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Looking down past the orange dipstick there is a sensor with one prong (a little blury )it is on body of engine , low ,difficult to access. 

spank in middle of picture .

that sensor was disconnected and wonder if that could be linked to loss of power , bad gas mileage , etc...

did not pull any code when disconnected.and terminal had that cracked rubber protector ( 2 nd photo )dangling next to sensor .

thanks

A9A2D7C7-BCDC-42B4-AD42-B9771D289C37.jpeg

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The EFI connections are water resistant and held in place with a lock tab. It looks like an oil pressure sender probably connected to the oil pressure light.

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11 hours ago, Cedric lauzon said:

Thanks that makes sense .

does it matters if terminal stays bare ? Or better to cover it with some grease ?7

Generally they had nothing but a plastic cap on the end of the wire covering the connector terminal. The boot was an attempt to keep moisture out but certainly was not watertight I would suspect it would last decades with nothing more that a terminal. Here is the deal with the EFI the reference voltage is 5 volts it needs to be water tight and secured because it is referenced with very low voltage and any deviation of that voltage is what signals the ECM to do it's thing.

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Watched the video , now you got me thinking that my loss of power could be bad oil pressure .!!!!

One of my o2 sensor is soaking in gas right now . As soon as it get cleaned and put back on  , will fire up the engine and see if this oil sending / sensor make it run better .

Still after 3 days of trying to figure out , I did learn how to read a code with a paper clip !!! why I am having less and less power as miles go by still a mystery..I guess I lltake my chances and read the codes while driving . 

Breaking down in Mexico would surely suck though !!!!

 

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I gather that there are 2 o2 sensor on the V6 

would one care pulling out the 2 nd  sensor and cleaning it up with gas even it it didn’t  pull any code ? Since the car seem to be ruining rich anyways ?

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I've never heard of anyone cleaning an O2 sensor so did a little Googling.

" Another point to consider. If cleaning sensors was practical and cost effective, like it is with MAF sensors and many other things, then you would be able to purchase remanufactured O2 sensors. The fact that no remanufactured O2 sensors are available means that no one has figured out a way to fully restore an O2 sensor that is cheaper than just replacing it."

https://www.ford-trucks.com/forums/6076-can-you-clean-oxygen-sensor.html

You might end up with a very clean but still defective sensor.

 

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2 hours ago, Cedric lauzon said:

I gather that there are 2 o2 sensor on the V6 

would one care pulling out the 2 nd  sensor and cleaning it up with gas even it it didn’t  pull any code ? Since the car seem to be ruining rich anyways ?

If cheaning it with gas worked it would get cleaned every time with a cold start. O2 sensors are made of a noble material Zirconia it eventually just flat wares down and is no longer effective. The are sensitive to contaminates early ones would fail from gaskets formed with silicone sealant because if the silica. Pretty much anything that might land on an O2 sensor carbon etc. would soon be incinerated by the exhaust heat 600* is not out of the question. I'm can't say for sure but your may have 4 two probably would actually be AF ratio sensors I think CA V6 Toyotas had 4. Bottom line there is no cleaning them, introducing cleaning mixes may well kill them. This is a complex system (read German) yeah I know it says Toyota all over it but they did not invent it all the parts have to sing in harmony. Now if you have really deep pockets you can just start throwing parts at it until you fix it or go about it methodically you may even think about taking it to an expert. Usually parts had to fail a test "X" times before it throws code so because it's out no doesn't mean it's fixed. My 2011 Tacoma had an O2 sensor code that wasn't, it was a AF ratio sensor that did not effect the operation it was related to the AF sensor heater it took me about a week on and off with fancy testers and freeze frame to get to the bottom of it in the end I had someone drive it while I watched it with the reader it is 85% more complex than a 1991. I could have replaced both O2 sensors and one AF sensor before I got to the bottom of it for about $350, + the $120 for the actual defective part.

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Nice explanations, ok so  it seems that since I gonna hit the road soon  , I should at least buy 2 new o2 sensors and one AF sensor and replace them before new codes appear on the road let s say a few hundred miles . My wife and I live in that Rv with no other vehicle to get parts  . And we feel a little nervous about these long steep hills at 20 mph !!!with every one passing us at 65 +mph . is this how you’d approach that situation ?

I did get a warning triangle for slow moving vehicle though !!!!! Would work well in an Amish community !!!

