91_TOYOTA_4x4

so yeah its been through 2 new o2 sensors in a year and i cant figure out why? its driving me crazy. be ware lots of text ahead.

So a little history... when i bought it it had stock manifold, downpipe, cat, then a glasspack. ran great but i didnt pass aircare, so my dad wanted a shop to look at it although i knew it was the cat... So it got a new cat and o2 to be sure. passed aircare! woooooo! i was happy. until i was driving and the downpipe just broke in half form rust so i drove it home sounding like an airplane then got a new downpipe. after this its all down hill lol. i figure this sparked the first o2. So 2 months later i notice a bit of hesitation while accelerating, didnt think much, and my parents bought me a header for Christmas so i got that put on. when i got installed there where tons of leaks around the header to the head but i didnt know this until later... the leaks sounding like ticking and it always ticked since i got it and since the 22re was always known for ticking i just assumed it was normal. While the ticking got worse until i couldn't stand it so i picked up new gasket and some rtv silicon to fix it. while i fixed that problem and couldn't believe how quiet it was and there was barley any valve tick . only problem was that the header to downpipe gasket broke so i tried to put it together with rtv until i could get a new one. well it blew and i didnt notice. then the hesitation became really bad and my cell had come on. Well i pulled the codes and it said afm, looked into it and the afm being bad sounded possible, so i got another one of a 4runner. didnt work . So then i found out that sometimes the ecu throws afm and tps codes when the o2 isnt working right. so i bit the bullit and bought an o2. Holy crap right away it ran smooth and FREAKING RIPPED!!!!! couldn't believe how much power i was missing haha. well that worked up until now (about 6 months later). took it through aircare thinking (well i have a year old cat and brand new o2 sensor and no leaks, should pass easy) nope..
So the readings from the fail pointed at the cat, i was 9 times over the limit on noX i think??? so i got a magnaflow highflow since i wanted one anyways so though alright it should pass. nope??????????????????????????????? no im pissed. So i had like 4 days until my insurance was up and guess what. yep hesitation came back a tad bit............ FacePalm

So i know its the o2 sensor but theres something else wrong here. i could replace the o2 and it would work for 6 months but thats not really fixing it. during the last o2 sensors life i had no exhaust leaks or anything to make it blow. i had a clean airfilter and the timing is dead on. So now i think maybe theres more happening than i can see, maybe the ecu is burning it up, short somewhere, idk? im lost here, i have around a 1000 dollars in exhaust crap trying to just get it run smooth and pass aircare lol. its brutal since this engine is so good to so many and i love it when it runs good but man why am i having so many problems with exhaust? lol. my buddy has a 3vze 4runner that isnt rebuilt like my truck and its passes aircare no problem and he payed half what i did for my truck. like you can see how pissed i am here.

so if you guys could help me fix this so i can sell this thing and get it out of my hair. this problem has made me loose all my love for the truck anymore and i want to move on to the 4runner. so what do you think?

here is a picture just because everyone likes pic's lmao






this is what im going to build up

91_TOYOTA_4x4

bump.... anyone?

myyota

When your replacing the 02 sensor what brand are you using ?. If its a Bosch there junk and don`t work well in toyota`s, you need to buy a Denso 02 sensor, that`s an OEM replacement.

91_TOYOTA_4x4

cant remember what the company was but it wasn't denso. weird because when i put that o2 sensor in it worked great until now lol. problem is that the factory one from toyota is like 180 bucks :O

91_TOYOTA_4x4

hmm well the reason im 99% sure its the o2 is because its doing the exact same thing it did last time. started hesitating until it would just bog unless i floored it. So you could be right about those other things but i know my o2 sensor is toast...

myyota

You can get a new Denso 02 sensor from www.densoproducts.com for about 50.00 dollars.

erock13

same here, had mine for bout 10k now and its been doin fine, no codes or anything abnormal.. and it was only twenty bucks from autozone, the denso from napa was like $45 at the time..

erock13

i think someone explained it in a thread somewhere on here, the bosch ones dont go in as far as the denso ones, so the densos seem to 'outperform and outlast' the bosches.. I really dont care as long as it works for awhile, and as soon as it starts givin me problems i can jus take it in to autozone and get another one for free..

