Lambda sensor tests ok, could it still be the problem?

[Andy T 0]

The other week my '92 G60 started running badly the day after doing some cleaning under the engine. Found that water had got into the lambda probe connector, so I dried it out and cleaned up the contacts. The car now runs 'ok' but is overfuelling intermittently (slight black exhaust smoke and the idle sounds a bit lumpy. Some of the time it seems ok, and runs as it should on WOT.

 

I tested the lambda as described on here and i'm getting a voltage reading that cycles between 0.1 and 0.95 volts over a second or two which indicates that it's working ok. So the question is, could it still be the lambda causing the problem? can they not work intermittently or not work properly even though they output a voltage signal?

 

Could water getting into the contacts shorted the sensor out or damaged the heating element? The sensor is only about 12 months old so I don't want to Shell out over £100 again unless its definately dead.

 

Cheers for any help.

[Supercharged 2]

I'm wondering if the earth wire that terminates near the plug has got corroded...

[m3evo 0]

Hi Andy, I did exactly the same as you mate washed the engine off then noticed it running really rich black plugs exhaust etc, thought it would be the coolant sensor playing up, fitted new one just the same, then disconnected the Lambda plug( found the contacts full of water! ) and took it for a drive back to normal nearly no over fueling or missing anymore, so conclusion new Lambda ordered this week hopefully should sort it, can only assume water damaged the sensor in some way by shorting it out maybe cheers Dave

[flusted 0]

I fitted new lambda and mine still does similar thing

[Andy T 0]

I'm wondering if the earth wire that terminates near the plug has got corroded...

 

The earth is good, last time I replaced the lambda I cleaned up the earth point on the plug bracket and ran an earth wire from that to the o/s chassis strut top - I did this because the earth through the engine was not great, too much resistance.

 

m3Evo, sounds like a common problem with the lambda connector not sealing properly, maybe be worth everyone checking theirs for corrosion then sealing it up with silicone sealant?

 

Cheers

[Andy T 0]

Plugged the lambda sensor back in the other week, the car ran perfect for two days, then started overfuelling after a 30 min drive on the motorway, It was quite a warm afternoon?

 

I'm sure I've heard of this problem before where the car runs ok for 20 mins or so but then overfuels when the engine gets really warm...? Can a lambda probe really be that intermittent?