 

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In PA yes it may work. The bottom line there really is no code I can think of that would bring you to a halt it may not run well but probably will get you somewhere. Again just buying parts is not the way to go. A rich mix from excessive fuel pressure or a temp sensor issue may cause an O2 code you see my point? Nothing wrong with the sensor it just reporting a rich mix because the voltage was high from the rich mix. Me I would check the entire thing out before heading out. If there is something wrong driving around town may trigger a code. Don't disconnect any thing until you extract a code. O2 sensors can be checked with a voltmeter for activity. Diagnostics is not for the faint of heart like I said I could have just replaced parts on mine and eventually been in the $400+ range and still had a defective part.

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Don't go buying parts because I mentioned them it's all part of a big puzzle with many causes and effects. Back in the heydayday of this stuff I ran two shops and would not let my people buy expensive parts until they could prove to me they were bad or had a real good ideal that was the cause of the issue. Sometimes I had to eat parts they were not tasty.

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I only see 1 O2 sensor on my V6.   Toyota says to replace at 80,000 miles and I did not know if mine had ever been replaced.  I was on the fence but found OE for cheap. Gotta splice in no plug.

https://www.ebay.com/itm/New-Bulk-Denso-234-4050-Oxygen-Sensor-For-Toyota-Lexus/360897062129?epid=10014333567&hash=item54072424f1:g:w7sAAOSw~fpZuZZe:sc:USPSPriority!33917!US!-1:rk:1:pf:0

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Thank you guys very much  , my wife decided to only buy one o 2 sensor new ( thank you for the link ...) and the hit the road  down around Phoenix AZ ( where it’s warmer !)

and see how  many codes we can hit ...camp around some o Reilly’s and try to have a good fixing before we hit the Mexican border !

For the splicing of wire witho2 sensor ,  do wire  color match !? Or need a special trick to know ?

Gracias amigos .

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1 minute ago, Cedric lauzon said:

Thank you guys very much  , my wife decided to only buy one o 2 sensor new ( thank you for the link ...) and the hit the road  down around Phoenix AZ ( where it’s warmer !)

and see how  many codes we can hit ...camp around some o Reilly’s and try to have a good fixing before we hit the Mexican border !

For the splicing of wire witho2 sensor ,  do wire  color match !? Or need a special trick to know ?

Gracias amigos .

Mine matched.

 

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Frankly you are asking for problems splicing wires that output a max of 1 volt not to mention water intrusion. A V6 should have at least two sensors it's all about the left know what the right is doing.

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12 hours ago, Maineah said:

Frankly you are asking for problems splicing wires that output a max of 1 volt not to mention water intrusion. A V6 should have at least two sensors it's all about the left know what the right is doing.

Good point I should have mentioned how I did mine,  the sensor came with the crimp on connectors which I seldom use. Mine are mechanically fastened with western union splice, soldered. Then heat shrunk with dielectric compound.

I only see one sensor,  did a web search and looks like only the California models have 2. With the 2nd one having a different part #

 

Edited by jjrbus
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I won't argue that point they probably monitor it beyond the "Y" pipe so it reads both sides. If it only has one and in CL downstream of the cat is probably an AF sensor hench the different number. If you had to replace them all now on a modern car/truck you might have to take out a loan.

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So , looked for 2 nd o2 sensor around manifold exhaust of my v6 , if any body had a diagram cause I can only find one which I replaced front of cat converter .as well as where is that af temp sensor ?

changed all spark plugs and distributor wires , she seems to be running ok ...still a little weird on the idle when I gas full on and stop but overall she feels right . 

Doing test drive around town today .

 

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I have not had to deal with temp senor yet and hope I do not have to.  It is located with other sensors on a sensor block under the intake plenum at the rear of the motor.  I see one guy remove hood to access it.

Google temperature sensor removal, 3VZE.

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The only sensor I know of that needs an intake removal is the knock sensor that indeed is under the manifold. There should be both temp gauge and coolant temp sensor at the rear of the cylinder head. Lets see what we missed here there the ever popular 3L cylinder head gasket leak slewing the O2 readings, mass air flow sensor, ambient temp sensor, crank angle sensor, knock sensor, leaking/dirty injector,  high fuel pressure, ECM internal failure, throttle position sensor and of course valve clearance that probably has never been checked.  Sure is hard to hit a target when it keeps moving.

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yotatech.com/forums/f116/coolant-temp-sensors-3vze-224860/ I didn't say it was easy but the only thing I know of is the knock sensor under the manifold right in the middle of the V of the engine.

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  • 2 weeks later...
On 11/1/2018 at 7:32 PM, Maineah said:

Frankly you are asking for problems splicing wires that output a max of 1 volt not to mention water intrusion. A V6 should have at least two sensors it's all about the left know what the right is doing.

the VZ3E has only one - past where the 2 exhaust pipes merge into one.

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