Cat. concerter or O2 sensor causing check engine light

Hi everyone-

I am new to this but have heard good things....I am currently working in thr desert a LONG ways away from being able to conveniently leave my truck at a mechanics overnight. I used to have an 82 4x4 toy before I bought this newer one and was able to do most everything myself.

Anyhow, my truck is in need of repair, this may seem dumb to you but about 10,000 miles ago (four months) the check engine light came on and I had a diagnostic ran, they said it was both the o2 sensors, I figured nothing had come of it, truck still ran good and to buy both sensors would cost over 300$...at that point I had not been paid for over three months so some little O2 sensors didn't seem to be such a big deal, they go out right? Well besides bad emissions, thats a big deal i guess. I am a contracted wildlife biologist and have learned to never work as a contractor for a gov. agency again, they NEVER pay on time, it is like pulling teeth!! Anyhow, I decided to get it checked last week, again, this time by some idiot at a Tucson auto zone didn't even know it was a tacoma...ok she must have not been hired for her auto expertise...cash register maybe? The deming NM auto zone was very helpful, the tucson diagnostic gave a generic number and said that the catalytic converter was out....

None of these things is a big deal, they all seem easy to replace right? There are probably four bolts holding the catalytic converter on and another four between the two O2 sensors. I am wondering...correct me if I am oversimplifying! I have never owned a computerized vehicle, but the way i see it I can simply pull the battery cable to reset the computer after fixing, right?

Another question is about bolt loosening products, those bolts down there look a little haggard, heat and moisture probably corroded them away. What is suggested for loosening the Cat bolts?

Another dumb question...which part is the catalytic converter...the smaller bulb closer to the engine that is part of the exhaust manifold, or the second larger bulb that is closer to the muffler....if both are Cat. Cons how do i know which is bad?

And finaly...where do you suggest buying the right parts, keep in mind there are no toyota dealerships closer than a three hour drive from here. Autozone says that they have generic fit catcons but I do not know if I trust "generic". I bounce around in my pickup daily, chasing sheep. It needs to be the right part!

I am buying a Haynes repair manual...for some reason or another Chilton's doesn't have one for my year, I grew up using a Chiltons.

 

ok......let me see if i can be of some assistance to ya...

1-you should be able to reset the computer by disconnecting the neg. battery cable for a little while.
2-try some "liquid wrench" on the rusted bolts.....or wd-40 the hell outta it, maybe a few rounds till it comes loose, or maybe some "pb blaster".
3-the smaller bulb is likely a resonator, while the bigger bulb is the catalytic converter.
4-for the right parts, autozone will probably be ok, but if i were you, i'd go online to summitracing.com and see the high flow cats that they have, as one will more than likely work on your truck, or you can call customer service and get them to help you find the right one for your truck. autozone will more than likely be the cheaper route though.

the haynes manual isnt that bad, although i think chiltons is a little more in depth. anyway, hope this answers some of your questions.

oh yeah........................welcome to tw!!!

 

The reason for me wondering about there possibly being two CAts is that on the partstrain.com site they list the smaller bulb as a front cat? This is the photo they use:

This is a pic of the hind CAT they list:



Both of thes are under my truck, not sure why they felt the need to double up on both the cat and the O2 sensors.

Now...if I had to buy both of these CAT's it will be around 500$, and then there is the question as to whether both O2 sensors are good, to buy both would be another 300$. So how would I go about testing these individual parts to figure who is bad, I am in the middle of nowhere and the closest mechanic shops don't offer much for second opinions or selection. Money is a real issue here as I don't have much, however my truck is king in priority because it is what i depend on to make my meager living.

...and the cherry on top is that my rig is licensed in California although I am currently in NM. I will most likely be moving back there soon, so it has to be cal emissions kosher.

 

well, i guess all i can say is since you will be going back to cali......may as well do everything right the first time, because if not, it will probably cost you twice as muck after the cali emissions testing crap startsa failing your truck.

there is a chance that the cat could be out.....may have to unbolt and see if it seems clogged up(i know....kinda hard to do). i can tell you that more than likely....if your cat(s) are bad......your truck will usually run really sluggish and almost wont to choke out when you get up to speed. otherwise, if its a bad o2 sensor, it will throw a code, but im not too sure about the truck running rough.......may keep on running normal. you can try cleaning the o2 sensor with some electrical cleaner or brake/carb cleaner....but it may not doo too much.

hopefully, someone else with knowledge of the first gen tacos will loin in this thread. we will try and help any way we can.

 

A bad o2 sensor will give a CEL and hurt your fuel economy, but the truck will still run alright. I've been told that a bad o2 sensor will also make your exhaust smell different. I recently had the o2 sensor code on my truck, however, in classic Toyota fashion, it fixed itself. I'm sorry, but I can't tell you anything about the cat.

 

Get the Haynes manual. It's not bad. I too was brought up on the Chiltons manuals, like you said, they aren't available. The Haynes will tell you what many of the codes stand for and also has a trouble shooting section.

 

Thanks for the suggestions, I am not sure...the pickup does not choke out at high RPMs but it is feeling a bit less peppy(could be that I have just been driving it soo much I don't really notice when there is a gradual change). I could change some things out like the fuel filter and air filter as well, I am sure the feul filter needs it and I know the airfilter could be changed. But I will most certainly clean my O2 sensors tomorrow morning before I head out and buy some liquid wrench/bolt break free next trip to town if the engine light is still on. I imagine I will be able to tell if the CAT converter is plugged by daylighting one end? If all else fails, after trying several things, I might take it to a mechanic when I can...what is a girl to do out in the middle of the Desert? Good thing I have my taco though, I would not have trusted any other vehicle to have endured the terrain and daily use that I have had to put this rig through.

