1994 Accord- Help diagnose O2 sensor (help me FIND it first!)
 

Hello, I am trying to get CLOSED LOOP working on my 1994 accord (2.2L N/A)

First, I need to find the o2 sensor. I know that sounds strange, but I simply cannot even locate it!!


Second, I checked the pinout and found the white/red wire From the ECU that should be the o2 sensor wire. Well, I am putting my multi meter on it, and it does not read the way it should for a closed loop operation (.005V-.995V). The engine does not use closed loop, from what I can tell.

I want to fix it. Where is the o2 sensor!!!

Re: 1994 Accord- Help diagnose O2 sensor (help me FIND it first!)
 

There is one on the exhaust manifold right below the head. You'll see wires coming out of the heat shield. And there should be one after the catalytic converter. Possibly one before it also.

Re: 1994 Accord- Help diagnose O2 sensor (help me FIND it first!)
 

Thank you sir, The O2 sensor wire signal (white/red) that is on the ECU, that is for the oxygen sensor in the manifold, right? That would make the most sense to me.

Right below the head, huh? Its raining right now, or I would go look again. I swear I looked three times even under the car twice and I cannot find a single oxygen sensor anywhere!!! Its like somebody removed them all.

Re: 1994 Accord- Help diagnose O2 sensor (help me FIND it first!)
 

Ok so I went out in the rain because I am excited to find this oxygen sensor.

Here is a picture so you can see what I see.


Yep, it looks like the oxygen sensor is missing!

Re: 1994 Accord- Help diagnose O2 sensor (help me FIND it first!)
 

Re: 1994 Accord- Help diagnose O2 sensor (help me FIND it first!)
 

I apologize, I seem to have misinformed you. I found a diagram online that showed an o2 sensor right on the manifold. But after looking at my car there isn't one there. There should be one before or after the catalytic converter. And don't quote me on this but the connector could be under the passenger seat. Sorry about that.

Re: 1994 Accord- Help diagnose O2 sensor (help me FIND it first!)
 

do you think an oxygen sensor will fit where that plug is? If so, I will simply install one there. It seems like a nice location.

that is, of course, if I cannot find the other one (actually removed). Or make it work. In other words, if I find out the one in the OEM location is bad or missing, I would rather install a new one right there off the manifold.

Re: 1994 Accord- Help diagnose O2 sensor (help me FIND it first!)
 

LX Accords:

https://honda-tech.com/attachment.ph...1&d=1259814409

EX Accords:

http://www.justanswer.com/uploads/JH...0_110928_c.jpg

Re: 1994 Accord- Help diagnose O2 sensor (help me FIND it first!)
 

My .02, are there any stored codes? Check, it only takes a paper clip. Next, again I'm old and almost blind but I think you have an exhaust manifold crack - not uncommon in this gen.

In the pic, there is a difference in the color on the #1 exhaust runner about where it would meet #2. Again it could be my bad eyes or the flash that makes it look that way.

Re: 1994 Accord- Help diagnose O2 sensor (help me FIND it first!)
 

Hello and thank you! I have been busy with exams so I havnt done anything at all except check the fluids for driving to school. I will take a closer look at the manifold- you may be right because I definitely hear some exhaust leaking from somewhere haha!

As to the paper clip- where do I stick this paper clip? on a camaro I would use the consult port by the steering wheel.
The car does not have any CEL that I can see- but that is probably because it is not working right. Does the paperclip actually try to flash the bulb in the dash? or is there one on the ECU? Because I doubt the dash bulb even works. To be honest. It probably has 15 codes lol! Nissan sr20det has the bulb for CEL right on the ECU so that always works.

Re: 1994 Accord- Help diagnose O2 sensor (help me FIND it first!)
 

more pictures of the exhaust manifold


When I start the engine, on tuesday at 8AM, I will check with my hand and feel for exhaust leaks if I remember. If not, then after my exams I will be sure to check.

Re: 1994 Accord- Help diagnose O2 sensor (help me FIND it first!)
 

i dunno if you found the o2 sensor but i have a 94 ex, and 94-95 only have one o2 sensor. mine was right before the catalytic converter. i just replaced my whole exhaust and header and only found one. the header i got had a plug for a second o2 sensor but i just plugged it with an oil drain plug because the OEM header didn't have one

Re: 1994 Accord- Help diagnose O2 sensor (help me FIND it first!)
 

it must be way up under there, because I cannot see it by just looking under the car from the sides. I will get it up on some ramps this weekend and take a really good look at what is going on under this car for sure.

In other news, there is no crack that I can tell in the exhaust manifold. I think it was just the picture. I started it and felt all around for any exhaust leaks but did not find a single one. I HEAR one, I think, but I have a feeling its much farther back, probably a gasket around the cat area. Its not very loud but I am accustomed to the sound from years of experience so I am fairly certain.

the ecu is out and ready to test continuity when I find the o2 sensor plug. I will report back with those findings when I get a look.

In OTHER other news, it looks like I will be picking up a car tomorrow, so I might not want to keep working on this one. I made a for sale thread already
http://hondamarketplace.com/showthread.php?t=3138930

if anyone is interested in it the way it sits I think I can part for about $1000 the entire car. If I re-wire everything the way I want and fix the O2 (replace the sensor of course) I will want $1100.
The car is a 5-speed, just throwing that out there.

