2003 Explorer Rough Idle

[Cashcrazy]

Does the o2 graph tell you anything?

 

[plasticseng]

And finally here is a graph from forscan. Plasticeng- I can send you a log with several minutes of idling if that is better. If so just msg me you email.

Was there a difference in the conditions here versus the scan from the other app above. Was one before it warmed up and one after or anything like that?

The reason I ask is that one above shows the second sensor on each bank pretty steady at around 0.8 volts, but the one off of Forscan shows them bouncing around. We need some pros to chime in here, but the one that shows them bouncing around may be the sign of a failing catalytic converter. You really want the rear O2 sensors to give you a steady reading like you see in the first graph(although 0.8 seems high). That shows that the converter is eliminating the NOx.

Your front O2 sensors look good to me. They should be switching back and forth constantly with a decent voltage spread. Yours appear to be doing that.

We need somebody that knows more than me to interpret those rear O2 sensor graphs. Help me fellas. Is that a bad cat?

 

[plasticseng]

In the Forscan data, what are the voltage ranges on the two downstream sensors? Are they 0 - .56 and 0 - .11?

 

[Cashcrazy]

The first graph was the iPhone app and it is a shorter interval of time. The forscan PC shot in the second graph should be a more accurate representation since it's a longer time interval.

Yes the intervals on the second sensors are .11 and .56. One of them seems a little off. Thanks again for all your help.

 

[plasticseng]

I really want someone else to help us out here. To my understanding, the switching on the back O2 sensors is a sign that the converter is not working properly, but my experience is really limited in that area, and I don't want you to take my recommendation on something that expensive to replace.

 

[Cashcrazy]

Please chime in if this is this your wheelhouse! I can get any other graphs needed with this new software.

 

[Cashcrazy]

Would a failing converter on one side cause only one of the LT fuel trims to be high?

 

[Cashcrazy]

I just drove a 2014 F150 and it idled like a dream.

 

[plasticseng]

I just drove a 2014 F150 and it idled like a dream.

Don't jump off the cliff yet. LOL

You may want post the O2 sensor data to another forum and see if you can get some input.

 

[Cashcrazy]

Have any suggestions?

 

[plasticseng]

TechByTrade is posting some catalytic converter advice in this thread:

http://www.explorerforum.com/forums...alytic-converter-removal.453559/#post-3578269

Maybe post your scans in there and see if he can help. He seems to be knowledgeable on this kind of stuff.

You may be able to just IM, too. I've never done that on this site.

 

[Cashcrazy]

Thanks. I just retorqued the intake bolts to specs. Nothing was loose.

 

[plasticseng]

A lot of information to absorb but very informative:

 

[Cashcrazy]

Thanks. I need to hook up forscan and go for a drive after watching that. I'm also going to see if I can find a smoke machine.

 

[Cashcrazy]

I moved to "under the hood" section and getting several suggestions if anyone cares to follow.

http://www.explorerforum.com/forums...-idle-any-obd-ii-experts.453612/#post-3579009

 

[Cashcrazy]

Just added new crank position sensor and still idling rough. I'm hitting the junkyard tomorrow if anyone can think of anything I need to pull for testing. I plan on pulling a camshaft position sensor at a minimum