Lambda light 850 t5

[02GF74]

been reading bout how to test the sensor and also how inaccessible the plug is ....

I will try squirting a bit of WD40 to MAF plug in case water got in (although it should have dried out by now!) and same for the O2 sensors.

Also time to clean out the K&N air filter.

I ok repairing most stuff if I know what needs doing but not so great figuring out what is run in cases like this which could be one of several things....

[Luxobarge]

Originally Posted by 02GF74

Also time to clean out the K&N air filter.

Actually that's one of the first things i'd have done, if you've been through deep water you could have sucked up water into the intake which would soak the filter, and cause all sorts of running issues. Let us know what state the filter and associated pipework is in, I'd be interested to know. If there are indeed any signs of the filter getting wet, i'd be strongly tempted to replace it.

[02GF74]

Just looked inside and no sign of water. Bear in mind the intake is about 2 ft from the ground, I doubt the water was more than 6 inches.

My best guess at the moment is the water hit the O2 sensor and the rapid change of temperature broke it.

Car is 30 years old this year, 160k miles and still on original exhaust and O2 sensors, the latter I read last up to 100 k miles.

I'll have look underneath over the weekend but I expect the exhaust pipe to crumble when trying to remove the sensor.

[nickm]

The times I have got these codes it was always a vacuum leak .
PCV hose on the intake
The boost return on the intake
The Manifold vacuum tree o ring
And the Cruise control.

Originally Posted by 02GF74

Just looked inside and no sign of water. Bear in mind the intake is about 2 ft from the ground, I doubt the water was more than 6 inches.

My best guess at the moment is the water hit the O2 sensor and the rapid change of temperature broke it.

Car is 30 years old this year, 160k miles and still on original exhaust and O2 sensors, the latter I read last up to 100 k miles.

I'll have look underneath over the weekend but I expect the exhaust pipe to crumble when trying to remove the sensor.

[02GF74]

an update in case it helps anyone else.

I was convinced it was O2 sensor and decided I was not going to be crawling underneath the car so took it to the garage.

It turned out to be breather issues. There is a small diameter plastic tube (most of this stuff being 30 years old is brittle) that runs across the front of the car - this had broken and I fixed it with tape - but clearly the repair failed.

There is another breather tube near the throttle - the right angle piece fallen apart and I had repaired it but clearly too that had failed.

When I drove it from the garage the idle rpm was about 100-200 lower but after a drive on the motorway today, that seems to have cleared up. I reset the mpg and am seeing numbers in the upper 30s so that looks good as well.

I don't know how they managed to reset the EM light (and no, it is not disconnected!)

[nickm]

As I said a vacuum leak

Depending on the ECU reset can be done with a LED and a paper clip or under the bonnet port. Or when fixed 2 or 3 drive cycles.

[Baffler]

Originally Posted by nickm

As I said a vacuum leak

Depending on the ECU reset can be done with a LED and a paper clip or under the bonnet port. Or when fixed 2 or 3 drive cycles.

Nickm was on the money!

Originally Posted by 02GF74

I don't know how they managed to reset the EM light (and no, it is not disconnected!)

Indeed, once the fault has been rectified the ECU no longer has reason to bring on the EML. In some instances several start/stop cycles of the ignition can clear the error although the DTC will remain stored (historic) until such time as it's manually deleted using a suitable/capable device.

Happy days!