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Toyota Plugs and Oxygen sensor.


Changeling's Avatar
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10-22-03, 04:14 PM   #1  
Toyota Plugs and Oxygen sensor.

Hello. I have a 1999 Toyota Tacoma 4x4 extended cab TRD with a V6 engine and Auto trans.
The check engine light is on but everything is running great. The dealership says it's something to do with the emissions control and want $60.00 to tell me what!
Friends say it is the, "Oxygen sensor", and I could probably use a new set of plugs.
I have 70,000 miles on everything "Original", all highway. This is acceptable in my mind and was wondering wether to use Toyota parts are after market, like Autolite platinum plugs, etc!
What brand do you guys recommend and why as replacement parts, plugs and oxygen sensor??
Changeling

 
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10-22-03, 04:38 PM   #2  
Joe_F
The owner's manual should state what NGK or Denso plug # is used. Buy them at any parts store dealing in either brand and use those.

AL is crap for most applications as they consolidate heat ranges to cover a wide range of applications...no good.

As for the MIL lamp, have the codes scanned at Autozone and tell us what they find. Don't throw parts at the problem, you won't fix anything that way.

 
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10-22-03, 05:19 PM   #3  
Don't bother with the oxygen sensor until you find out what it REALLY needs.
I wouldn't ask that particular friend for any more advice either. He has no clue. The plugs aren't a bad idea based on mileage but have nothing to do with the light. Like Joe said, have it scanned. You'll spend a lot more than $60 trying to fix this yourself by guessing.

 
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10-23-03, 04:21 AM   #4  
And OE Toyota O2 sensors have a pretty long life usually; my wife's '95 Camry with almost 160k miles has original sensor still working fine (which is nice because replacements are expen$ive). The one in my '94 Toy truck went 160k before I replaced it.

 
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10-23-03, 07:27 AM   #5  
sleepyfloyd
Originally posted by Desi501
Don't bother with the oxygen sensor until you find out what it REALLY needs.
I wouldn't ask that particular friend for any more advice either. He has no clue. The plugs aren't a bad idea based on mileage but have nothing to do with the light. Like Joe said, have it scanned. You'll spend a lot more than $60 trying to fix this yourself by guessing.
I agree with you, he shouldnt replace anything until he gets it scanned and the engine codes will point him in the right direction.

but, if he's got a bad plug,won't that cause premature fouling of the O2 sensor?

Also, I know that my Plymouth Voyager Check Engine light comes on when one of my plugs isnt firing properly... I know. because I scanned it with an OBD II scanner and it identified the misfiring plug.

so, why wouldnt the same be true for a Toyota?

 
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10-23-03, 10:18 AM   #6  
Joe_F
We need more detail on the problem/codes to be able to help.

 
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10-23-03, 11:49 AM   #7  
I am taking your advise. Where is the best place to have the engine data scanned, at the dealer or another place? Please recommend a place.

Is there a good place to purchase parts on line at great prices?
Changeling

 
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10-23-03, 12:12 PM   #8  
Joe_F
Autozone can scan for codes. Post what they find.

I don't use online sources for parts. I buy at my local parts store---far better than any online source I've seen.

 
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10-23-03, 06:15 PM   #9  
Originally posted by sleepyfloyd


but, if he's got a bad plug,won't that cause premature fouling of the O2 sensor?

Also, I know that my Plymouth Voyager Check Engine light comes on when one of my plugs isnt firing properly... I know. because I scanned it with an OBD II scanner and it identified the misfiring plug.

so, why wouldnt the same be true for a Toyota?
Ok, first of all that O/2 scenerio is one of hundreds that could be possible but not likely. That O/2 would read rich but it would take ages to foul it out. Yes all OBD II vehicles track misfire but it is very rare that the spark plug is the root cause of that problem. Something else malfunctioned to foul that plug. Your blaming the wrong component. The odds of him being right by coincidence are 100-1

 
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10-24-03, 04:38 AM   #10  
Joe didn't mention that the Autozone scan will be FREE; a lot better than $60 for a 5 minute operation.

 
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10-24-03, 05:25 AM   #11  
Sparkplugs.com is a decent place to get your plugs online.

Heed Joe's advice buy ONLY NGK or DENSO. I personally prefer NGK but I've heard DENSO is good too.

Ross

 
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10-24-03, 06:39 AM   #12  
Joe_F
Toyota may use either or both. So, I recommend checking the owner's manual to see what they use. Take that part # to the parts store dealing in that brand and you'll be all set.

Yes, AZ will scan codes free of charge. Post what they find here.