91_TOYOTA_4x4

alright so bosch ones really arent that bad?

So where should i start?

i dont know how i could have bad compression because the engine pulls great and it was rebuilt almost 100k km's ago.

i would agree on the egr, since those do clog easy and i have never cleaned it

and when you say "weak rings / blowby." im assuming you mean piston ring? which i really doubt that since again it was rebuilt not too long ago, pulls good, no smoke out the exhaust.

would any vacuum leaks cause it? i dont think i have any but i wouldnt doubt it after 418k km's lol.

plus i will say i always get a stutter when very small amount of throttle is given, kinda like a coughing, but only at really low rpms with barley any throttle.


im not saying that it doesnt have blowby or bad compression but i doubt it.

91_TOYOTA_4x4

maybe i will fire it up tomorrow and get a video of the stuttering

91_TOYOTA_4x4

bump...

So im still not sure whats going on but i need this thing to pass aircare real bad as in im selling the truck and i cant sell it if i doesn't pass lol. again im so sure that its my o2 sensor again since im getting hesitation again but there is a better reason why it is destroying o2's. it cant be blow by because this thing burns no oil and was rebuilt not too long ago, ie not the regular pce o junk clattering 22re lol. on my sheet from aircare i passed everything except the oxides of nitrogen (NOx) at 3073.00 ppm. max allowable is 1175 ppm so im far off. everything is great, (CO) is 0.00%, (HC) is 36 ppm, all that is the driving test. the idle test reads - (HC) 20 ppm or 215 allowable, and (CO) is 0.00%. so everything else is fine??? everyone that i have seen that have had this problem seemed to be the cat but my cat was brandnew, then i bought a highflow and still no change? i know my 02 sensor is going but if i replace it, get day insurance, and this thing fails again i think im going to just go burn it in a back alley lol. i have no cel codes and im getting like 450km's a tank, and i could use an oil change but that wouldnt cause it to fail this bad. i might try and see if my egr is dirty later when it warms up but idk. please help lol

91_TOYOTA_4x4

how do i get the egr valve apart? i have it out but how do i inspect / clean the actual valve?

scope103

Some forms of silicone gasket maker are known to destroy o2 sensors (and apparently other types of sensors as well.) You can buy "sensor safe" RTV, but I don't know for sure what is different about it. DO take a look at the package that RTV came in.

How do you "know" it's the o2 sensor? High NOx almost always points to the EGR system. (The cat plays a role in reducing NOx, but if you're that high the cat is swamped.)

So: TEST the o2 sensor, don't just guess. As a start, put a voltmeter on the Vf1 terminal in the diagnostic plug, while TE1 is jumped to E1; Vf1 should swing from about 0.5 to about 5v 8 times in 10 seconds. (This is the amplified version of the raw signal, which is found on the Ox1 terminal.) If it is doing that, your problem is not the O2 sensor.

Then check the EGR system. There are lots of things to look for (as simple as a vacuum line disconnected), but one thing to keep in the back of your mind is that the plenum could be so clogged with "gook" that there is no vacuum on the EGR inlet pipe.

ChefYota4x4

iTrader: (5)

It could easily be an EGR issue causing some O2 failures. Once your truck is warm, you should be able to place your hand on the pipe into plenum from the EGR and only find it to be warm, NOT HOT AS HELL, lol. Then, with the engine idling, take a vacuum PUMP to the top hose-flange of the EGR.... raise the idle up to 2000rpm and then pump 10inches vacuum into the top of the EGR....it should NOTICIBLY drop in idle. To check the BVSV that controls whether the EGR opens or not, via coolant temp..> Put the vacuum pump on the bottom line of the BVSV and vacuum GAUGE on the top line...When warm, pump air into the lower one, the top one(gauge) should read and hold vacuum(just do 10" again). When cold, it SHOULD NOT allow any air to pass through....if it does, it's toast. The modulator can also be a VERY common cause of smog pass failures that appear to be the EGR itself...you can verify this by doing those other tests.

