Easiest way to remove O2 Sensor - Montana van?

[1999montana]

Picked up a new O2 sensor and figured I would put it in before my next emissions test in a few days.

Is it easier to roll the engine forward to get at the O2 sensor in the exhaust manifold, or is it easier to get at it from below reaching up? Guess some PB Blaster and an over night soak might help to ease it out.

Also, should I disconnect the battery for a 1/2 hour to clear the computer and get it to re-learn with the new O2 sensor?

[Tech II]

Without a lift, there is no easy way on a Montana.....

If the vehicle is not setting a code, why open a can of worms?

[1999montana]

Originally Posted by Tech II

Without a lift, there is no easy way on a Montana.....

If the vehicle is not setting a code, why open a can of worms?

Thanks for the reply.

Maybe with 227,800 KMs on the original O2, and a drop in mileage of 25%??

[Tech II]

Last COMPLETE tuneup?

What I meant by a can of worms is, if no codes, just get the inspection done.....THEN, change the O2 sensor......suppose you have a problem taking the O2 sensor out and take the threads out with it(it's happened more than once)........now you don't have to rush getting this fixed for the inspection....

[1999montana]

Originally Posted by Tech II

Last COMPLETE tuneup?

What I meant by a can of worms is, if no codes, just get the inspection done.....THEN, change the O2 sensor......suppose you have a problem taking the O2 sensor out and take the threads out with it(it's happened more than once)........now you don't have to rush getting this fixed for the inspection....

Gotcha, and understand!

I need to do a CCC on the van and clean the throttle intake, add some injector cleaner, check the air cleaner and maybe replace the fuel filter. Plugs are good, wires are relatively new - both replaced at 170,000 KMs. PCV could use a replacement too.

I guess it might possibly be a little heavy on some of the readings, CO perhaps particularly at curb idle, but may still pass anyway. Then I can PB Blaster it plenty and take it out at my leisure (I hope). Could be a plan. Thanks.

[Tech II]

Remember, just before you bring the vehicle into the inspection station, take the vehicle out to get it at normal operating temp, and go out on the highway, and do several hard accelerations....simple trick.....but you wouldn't believe how many people bring their cars in cold turkey, and just marginally miss passing....

[rkvons]

Originally Posted by Tech II

Remember, just before you bring the vehicle into the inspection station, take the vehicle out to get it at normal operating temp, and go out on the highway, and do several hard accelerations....simple trick.....but you wouldn't believe how many people bring their cars in cold turkey, and just marginally miss passing....

Here in Illinois they just scan to see if there are any codes related to emissions. If your check engine light is off, you are good. So I never do any quick accelerations of such when a test is up and coming.

[1999montana]

3 days to emissions test and the van is acting up now with a CEL on solid.

I did a Throttle Body Cleaning (with TB Cleaner) and Combustion Chamber Cleaning using AC Delco CCC today; - I have done this at least 3 times in the last 6 or 8 years. CEL always flashes and comes on solid due to a perceived misfire, and after a couple of cycles the code clears. Not this time.

There was some debris in the honeycomb on the air cleaner side of the MAF sensor which I vacuumed out, careful not to mess up those one way diodes on the other side. Air cleaner was good, but could use a change and was sealed, so I don't know how the debris got in there. Ran great on a road trip of 250 miles despite any code(s), but it has a slight hesitation when you tap the gas pedal from idle. I think it may be time for a new MAF.

Will have a shop close to me with a $3,000 Snap-On scanner read the codes tomorrow. If it is a MAF code I'll get a new one from RockAuto and a new air temperature sensor (it's in the snorkel between the TB and MAF), only $10 for the ATS plus $134 for the MAF. Will hold off on the E-test until the new parts arrive.

I have the new O2, but figured I'd wait until after the emissions test and do it at my leisure. Probably won't come out easily without plenty of PB Blaster and some blue air words!

[1999montana]

Success!

Only one code in the ECM; - PO300 - general misfire

Totally agree with the code/diagnosis as this is consistent with delivering the chemical through the PCV vacuum port. This always causes a rough running engine while it clears the chemical and carbon out and settles down to a smoother idle. Usually the engine runs a bit rough, the CEL flashes and then comes on solid, followed by a few restarts afterwards which seemed to clear the code, but not this last time.

A little unsure why the ECM didn't clear once the engine started running on 6 cylinders after the combustion chamber cleaning was finished and the van completed a 250 mile highway run with several starts and stops.

So, finding no other codes, we cleared them and so far it hasn't returned.

Emissions test Wednesday.