94 850 Turbo running rich and idling high

[Vazfx16]

The sensor is (if you are facing the car), left side, to the left of the intake manifold and to the right of the pullies . It is connected into the thermostat housing. In my situation, the plug's internal bullet connectors where not seating properly. The plastic plug with click into place as it should, but internally the bullet connectors were not making good contact. I pulled the bullet out a bit (with out damaging the thing wires), and plugged them into the female connector. Then I connected the plastic part of the connector. Everything was better instantly.

is this the sensor low on the front of the block ?

[skloon]

okay will go steal on off one of my wifes cars

[Vazfx16]

okay will go steal on off one of my wifes cars

Just remember, it may not be the actual sensor...it could just be the plug. Check the plug carefully for corrosion and a proper connection of the metal parts.

[misha]

okay will go steal on off one of my wifes cars

You can't without draining coolant a bit.

[Vazfx16]

okay will go steal on off one of my wifes cars

You can't without draining coolant a bit.

Correct. Drain about a liter or so out. Just enough so that there is no coolant in the upper radiator hose. YOu will have to then move that hose out of the way. Undoing it from the thermos housing

[abscate]

Park up hill on a curb, then point the hose to the sky as soon as it's off? That should work rather than fussing with coolant.

[Sommerfeldt]

Yes....IF it is dead and you leave it connected.It gives false reading,almost like bad Maf.
If you disconnect it's connector...all you get is check engine light.

Trust me,i've tried it numerous of times on Volvos and other cars with success.

So what you're saying, really, is that the rear o2 sensor doesn't actually do anything at all, since you can simply disconnect it, and all that happens is a CEL, and that it's only a source of potential problems? That seems very, VERY dubious to me.

- S

[misha]

What would you say on this...my friend drives a car for two years just on Rear o2 sensor which is in it's rear position,connected to a Front o2 connector and cat removed?!Rear o2 plug is disconnected.
Besides check engine light and code for a rear 02 sensor,there is no other codes.
If you have doubts try it,but you would need to remove cat.Otherwise your engine would running lean.

[abscate]

Yes....IF it is dead and you leave it connected.It gives false reading,almost like bad Maf.
If you disconnect it's connector...all you get is check engine light.

Trust me,i've tried it numerous of times on Volvos and other cars with success.

So what you're saying, really, is that the rear o2 sensor doesn't actually do anything at all, since you can simply disconnect it, and all that happens is a CEL, and that it's only a source of potential problems? That seems very, VERY dubious to me.

- S

It does, but is correct.

The rear sensor just checks the exhaust fro oxygen content after the catalytic converter and reports to the ECU AIF the cat is doing a good job. The ECU does nothing with this information, it only uses the front O2 sensor to monitor and adjust the fuel deliverd ( it uses other things too) If the rear O2 sensor reports out of range, the ECU sets the Low cat efficiency CEL

[Sommerfeldt]

It does, but is correct.

The rear sensor just checks the exhaust fro oxygen content after the catalytic converter and reports to the ECU AIF the cat is doing a good job. The ECU does nothing with this information, it only uses the front O2 sensor to monitor and adjust the fuel deliverd ( it uses other things too) If the rear O2 sensor reports out of range, the ECU sets the Low cat efficiency CEL

This makes little sense to me - if this was accurate, then a dead, dying or faulty rear 02 shouldn't have any effect at all (besides a CEL). It certainly should not have made a great big rich condition when mine went out. There's a flaw in your arguments, gentlemen.

- S