsu in that case being a lot less than 300!

[scc]

Gendan said they do one for 94.95 which I think is still :rolleyes4

A local autoparts said a universal one is no good on our cars either...his mate had a mitsu too and had to OEM it.

Anyone got one lying around?

Cheers,
scc

[Kenneth]

using a multimeter isnt nessecarily a good indication of correct function.

In closed loop running you should switch across the (approx) 0.5V mark around 10 times per second. If your oxy sensor is buggered this rate can slow and interfere with the running of the engine.

I am repeating myself here, but dont forget that the GDI is a lean burn engine. at idle it can run something close to 40:1 A/F IIRC

It does this by injecting directly into the cylinder as late as possible in the compression stroke and with the use of large amounts of exaust gas from the EGR unit.

In mixed mode it runs in the 20s:1, standard is the good old 14.7 or whatever.

Anyway, it has to have SOME way of getting these AFRs correct... one of the obvious possiblities is a special O2 sensor

[John]

Thanks Kenneth. I'll put a 'scope on the output and see what I'm getting. Certainly appears that the GDI uses special sensors.

Knew I should have bought a VR4 - far less trouble!

[Kieran]

Knew I should have bought a VR4 - far less trouble!

lol - dont read a statement like that very often! /lol

[Kenneth]

lol - dont read a statement like that very often! /lol

Its bloody true though! The GDI are a right pain in the backside if something stuffs up. I got a VR-4 for that exact reason :P