 

BTW, welcome to the TW family.

 

...this may seem assnine, but when we swapped the motor out of my 82 yota 4x4 I cleaned everything with gasoline...this may be incredibly stupid...can you clean the buildup in the cat converter with gasoline...I imagine it would not work because the build up would be non-soluble carbons...as the other buildups would have burned off. Yeah. that was a dumb idea.

By the way, the check engine light came on when I was on a wash boarded dirt road in wyoming on a pronghorn hunt, I was taking on dust from the rig infront of me a bit. The light used to come on an off in equally spaced periods...now it is mostly on with the occasional off. I used to get false excitement from thinking it fixed itself...yeah, I bought the haynes today from JC whitney...it came to something like 23$ with shipping...a little cheaper than a chiltons. I wish there was a "keeping your tacoma alive" manual, I used to have the old "keeping your toytota alive" book for my old yota, among amusing sketches of the rigs it was in lay terms...made it easy sometimes to have two references. I sold it and the chiltons as part of my old rig. The hippy who bought it at 200,000 mi and over 24 years old, fixed everything I told him it needed, loaded all of his personal belongings up, and drove it from the pacific ocean to colorado. One of the many reasons I will always drive a toyota...even if I need to keep restoring first gen tacomas to keep the mini-pickup size.

 

Luckily the o2 sensors bolts look like they are in good shape...I just do not have much for tools or convenience where I am. I will test the waters, but think that they are not going to give me trouble like the CAT bolts.

Gasoline.....yeah, thats another story. I am in BFE New Mexico and although I put in some nice techron when I can...most of the time it is mexico style gas that comes from the closest gas station...45 miles away. There is not much for options here. But the light first came on when I was in Wyoming, before that trip I had almost exclusively used Chevron's techron, maybe it is not good gas like I thought it was? It is expensive...gas is like 3.45 a gal back home right now...

 

have you thought about cleaning your mass air flow sensor.....could help out.....just BE SURE to use an electrical cleaner, like an electrical contact cleaner, or also crc makes a maf sensor cleaner....good stuff, especially if those little wires are gummed up.........could help with your problem. anyway, let us know!!

 

I pulled my MAF a while ago and both of the wires where clean, I sprayed an electrical cleaner on it twice (something in a red can that was suggested to another thread on here) for good measure and reinstalled it, I then tried to reset the computer but I had an anti theft system installed and regardless of whether it was un-armed the dang alarm sounded over and over again. I thought it reset the computer but was not sure...hence the previous question. Needless to say the town of population 46 was a little unnerved that I had an alarm sounding off. I had my previous truck stolen and the night I brought my 01 pickup home for the first time my boyfriends v6 TRD Ext Cab 2003 taco...the only car with an alarm on the block was silently broken in to and gutted of all things of any worth, when they where working my rear window the neighbor stepped out for a smoke and caught them in the act...but never actually caught them...so I needed one where I used to live. Needless to say, I had a rear slider trigger installed, it was a necessity, apprently toyota installed alarms do not have a rear slider trigger and the theives where privy to this as they broke in to a pickup with an obvious alarm system.

Long story short, yeah I did check the MAF, not sure how to check it otherwise, I do not have an ampmeter...and I am an electrical noob.

 

I bought my 04 Taco from a dealer- drove away and the CEL came on. Ran the code- faulty o2 sensor in the Cat. There's a TSB regarding this issue- ended up changing out the sensor AND the ECM per Toyota's bulletin- all under warranty. Might be worth checking out- find the TSB online and see if your truck fits the guidelines. then have Toyota diag it and replace it for free. It's been almost 2 yrs since I saw the TSB- I don't recall where I found it online, but I'm sure someone here can help!

Good Luck!
Dave

 

What does TSB and ECM stand for, I imagine it has to do with some sort of recall? I am the third owner, not sure if that makes a difference. To everyone else, I don't have the right tools to clean my O2 sensor or remove the CAT's, I will have to buy some deeper rachets, currently only have a stuby set that fits under the passenger side of the bench with me. 1500 miles away from home.

 

TSB=Toyota Service Bulletin ......not so sure about ECM

 

i think ecm = engine control management, if im not mistaken??!!??

 

bad o2 sensor changes the smell of the exhaust because of the job it's sposed to perform. the o2 sensor reads the amount of unburnt gas and air and whatnot in the exhaust flow and relays that info back to the computer so that the cpu can make intake and fuel mixture adjustments to optimize the mix. when the o2 sensor fails, the car's cpu automatically runs a "rich" mix all the time just to be on the safe side and avoid detonation since the sensor can't do it's job. that different exhaust smell is more unburnt gas coming out of the tailpipe, and that SHOULD be the only reason it smells different

 

ECM= electric camel monkeys

 

they replaced the O2 sensor and my computer per the bulletin.

TSB= tech service bulletin. Most TSB's are taken care of by the manufacturer- in this case, I believe they did it if the truck has under 100k miles. A TSB is short of a recall- kind've like a known problem that exists, but doesn't affect enough cars to create an expensive recall. It's like "if it happens, take care of it, otherwise let's not raise a red flag for the masses"...

 

Pulled my o2 sensor to put it in my new Doug Thorley 2 days ago, soaked with PB blaster, nuts were rusted round but vice grips got it there, need cat sooner or later, mines hollow, but no smog here in Fernley NV.