O2 sensor thingy HELP!

Post Wed Apr 20, 2005 10:52 am

Hi all,

Still got a bloody idle problem with my car (89 325i) and have decided it must be the O2 sensor (if its got one!) that has never been changed.

Where can i get a new one from? looked on the net and can only find the US of A?

Post Wed Apr 20, 2005 11:25 am

Being an 89 325i it most likely does not have a O2 sensor. Only the late E30s had them.

Ive never seen an E30 with a Lambda sensor (my 91 325i did not have one) so Im not sure where they exactly in the exhaust it would be fitted.

Check to make sure you have one - take a look from the exhaust manifold down the downpipes, it should be somewhere around there as it needs to be fairly close to the engine. You may need to look from under the car.

If you do have one and you want to buy a new one then you can buy universal lambda sensors- much cheaper than BMW!
The Lambdas for my S50 were Ãƒ”šÃ‚£100+ each from BMW but I got some universal ones for Ãƒ”šÃ‚£40 each from Hickley Valtone.

Theres a Hickleys in Bristol here so they should be able to sort you out.

You will need the 10 digit code for the sensor, I think its 0258003074, but it can be found here to check.

HTH

Post Wed Apr 20, 2005 11:32 am

cheers,

ill have a butchers when i get home to see if its got one, I just recall seeing an engine managment diagram and it had one on?

Post Wed Apr 20, 2005 1:39 pm

Is it possible to retro fit a lambda sensor, and would there be any advantage to doing so anyway?

Post Wed Apr 20, 2005 1:50 pm

they're only useful for telling the ECU info if your car has a CAT (is this correct)
For parts, have you tried this? http://www.realoem.com/bmw/
Put in the last 7 digits of your chassis no, and it'll bring the details of your car, you should see if it has a CAT or 02 sensor by searching through the pages/diagrams. Listed in $ but the part nos correspond to items available here in the UK. I have ordered many new parts for my e23 Alpina B10 and that's an 85 car, and have no problems getting parts or info.

Post Wed Apr 20, 2005 2:37 pm

There are no advantages and a couple of disadvantages to retro fitting an O2 sensor to a 'Cat ready' car.

Because the car will run on a stoichiometric mixture near permanently you'll lose power because it won't allow any enrichment at WOT/high rev's and your economy will suffer because the mixture won't lean out when you're cruising along gently (If you do that sort of sick thing

).

This is one of the reasons the Catalysed European and Americas market E30's produced less power than our free(er) breathing motors!

Post Thu Apr 21, 2005 11:22 am

AndyG wrote:they're only useful for telling the ECU info if your car has a CAT (is this correct)

The sensor measures the oxygen in the exhaust gas. Cars with Cats need the lambda sensor to feed back info to the ECU on the air/fuel mixture.
It helps the engine run at the ideal air/fuel mixture of 14.7:1 (the stoichiometric point) and also to keep enough oxygen in the exhaust gases to allow the Cat to do its job properly.

If the mixture becomes too lean or too rich then the Cat will not function properly and can actually be damaged, mainly by overfuelling.

If your car has a lambda sensor fitted, you do not need to have a Cat fitted as well.

I dont think there is any advantage in retro fitting a lambda sensor, unless your doing a turbo conversion, where the exhaust gases need monitoring.

Post Thu Apr 21, 2005 10:45 pm

Easiest way to tell if your car has a lambda sensor, without crawling under it, is to find the socket clipped under the battery tray.
It is a round four pin socket, about 25mm diameter, which, in most cases will be blanked off with a dummy plug and rubber cap. If the plug part has a wire coming out of it, then, on the other end of that wire will be a lambda sensor.

Post Fri Apr 22, 2005 8:19 am

my battery is in the boot?

i presume that there would be a socket/plug type thing in the same place as where the battery would be if it were in the front?

i am having a play this weekend so ill have a butchers, but drove the baby last night and my idle is getting more and more un stable, its annoying me now..... anyone got any idea's?

Post Fri Apr 22, 2005 10:13 am

This should of been asked before, but what exactly is the problem with the idle?

Post Fri Apr 22, 2005 10:20 am

two probs really,
first, the idle fluctuates between maybe 500 and 900 constantly. there is no change when warm or cold.
second, when the throttle is blipped from idle it stutters as though there is an air leak, (there is not one as far as i can see) this could be the throttle position switch i suppose, but im stuck!!

any idea's