 
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10-24-03, 11:42 AM   #13  
I stopped in at a local speed shop today. I told them the story. The head mechanic said he would put my truck on the computer and check it out.
He said the computer showed a lean mixture and thought it was probable the gas filter so I had them put one in. the cost was $26.00 for the diagnostic, $26.00 for the filter (From Pep Boys), and $20.00 for installation. Total = $71.00. The engine light is off but he told me he cut it off. I am supposed to check back if it comes on.
What do you guys think?
Changeling

 
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10-24-03, 12:11 PM   #14  
Joe_F
I think you'll get the light back again.....

 
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10-24-03, 12:52 PM   #15  
Joe you might be right, it would have been a lot more helpful if you would expound a little more than "I think you will get the light back". I was told to get a diagnostic run on the truck, so I did. The mechanic said that since the gas filter had never been changed and this being a fuel injection type system (high pressure) that the possibility of blockage or interference could be making the mixture lean. He also added that it was way overdue to change the filter anyway and it was a logical place to establish a possible malfunction. That is why I went with the fuel filter.
Can you add any comments to this?
Changeling

 
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10-24-03, 12:59 PM   #16  
Joe_F
Ya, it's plausible, but I don't think that's the cause of the problem.

You simply can't guess at a problem by looking at it in five minutes as you have indicated they seemingly did. How would you know the fuel filter is at fault without doing a fuel pressure check? What lead him to believe it was "clogged"?

Yes, the fuel filter should be changed. No, you shouldn't wait for a MIL to tell you it's "bad". Fuel filters rarely cause this type of problem, but it never hurts to have clean fuel running through the system.

In short, I think that the problem is not solved.

 
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10-24-03, 02:43 PM   #17  
Want laugh...3.4 Toyoya trucks come from the factory with NGK's on one bank and Nipps on the other! Seen it many times!

By any chance was that a PO 171 lean code? If it was you need to clean the mass air sensor. Common problem they get dirty.

Larry

 
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10-25-03, 12:04 PM   #18  
First off Joe. It would indeed seem to be odd if Toyota used two different brands on different banks. However, all 6 of mine are NGK's.

Joe you were absolutely right! The light came back on today. I am going to Auto zone Monday and get the free analyzer. I will get back to you and the guys when I have some data to give you from the test. It's a 100 are more miles for me to go to the nearest Auto zone for the test so guys please tell me anything that's on your mind before Monday.
Changeling

 
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10-25-03, 12:20 PM   #19  
It going to take a little knowledge and diagnosis and not a magic wand. The lean O/2 is just the symptom and now you have to find out why. First you have to find out if the sensor is capable of going rich by artificial enrichment which watching the voltage and if so look for the cause. A vacuum leak would be my first suspect if the O/2 is accurate. Could be many things though.

 
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10-25-03, 12:25 PM   #20  
I forgot to make a comment. When I bought the gas filter at Pep Boys I priced the spark plugs for the hell of it (NGK BKR5EKPB-11, stock # 4302 . There price was $18.00 per plug!!!!!! He said it with a straight face!! I was floored!
Does this sound right to you guys for a spark plug? He said (salesman) it was because it was a "Laser Platinum"! So what.
Changeling

 
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10-25-03, 02:34 PM   #21  
Joe_F
Ya, those are one of the "benefits" of owning a foreign vehicle. Your wallet feels it when it's time to do some work....

Go to any parts store (independent) and get normal NGK replacements. You don't need laser anything. Stock replacements are fine.

As for the MIL, as others have mentioned, it will take diagnosis.

Yes, Larry is correct. NGK and Denso plugs are used interchangeably in Toyotas.

 
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10-25-03, 04:16 PM   #22  
Joe, like I said I will be heading up there to AZ Monday. Maybe then things will become a little clearer. I have more questions but will put them off until I have some computer data to show you and the guys!
Take care, Changeling.

 
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10-25-03, 04:49 PM   #23  
He said the computer showed a lean mixture
From that statement I would have to assume code PO 171 which is engine lean.

Like I said before remove the two screws holding the Mass air sensor, turn it upside down and look down in it. Find the little sensing wire that looks like a tiny resistor on a straight wire. Clean it with some brake clean. Blow it with some air.

Don't be confused by the air temp sensor which a tiny thermistor on the side. The part you have to clean is down deep inside the plastic body. You may have to shine some light down in it to see it.

You will see some fuzzy type stuff on the sensor, just clean it or if you have big $$$ replace it.

