How do you know if O2 sensors and injectors are ok?

With the help of Steve M I hooked my multimeter up to the O2 sensors and checked voltages. The thread is in this area somewhere.

 

the engine light goes on, not off

the O2 sensors have nothing to do with the slow down lights, those are operated by temperature sensors and each bank a small ECU

 

Hey Bo,
On my 87 Mercedes, I borrowed a mixture sensor from my mechanic. It measured voltage from the O2 sensor and displayed the reading on an LED 'Christmas Tree". Once you got the mixture right, the green lights would be illuminated. All you are measuring is the voltage on the O2 sensor to dial it in. Like Joe Said, you can do this with a Multimeter, I just dont have the values handy.

Regarding the Slow down lights, they are hit and miss even when new. They only tell you if A) you have a cat melting (too munch fuel) or B) The Cat ECU's are failing (probable cause).

Im sure the WSM has a specific procedure for setting mixture correctly. I set mine by smell and RPM until I could get it into the shop an have it done perfectly. Turns out I was able to get it close enough to pass emissions fine, but it was a little off when in the shop.

 

I always replaced the O2 sensors when performing a major service, as a preventive measure. I believe that over time the O2s can become "sluggish" even though they are still sending signals to the ECUs. I think the duty cycle voltage range is something like 0.2 to 0.8 volts.