O2 sensor question for my 1st gen pickup

drpdmazda · 11-09-2009, 08:05 AM

hello everyone, i recently picked up an 87 4x4 x-cab pickup and have a question regarding the O2 sensor. the sensor i have a question about is the one closest to the header in the downpipe. the truck i bought has an O2 sensor there but it isnt plugged in to anything? it has a rubber boot on the end of it that really looks like a boot that would go through the firewall. I cant find anywhere on the firewall that it would have come out of and i cant find a plug that it is supposed to mate with. it has a yellow 4 prong plug on the end of it but i cant seem to figure out where it plugs in at. any help would be greatly appreciated, i can get pics of what i am talking about if it will help. also i was wondering if someone can tell me how to read the codes to see why my check engine light comes on and off periodically. the guy had the head off and when he put it back on he didnt hook up the vacuum lines properly so they were a little out of whack for a short time, they are all fixed now and i did a fresh tune up and fluid change to the truck so i just need to figure out the O2 issue and the engine light and it will be good as new again. forgot to mention it is the 22re motor

thanks

-jason-

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83 · 11-09-2009, 09:23 AM

You don't have a first gen pickup

drpdmazda · 11-09-2009, 09:32 AM

Quote:

Originally Posted by 83

You don't have a first gen pickup

your right +1 for you, sorry about that my second gen pickup

4Crawler · 11-09-2009, 10:53 AM

How to read check engine light codes:
- http://www.4crawler.com/4x4/CheapTri...CheckConnector

There should be a plug for the O2 sensor someplace low on that side of the engine. And I think there is only one sensor on that vintage 22RE, don't think the post-cat sensors started until the '90s model 50-state smog engines.

yota4runna · 11-12-2009, 05:52 PM

Your 1987 truck came with one O2 sensor in the exhaust manifold, and it's a one-wire sensor. It plugs into a yellow connector that breaks out of the wiring harness going to the brake master cylinder cover:

If you have two four-wire sensors in your truck, you may have a later model engine and/or exhaust system.

drpdmazda · 11-15-2009, 04:15 AM

Quote:

Originally Posted by 4Crawler

How to read check engine light codes:
- http://www.4crawler.com/4x4/CheapTri...CheckConnector

There should be a plug for the O2 sensor someplace low on that side of the engine. And I think there is only one sensor on that vintage 22RE, don't think the post-cat sensors started until the '90s model 50-state smog engines.

thanks for that link, i used to have that saved in my favorites until my computer crashed. i havent had time to get under the truck and look for the plug yet but will update as soon as i do

drpdmazda · 11-15-2009, 04:17 AM

Quote:

Originally Posted by yota4runna

Your 1987 truck came with one O2 sensor in the exhaust manifold, and it's a one-wire sensor. It plugs into a yellow connector that breaks out of the wiring harness going to the brake master cylinder cover:

If you have two four-wire sensors in your truck, you may have a later model engine and/or exhaust system.

there is indeed only one O2 sensor that is in the manifold but it does not fit the plug that you have pictured. i have that yellow plug on my inner fender near the master cylinder but the plug on the sensor does not fit that one. the plug you have shown is black and the plug on my sensor is yellow? i am going to get a new sensor on wednesday to replace this one and see if maybe the previous owner had the wrong sensor and that is why its not plugged in.

11-09-2009, 09:23 AM	#2 (permalink)
83 Registered User Join Date: May 2008 Location: Montana Posts: 1,691	You don't have a first gen pickup __________________ Zach '83 Shortbed 4x4 L52HD Rebuilt & Mostly Stock

11-09-2009, 10:53 AM	#4 (permalink)
4Crawler Contributing Member Join Date: Jun 2002 Location: SF Bay Area, CA Posts: 7,824	How to read check engine light codes: - http://www.4crawler.com/4x4/CheapTri...CheckConnector There should be a plug for the O2 sensor someplace low on that side of the engine. And I think there is only one sensor on that vintage 22RE, don't think the post-cat sensors started until the '90s model 50-state smog engines. __________________ 1985 Toyota 4Runner SR-5, 22REC engine, dual t-cases, 4.88 gears, dual ARBs, 33x10.50 BFGs or 35x12.50 MTRs r.c.brown@ieee.org TruckEditor@tlca.org Project: 4Crawler 4Crawler OffRoad Gettin'Off 4WD Club

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11-12-2009, 05:52 PM	#5 (permalink)
yota4runna Registered User Join Date: Oct 2007 Location: Southern Ore. Posts: 325	Your 1987 truck came with one O2 sensor in the exhaust manifold, and it's a one-wire sensor. It plugs into a yellow connector that breaks out of the wiring harness going to the brake master cylinder cover: If you have two four-wire sensors in your truck, you may have a later model engine and/or exhaust system.