Re: 1994 Accord- Help diagnose O2 sensor (help me FIND it first!)
 

Do you have the ex or not ? I'm guessing you do...if so it's under the car just before the cat. It's facing the sky in the downpipe.

Re: 1994 Accord- Help diagnose O2 sensor (help me FIND it first!)
 

can anybody show me the ECU pinout for my 1994 honda accord? Its got a manual transmission And I have a feeling maybe the neutral safety switch is stopping the car from starting. So I think I need to look for the wiring of the automatic transmission's wiring-

and then I got an idea. of course the automatic is gone and had a NSS, so the wiring off the previous shifter would probably be a great place to check for it. Its probably not hooked up.

In any case an ECU pinout would still be a huge help, I thought I had found one already but I cant find it now.

Re: 1994 Accord- Help diagnose O2 sensor (help me FIND it first!)
 

actually what I really need is an FSM. At this point, trying to figure out where all the relays are by using a multimeter is becoming tiring, especially when the vehicle is presenting intermittent wiring related symptoms, the most annoying difficult problems to diagnose IMO is wiring that behaves oddly. But so much fun! hahaha cant wait to get this all squared up.

Re: 1994 Accord- Help diagnose O2 sensor (help me FIND it first!)
 

So today I spent about 5-7 hours diagnosing and tracing the starter issue it had. Turns out the factory relay, wherever it is, wasnt doing a good job. It was intermittent so I wired my own in. Mounted it as factory looking as possible and used good solid heat shrink soldier connections for everything. Very strong, professional, and I even included an addition relay alternative ground for when and if I want to add a kill switch to the starter.

and as promised, pictures of it. detail and pictures.

I took lots of pictures but it was raining constantly and they came out blurry because it was kind of dark as well. this is the finished relay all nice and clean.

notice the ground loop around the bolt on the bracket I used. Its got soldier on it, its not just wrapped around the bolt- its a solid strong circular bit of wire thats been soldiered stiff and permanent. Now, you turn the key, and it starts perfectly every time. no more push button! lol yes it had a push button start.

also- its fused. I made sure to pull a 12V off the battery with an inline fuse just in case the unthinkable happens.

Re: 1994 Accord- Help diagnose O2 sensor (help me FIND it first!)
 

today I spent cleaning and wiring a few things. mostly cleaning everything as a basic first, the under side of the car, looking for any leaks.

It has presented with a new problem. maybe someone knows already: the power steering pump whines as if there is no fluid. But there IS fluid. its also leaking alittle power steering fluid. Usually when you get that whining noise, you just add fluid... but this is not the case here. I tried adding fluid and it just spilled over and kept whining. I am guessing there must be a blockage somewhere? It just started randomly today.


ALSO! the o2 sensor. there isnt one, its just plain missing. I checked every inch of the exhaust in the front half of the car and there is no oxygen sensor. not even a place for one.

Re: 1994 Accord- Help diagnose O2 sensor (help me FIND it first!)
 

front of the cat and the back half of the exhaust in these pics. No Oxygen sensor! Its not in the manifold, the extension, or the cat, before or after, no where.

Re: 1994 Accord- Help diagnose O2 sensor (help me FIND it first!)
 

At this point I am feeling like I want to do an entire overhaul. I think everything except the bottom end atm. Like pull the head, mill it, set the valve lash, replace the timing belt/tensioner/equipment, water pump, new distributor + o-ring and rotor and even pull apart the intake and clean out the egr passages (i read about that somewhere) I mean go through this engine and get it right.

But on the other hand, that is going to cost around $500 even doing all the work myself. And it runs fine the way it sits. I just dont know how long- how long until the water pump goes or the timing belt snaps? ahh decisions. I only have 1 week to get this done before summer classes start. I might order all the parts and get ready to do it- but wait until summer is done. Or, just go ahead and buy another car and sell this one like it sits. There is one I thought I was going to buy but now I am not sure. I will wait and see.

Re: 1994 Accord- Help diagnose O2 sensor (help me FIND it first!)
 

who did u get this car from?

Re: 1994 Accord- Help diagnose O2 sensor (help me FIND it first!)
 

my stepfather drove it for a few years then bought a truck and I got this. Its just a temporary daily driver for school. I thought about fixing it up and giving it back to him but he does not seem to need it. So Instead I want to sell it for him once I am done using it. While I have it... I am going to fix it up the best I can. Just how much $$ I want to spend? Especially unnecessarily. It might go another 50k before it needs a timing belt, whos to say.

Re: 1994 Accord- Help diagnose O2 sensor (help me FIND it first!)
 

How are you not throwing a check engine light, or have horrible gas mileage with those ports open and a lack of sensors?

Re: 1994 Accord- Help diagnose O2 sensor (help me FIND it first!)
 

You just need to find the oxygen sensor connector. Not really hard to do. Once you figure out what trim your car is. Then get either the exhaust manifold or exhaust downpipe that matches it.

Re: 1994 Accord- Help diagnose O2 sensor (help me FIND it first!)
 

theres a short piece of exhaust right before the cat. I might just take that off, and weld in a o2 bung. if I decide to drive it for much longer, that is.

the fuel economy is decent. under half a tank to get from orlando to here, so 230~ miles. it must be averaging around 28-30mpg.