Back in the game/ 3.0 question
05-22-2009, 01:54 PM
#1
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Back in the game/ 3.0 question
Hey guys, Im back in the game. Picked up a 1990 4Runner 3.0 4wd today for $2500. Runs great except for an accelaration problem. Engine code is showing 21 which Ive done my research and found that its an oxygen sensor. So I called up my local Advance Auto and did a price query. Then I was asked if it was a upstream or downstream sensor. I felt like a fool because I have no idea. So my question is: Is a code 21 an upstream or downstream oxygen sensor? Please dont bash me, I tried to research this without having to do this. Thanks in advance for any help. I will post pictures as soon as I can take them, its raining today.
05-22-2009, 03:09 PM
#2
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I might be wrong here (I have had a beer or three) but I think the "upstream-downstream" thing refers to th O2 sensor being before or after the cat.
Let me do some looking and I'll get back to you.
Let me do some looking and I'll get back to you.
05-22-2009, 04:04 PM
#4
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the 1990 3vze 4runners I have seen here in california only have one sensor between the cat and engine not one after the cat.
Not really sure what year they started having 2 sensors.
Not really sure what year they started having 2 sensors.
05-22-2009, 05:10 PM
#5
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All 4runenrs and trucks sold in CA should have the two sensors plus a bunch of other sensors and emissions crap on them. But that wouldn't stop someone from buying a used runner from some other state and bringing it to cali, that's probably why the runner you saw had only one sensor.
05-22-2009, 05:17 PM
#6
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My old '91 3.0 longbed had only the 1 o2 sensor before the cat. My '91 Wa 4Runner has 1 o2 sensor as well. My FSM only shows 1 o2 sensor, before the cat.
Last edited by a4runnerfreak; 05-22-2009 at 05:18 PM.
05-22-2009, 07:17 PM
#7
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Thanks guys
Thanks for the help guys. I only saw one underneath so I guess that narrows it down to the upstream sensor. Thats why I love you guys more than my own family!
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05-23-2009, 09:05 AM
#8
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Do yourself a favor & get a replacement Denso or NGK (NTK for O2 sensors) at www.sparkplugs.com. DO NOT get a bosch...
05-23-2009, 09:45 AM
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Do yourself a favor & get a replacement Denso or NGK (NTK for O2 sensors) at www.sparkplugs.com. DO NOT get a bosch...
05-25-2009, 12:00 AM
#12
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Ya dont use the bosch. It might work for a few weeks but WILL crap out on you. It sucks to pay so much more at the dealer but in the end there is no comparison.
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