1994 Sidekick 16v AT 4x4 4dr virgin ECM Ruby's still there

[fixkick]

Hello Again,
Since last post I have decided to change the 02 sensor to Bosch 13073-4. My Sidekick is a Calf.  Federal Emissions label states Calif. it has 4 wires and the EGR has a temp sensor.

There must have been a problem with the 02 sensor because now the vehicle goes in to closed loop fine it's rich lean status is now rich. Go figure it changed and the pulse width drop slightly but is still above 4 ms. The O2 sensor stay roughly about .925 mv Maybe The hairline crack repair fixed the bias lean and or the 02 change. 

I did not check the new Bosch sensor before installing it, but I am getting 12 volts at BLK/WHT  and will check again for heated O2 circuit.

I disconnected the vacuum hose from purge solenoid  causing a vacuum leak and the HO2 sensor went to varing mv about 10mv to 900mv . The Injector pulse width drop to about 3 ms +or - Lean Rich status  fluctuating between both.


I going to start over and check all system and circuits again with a DVOM.
I will use the sensor and actuator testing guide that you have posted and compare them to the Tech 1
I already know that the ECT wont be accurate.

The funny thing is the vehicle is idling great it accelerates great and has a lot of power, but it is running extremely rich.
Also I looked a the ECM  the sticker says 33920-70EA0 , E2T42971 T1,  4712B A4,  US-MT and in my opinion looks like a rebuild. Capacitor has an X on it and it looks very clean.

Back to square one...
Keep you posted.

that is so true, the lean burn (EPA spec) makes low smog not max power, only rich makes max power, like in WOT mode goes rich and O2 shuts off then.
pwr is max power
mpg is max mpg.
O2 holds at Stoich, (cleanest)
A new o2 my do the trick, can be had cheap if shop around.
A 02 MY BE POISONED BY odd things, (snake oil,  or coolant leaks) best is clean fuel, and clear normal oil in the pan.)
some times a rAD leak down test finds marginal leak coolant to combustion chamber, but careful spark plug tip viewing can save the day here.