BMC

Ok so here is the deal. I have an 87 4runner with a 22re and a 5 speed. I recently installed an LCE header, a high flow cat and a 40 series flowmaster. Ever since the new exhaust system has been installed my check engine light comes on and off when im driving at a steady rpm, mainly on the highway in 5th gear. I was pretty sure it had something to do with the oxygen sensors new location so I ran a test on it and the code came up as oxygen sensor. I really didnt think there was anything wrong with the sensor itself because it worked just fine before and i didn't bang it around when it was moved to its new location. So after a couple months of driving around with the light coming on and off i decided to stick a new o2 sensor in there in hope that it would fix the problem. Well it didnt. So i think with the oxygen sensor moved back so far from its original location, and the high flow cat, its just not building up enough back pressure to keep it hot enough to get a correct reading. Anybody else have this problem with the LCE header? Any thoughts or opinions would be great. I really dont know what to do.

Thanks, Bryan

DeathCougar

iTrader: (23)

its the same problem with all LCE headers, and the O2 sensor position. Normal systems would have a 4 wire sensor, with a preheat circuit. Ours doesn't. I had the exact same problem in my 87. A new factory o2 sensor fixed the problem, but I suspect it will come back eventually.

4runnerAndy

I am new to this site. I believe this is the closest thread to what I am looking for. I also have a 1987 4runner with the 22RE but I bought this vehicle some time ago as a builder. The engine and most of the components were in the trunk in pieces. I've rebuilt the engine and installed it but I have some electrical connectors with no home. In my search I noticed that I don't have an Ox sensor anywhere. I can't find anything that tells me where the sensor was originally installed. It is not by the cat like on my friend's 89. Anybody have a pic where this should go? I may have parts from different models since I did have extra duplicate parts. I can drive it but also get the "check engine" light at the stedy high RPMs.
Also SAS conversion difficulty and cons?

Junkers88

Andy. On my 86 22re the O2 sensor was on the exhaust manifold as far as I can remember. You may need to make sure you have the correct year manifold.

Oh and on the SAS question you should probably do a search. It's been covered a lot here.

kiyobrown

My 87 had it in the manifold as well. I put on an LCE header, and relocated to around the crossmember level. Threw an o2 sensor code (code 5) put a new one in, no more code. I believe 89 was the first year they moved them down before the cat, but I could be wrong.

4runnerAndy

Ok, So if I have the wrong manifold i will probably get a muffler piece that would locate it by the cat. Yes, I'm cheap. Where does the wire for the sensor come from? Is it one of those homeless square connectors in the engine harness? Once I find this wire (being otimistic), would'nt I have the same problem as BMC? If these are not heated sensors, I may need to weld a fitting for the sensor closer to the manifold. Any thoughts? Thanks.

Junkers88

If you get the right manifold there will be a place for the O2 sensor in the manifold. I think it was like 2 bolts but I haven't had the 86 for a while. Then you need the connector pipe from the manifold to the cat. Best bet would be to hit a junk yard and find the right manifold. Buy the manifold and connector pipe and if it still has the O2 in it then trace the wires so you know where it all hooks up.

This is one of the biggest problems with buying something that has all the parts in the trunk but it can be overcome. And it makes you a better owner since you know all of this stuff from fighting with it for a while. We've all been there in one fashion or another.

Welcome to YT!

kiyobrown

No, 87's are a one wire sensor, no heating or any of that. I now have mine relocated down below. the original plug was under the brake booster and the cruise actuator, if you have one. A yellow, round plug. If that wire has been cut, you will see it has copper wire in the middle, black sheathing, shielding wire, gray sheathing. If you rewire a new plug (or j yard donor) make sure you don't have shielding wire with your signal wire. You can wire it above or below, whichever is easier for you to place a new sensor.

And find someone that lives close to you with a stock motor in a year close to yours. We have noticed a lot of "PO Tinkering" when you can compare side by side motors.

Teuf

I thought the 02sensor fed up under the drivers seat to a plug, ? and how long do they last?

kiyobrown

K, they must have switched in 88 if tuef has the sensor in the connector pipe. 87 and before were in the manifold itself. Mine was the original at 190k and would have still worked fine if I would have left the leaky stock manifold on there.

Bosch says 50k, but that's probably so you can buy another Bosch sensor!

toyota4x4907

'88

kiyobrown

one step ahead of you.

AzStorm

I had the same problem on my '91 22re after installing the LCE header and full exhaust.

I replaced the 02 sensor and the knock sensor and havent had a problem since.
The truck had 155k miles so it was probably due anyway.

Etype R

So are you guys just buying new single wire O2 sensors? What brand has been working well for everyone? I was going to install a 4 wire heated sensor, but if a new single fixes it I will do that instead

kiyobrown

Single wire denso. I also double checked the extended harness wire, and found shielding wire had gotten in with the signal wire. Fixed connections, new o2 sensor, no problems.

4runnerAndy

I scored! Found a wrecked 89 donor 4runner. I will use the pipe piece from muffler to cat. Kiyobrown says not to use shielded wire to extend the sensor pigatail/harness. Any reason why? I've worked in aircraft harnesses and shielding has always been preferred unless the shielding is not gronded or makes contact with the signal wires. I wanted to keep the vehicle as original as possible but seems like finding parts (used) for the classic Toyota 4runners is close to impossible hense the need to keep the newer exhaust.

kiyobrown

No its fine to used shiielded wire, just don't have the shielded wire IN WITH your sensor wire. I found some in my connection, could have messed up the signals. But since I fixed that and replaced the sensor at the same time, we'll never know which one (or both) solved the problem.

tim a.

Any good muffler shop can install an 02 boss.My 92 rusted out the conecter pipe where the manifold runs to muffler,right at the 02 sensor.I had muffler shop splice into the header tubes with 2 inch pipe and a new bung,topped of with a new 02 from ebay{guy said it was an new ngk,no box,but had right connector,maybe chinee',but works}.Runs great

d71889b

i've never had any problems finding used parts? check out craigslist or ebay. i have a 93' and my buddy has a 94' ( 22re ) and neither of us have had any problems throwing codes after we put headers on. no cats either. i have a pacesetter full system and he has the lce full system. btw they are both the 3 wire sensors. i had a 91' 22re ext cab and if i remember correctly it had the 02 sensor on the manifold. it had a header as well. idk what kind but it had a spot for the 02 sensor on the header ( if i remember correctly it may have been my 87' 4runner i'm thinking of which makes more sense )

4runnerAndy

Picking a new O2 senson today since donor vehicle has heated sensor. New sensor specs say pigtail is 20" long. Just hope this reaches to the new sensor location. Might just have to get the wire stretcher