New O2 Sensor = Wow!

[mws]

I replaced the O2 sensor last night, and I am impressed with the difference it made!

 

The rest of the story:

I bought my '87 pathy with 177K well maintained easy commuter miles. It drove fine, but not impressively. Within a couple days, I determined that there was a problem with the thermostat - she never warmed up fully. So I get a new thermostat to swap in. Pull the TS housing (WARNING: The Chilton book is WRONG when it comes to the location of the TS - true tripe!) and hmmmm..... there was no thermostat at all! Evidently some knuckle dragging "professional" forgot to put it back in after a repair (I know the owner, and they had only "professional" mechanics work on it). It had been several years since anyone had been inside the engine that far.

New thermostat = much better. She warmed up, and finally idled under 1200 rpm. Ran the ECM through all diagnostics and everything checked out fine. Took it in for smog check, and she failed emissions at idle. Fine at cruise. Grumble grumble.

Since it had been running in "cold engine" enrichened mode for so long, I figured the cat was likely sooted up. Pulled it out - yup. Black as night in there. Installed a new Dynomax Super Converter (only $59!) and 2.5" exhaust. Ran better, but still had a couple quirks:

- Kinda stumbly when cold

- Would miss and lurch when accelerating under 2K rpm

- blipping the throttle resulted in minor stumbles and backfires and a bit of an rpm surge right as the throttle was released. Classic sign of lean.

- Yawn inducing performance. Not having driven a good pathy, I had no benchmark to compare. Now I know the V30 is a rather low performance little V6, but still...

So - it had been years since a good tune up. New NGK plugs and wires, Bosch cap and rotor, Bosch fuel and air filters.

- Ran a little better, but still the same symptoms.

Although Mode 1 & 2 testing of ECM indicated the O2 was functioning properly, I decided to replace it anyways. It had never been changed, and it seemed that the rich exhaust condition could not have done it any good. If the cat was sooted up, then the O2 sensor had to be getting fluffy too. Unbelievably, the old sensor came right out (I had been soaking with PB for a couple days).

 

Wow! Stumbles went away, backfires gone, revs much quicker. And it pulls noticeably harder! Seat o'pants dyno says at least 20 lb-ft in the midrange. The accleration induced yawning was significantly decreased.

 

Moral: Even if it tests OK, a new O2 sensor may make quite a difference! I now understand first hand why it is suggested they be changed as part of routine maintenance.

Now to get it smog checked again.

[armelius2]

I am going to do mine. What is PB blaster?

[jason]

I did the google thing for you since I'm bored at work:

 

http://www.pbblaster.com/store/moreinfo.cfm?Product_ID=1

[Guest roadrunner2004]

Yes that is what got mine out when I took out my exhuast and put it back in therein nothing like it PB Penetrating

Roadrunner2004

[Mr. Pickles]

PB Blaster rocks. Its not a miracle worker, but I used it for the first time on my body lift install. It'll help break loose many somewhat frozen bolts, and for those that move stubbornly, it will help things along. My new plan for any future project will be to scope out what needs to be moved before-hand, and shoot them with PB for a good overnight soak or 2.

[Adelard of Bath]

I just bought this stuff called "Gunk Liquid Wrench LS4" or something, anyway it said "foaming" on it....liquid wrench is usually crap but I am a sucker for anything foamy so I got it...plus liquid wrench has been around since my Grandpa's days (in those little square cans, I still have a few!) so they must know something. Cost more than PB, like $4.50 a can or something...but like I said, it said "foamy" on the can.....

 

Anyway hooked the straw up and it was not what I expected...I was hoping it would shoot out and hit the rust and start bubbling...no, what REALLY happens is this white foam kinda oozes out the straw, so "shooting" it at bolts is out of the question...but it really seems to work great, actually I like it better than PB (except I can't shoot it so I still have PB around too) and if I foam a bolt or nut, I can come back the next day and the foam will have changed to this nice pool of oil...that will still be there days later, if I leave it that long without wiping it up, but usually the bolt just pops off so I just wipe up my socket and viola.

 

Foamy!

 

Just this evening I was replacing suspention bushings on my 79 Volvo, they were the originals, and 25 year old bolts on the underside of a car is not my idea of fun...but I foamed all the bolts the night before, and the next day, they came out with just box-end wrenches...like they were brand new.

 

I like the way Blaster will melt styrofoam though