Larry

 
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10-25-03, 04:58 PM   #24  
Forgot

The little fuzz on the sensor is making the sensor lie about the air flow. It is reporting about 3 gr/sec less then actual. The computer comes up with an injection duration that is too lean.

The O2 sensors are reading a correct lean mixture

Larry

 
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10-26-03, 11:29 AM   #25  
Larry, where is the clean air mass sensor located on the engine and what does it look like? I will clean it as you suggested.
Changeling

 
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10-26-03, 12:46 PM   #26  
It is on the air intake hose that connects the air cleaner box to the throttle body. It has an electrical connector with 4-6 wires.


Larry

 
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10-26-03, 02:14 PM   #27  
Joe_F
Excellent advise from Larry. Right on the ball, as usual....

I have seen cheap air filters break up and make that "dust" that he's speaking about and drive mass air flows wacky, so this is definitely plausible.

 
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10-26-03, 02:18 PM   #28  
Thanks Larry, I will get to it ASAP.
Changeling

 
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10-27-03, 10:52 AM   #29  
Hy Guys. I went to AZ today and this guy took a little hand held computer plugged it into some port under the dash and said that there was an error PO171 on the left bank (the only error)! Looks like Larry (ToyotaMan) hit the nail on the head !
One other bit of information, last night and all day today it has rained like crazy here in Maryland. When I started the truck the light was not on and didn't come on until the engine was warmed up well, about 3 are 4 minutes or so. I don't know if this could be helpful or not.
Well does this mean that it is the Mass error sensor being dirty that is causing the problem are what? It's just plain raining to hard for me to mess with it today.
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10-27-03, 10:59 AM   #30  
Larry, a double check! When you say the sensor will be down deep inside, did you mean to just squirt some brake cleaner down to where it is to clean it off and dry it with some compressed air or to take it out and clean it.
I haven't even looked for it yet, to much rain!
Changeling

 
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10-27-03, 11:04 AM   #31  
Joe_F
You can use some electronics spray as well. That's good for electrical work and cleans out lint and crap pretty well.

I believe Larry is stating the sensing wire and the portion you have to clean is recessed into the sensor.

 
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10-27-03, 11:38 AM   #32  
Like I said before remove the two screws holding the Mass air sensor, turn it upside down and look down in it. Find the little sensing wire that looks like a tiny resistor on a straight wire. Clean it with some brake clean. Blow it with some air.
Take the sensor out of the vehicle to clean it.

Larry

 
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10-27-03, 01:33 PM   #33  
Larry, I will attempt to perform your recommendation as soon as this rain stops, it is just plain not letting up!! I thank you and will report back on the outcome.
Changeling

 
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10-27-03, 04:41 PM   #34  
Originally posted by toyotaman11769


Take the sensor out of the vehicle to clean it.

Larry

 
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11-06-03, 12:07 AM   #35  
changeling,

What was the out come of your problem?

The post you made about spark plugs is that for this truck?

Wondering.............


Larry

 
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11-06-03, 07:08 AM   #36  
Joe_F
As am I....

 
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11-06-03, 11:13 AM   #37  
Sorry I havn't got back to you guys! I havn't fixed (or tried) anything yet. I broke the two middle fingers in my left hand. Slipped on the wet grass and bent them further back than they normally want to go! OUCH!
Yes the plug question is about the sam vehicle (the new post). I have decided to keep this truck and take care of it like a baby, I absolutely love it. Take care to all.
Changeling.

 
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11-06-03, 03:22 PM   #38  
Well the plugs you ordered will not fix your problem.Your freinds said you needed plugs and an O2 sensor so thats what you are doing? I liked Toyotaman's idea better.

 
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11-08-03, 12:39 PM   #39  
Davo, I think you have totally misinterpreted what I am doing and the last comment I made!
In no way am I disregarding what ToyotaMan (Larry) said, that sir is a point of fact!
I was saying in the last statement that I have decided to keep the truck because I like it!! I am going to take care of all the problems it has, because I like it! I intend to follow Lary's instructions to the letter and perform the maintenance recommended by the manufacture, because I like it! I ordered the plugs because it is time that they are changed and when I go under the hood I might as well do it all, and because I like it!
Since I broke my hand, I don't particularly feel like doing anything to the truck! I am taking this opportunity to get the parts that the truck is due, and have them on hand.
I am doing this because I totally agree with Larry and Joe's (and some others) comments and I think "THE TRUCK" will like it! Understand?
Changeling

 
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11-09-03, 12:17 PM   #40  
Joe_F
Did Larry's suggestion fix the problem?

 
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