mcarrico2

I am in the process of rebuilding a 22re for my 89 truck that I picked up. It has two Sensors on it....one right on the manifold and then one more downstream before the Cat....quite strange. All I see on this site is sensors after the cat. I also have the part numbers off of these but cannot seem to locate them. The one on the manifold is a single wire. The one downstream is a 4 wire one....is anyone familiar with this??

4wd4fun

should have one sensor in front of the cat. if you have one on the manifold, it's not supposed to be there a previous owner probably put a carb'd exhaust manifol on it for some dumb reason. find the right manifold and downpipe for a 22re

mcarrico2

I am not suprised....this truck is a joke.....It has been through WW2....LoL I actually ordered a header from LCE so I should be ok with that I guess. Just go with the 4 wire I assume? I am cutting the cat off too.....No Smog limitations where I live.

4wd4fun

have you traced the wire from the manifold sensor to see if it goes anywhere?

but the 4 wire by the converter is fine for yours. 4 wire has a heater so it starts working sooner so it helps the computer sooner. some have another sensor after the cat but its there mostly to tell the ecu if the converter is working

SoCal

California emissions run two O2 sensors. Not sure on the locations though.

skypilot

iTrader: (1)

I have an '88. The one under your seat is the location for your truck. The spot in the exhaust manifold is for the 1986 truck (one wire), and should be blocked off. You have a replacement exhaust manifold or a 1986 vintage unit on your engine, since its one part number for all years and models.

It should be a two wire model O2 sensor under the drivers seat. In 1990 it went to 4 wire, unless yours is a very late production model it might have a 4 wire, but I sincerely doubt it.

4wd4fun

som ca do, some don't. one is right in front of the cat and that's on all, the other is behind the cat / before the muffle and that's not on all.

4wd4fun

not necessarily.

RE engines may have a different exhaust manifold than the R's and most post 85 EFI should have lacked the casting on the manifold for the sensor as well as should not have the siamesed ports (2 & 3) to feed the o2 sensor mixed exhaust to the o2. 22r's were, from what i've heard, the "standard" engines on pickups through 1992 however most dealers ordered 22re's for stock and only special ordered 22r's on request.


i have an 88 carb'd intake and its corresponding exhaust manifold in my garage (as well as the carb and fuel pump and distributor if you'd like to buy) and it has the casting on the manifold for the sensor but it's not drilled out as that engine had the o2 heated before the converter... at least on the truck it was pulled from. so that manifold was available after 86 on carb'd engines. so much for "vintage".

my 88 has a 4 wire.

edit- nevermind, just checked and it's 2 wire.

son_of_a_lc

the cal trucks have 2 o2 sensors, one pre cat and one post cat, they are also 4 wire sensors, not three like the federal emissions.

It sounds like you have a pre 89 manifold with. These had the sensor on the manifold.

If this sensor is hooked into your harness then im stumped. But if its not hooked up then i wouldnt worry about it, the only one thats important is the one downstream.

Zelephant

I have an '89. My O2 is under the drivers seat, but it is definitely 4-wire; I know because I had to solder in an extension. However, I also have a manifold with an O2 sensor in it, but the wire has a dead plug on the end. I assume someone put in an older manifold, or maybe even swapped motors somewhere along the line, who knows?

mcarrico2

Well my truck is at a friends house where we are rebuilding the engine. I will look and trace the single wire plug tomorrow afternoon. I do know for a fact it was plugged up when I removed the engine as was the 4 wire one. I will take pics and all just incase it is rigged up somehow.

benchernif

Just check and see which state the truck was manufactured/sold. If it's California then it's going to have 2 Oxygen sensors.

My 3VZE does. One pre-cat and one post-cat.

Ben

mcarrico2

Well I loooked at the connector and obviously it is rigged up....there is a green and white wire in some rigged connnector that went to the sensor on the manifold....I haven't traced it all the way through the wiring harness yet. I will next week.