Service required + black spark plugs

[bb01760]

2007 Monsoon with 1350 hours on it.

Have been getting the "Service Required" Notification for some time now.

In troubleshooting have replaced:

Distributer and cap + cables

Fuel pressure regulator

Thermostat + temperature sensor.

Plugs (When started to troubleshoot this)

Today went to replace plugs as a last resort and found that all starboard side plugs are black, port side plugs look healthy.

See picture:

all spark plugs:

Error has mostly been a variant of this:

O2 sensor rich OxyB1Rich SPN65563

Any ideas what to look at next?

 

Thanks

BB

[justgary]

Which temp sender did you change?  The ECM will add fuel if it thinks the engine is cold.

Also maybe do a compression/leakdown test to make sure the mechanicals are correct.

[bb01760]

As far as I know there is a single temp sensor on this model. Just behind the thermostat housing on the port side.

[oldjeep]

Find the test procedure for the upstream O2 sensor on that side.  Sounds to me like it is dead.

[bb01760]

Thank you. Replaced the O2 sensor. Let's see if that helps. The first thing I replaced when that error started was that sensor, that was a while ago though. 

 

Thanks