Far as cleaning the EGR, you want that angled lil pipe that is around half way down the larger pipe to be clear. It's held in with a tiny screw on my truck(that lil side pipe is). You can also separate the two sections of pipe(where that big nut is) with a lil work, and really get in there and clean it out. Just clean all the pipes around it and not the plunger inside, itself. However, you can do that vacuum pump test into the top of the EGR while the motor is and it will tell you alot, as to whether the plunger even works.

I'll check my troubleshooting thread to be sure on those tests, etc.... I was trying to verify/eliminate that a bit back.

ChefYota4x4

iTrader: (5)

PS> X2 ON THE 'CERTAIN THINGS DESTROY O2'S'! There is a couple sealants that are recommended....most others are NOT, lol. Also, being extremely rich for any period of time could cause your O2 to takea hike on ya.

X2, as well, on the Ox-? terminals test of the functioning of the O2 sensor. Is it Ox-TE1 the ones to loop, Scope? PS> doesn't it have to be fully warm and OP. Temp in order for the O2 to be in Closed loop and functioning?

BajaRunner

I had ridiculously high NOx levels and the only thing that helped was getting a new cat. It went from 900 ppm to 1 ppm.

You need to pull the EGR valve off and inspect to see the valve opens and closes. You can just take the vac line to the top and suck on it and see the valve moves. Also try and test the EGR vacuum modulator, and the VSV (or TVVV -Thermal vacuum valve) that is in line with the EGR operating.

The port that runs the length of the plenum and feeds the intake with the EGR gasses clogs up and won't allow the proper flow of gasses to ricurculate. Clean that out with a coat hanger and a few bottles of carb cleaner.

91_TOYOTA_4x4

ok thanks for the reply guys!

i know some silicon can wreck things so im most likely going to go get some new gaskets.

i know my o2 sensor is bad because the same thing has happened to me before. as it goes bad i get hesitation around 2000 to 3000 rpm, to the point where my truck just plain sputters out. i replaced the o2 sensor and it fixed it right away, had tons of power and was great for 6 months lol. the egr most likely is causing this...

So i got the egr valve off and am now in the process of cleaning it. and man does it have some nasty carbon buildup lol. im almost certain this was the cause. and it was most likely killing my o2 sensor. i have been cleaning it for a while now but i have to wait for my friend to get here to get that big sleeve bolt off.

and yes Chef that little pipe on the cast piece is completely clogged lol. im trying to get it clean still...

oyah my intake is clean inside. i have checked like 4 times since i have owned it and its always shiny and clean inside. at least something is haha

BajaRunner

The EGR port that runs the length of the plenum (from the back all the way to the left side of the front) is not visible by looking through the throttle body. Its just an extension of that copper/cast pipe, and most likely just as clogged!

ChefYota4x4

iTrader: (5)

Yeah, that 1/4" or so angled piece that comes out of the side of the pipe, facing upward?....It can get so clogged and with REALLYYYYYYYYY hardened stuff, that it needs to be soaked in parts cleaner for several hours and then reamed with something strong but flexible, like a lil-teeny welding rod, lol. I helped a guy as best as I could, Rob2Tech, with a "putting things back together properly" type of deal, and when we took his off(which was REALLY difficult to even get that lil thing off), it was VERYYYYYY difficult to clean. He ended up putting it in an empty bottle and filled it with parts cleaner and let it soak for several hours(I think it was 24 hours)...and even then, it took a bit of coaxing to finally get the reamer through there, ya know? The larger pipe is much easier to clean.....and should be fully cleaned out, as well.

Also, ....you can test it and have it respond to vacuum pump tests, pulling on it with your breath to watch the valve move, etc.....but if that lil thing is fully clogged, the system itself cannot actually pull air where it needs to at times, obviously, and that will cause issues.

Hope you get this all SUSSED UP AND DONE, quick!

Mark

Windsor

The inventor isn't necessarily the best producer, those two details are very disjointed. IBM invented hard drives and produced some of the crappiest units I've seen (and they later sold that division off to Hitachi).

I've had mixed luck with Bosch O2 sensors, so "meh".