O2 Sensor/Check Engine Light

[truble64]

When I bought my Accord last month and took it to the garage, the mechanic said there was no O2 sensor on it, so he put one on. I picked the car up and drove it and the CHECK ENGINE LIGHT came on. The mechanic said it was OK to drive; I took it back and he disconnected the O2 sensor. No more check engine light. I took it back last week and he reconnected the O2 sensor...said he switched the wires. The CHECK ENGINE LIGHT is still coming on. Seems to only happen when the O2 sensor is connected.

Anyone have any ideas/suggestions for this problem????

Thanks.

[A18A]

doesn't sound like a very bright mechanic to me, I'm sure if your car had no O2 sensor the car would be noiser than normal. maybe he replaced it with a dud one? should check this http://www.3geez.com/forum/showthread.php?t=26342 to see if it really is the O2 sensor

[truble64]

Thanks. I'll print that out and take it to him. How do I know if the new O2 sensor is not good?

[Demon1024]

it'll throw the code for it. you can get a new one for like $30 at autoparts store and just have to splice the wires. it's odd you disconnect it and there isn't a code tho,weird.... check that code you get!

[Dr_Snooz]

Thanks. I'll print that out and take it to him. How do I know if the new O2 sensor is not good?

Do yourself a favor and take it to a different mechanic. The troubleshooting procedure is relatively simple, but does require some special tools like a voltmeter and a general mechanical aptitude. If you are up, let us know and we'll walk you further into it. If not, then remember that you need to find a different mechanic!

[truble64]

OK, so it flashes 01 LED, which means Oxygen sensor "A" has a defective circuit or unplugged/defective sensor.
So...when I take it back to the mechanic (yes, same one) and tell him this, can he check the O2 sensor to see if it's defective?? And by 'defective circuit', what does that mean? The mechanic said when he reconnected it, he switched the wires this time.

[Demon1024]

when one or both sensors are dis/connected does the light come on?

unless you know this guy and he's working for free do yourself a favor and go out and buy a repair manual and a wrench set.while your out buy 1 or 2 o2 sensors(however many you have) a 22mm(i think)wrench and change them. unless you know the last time they were changed. You'll have a set of tools , possibly better m.p.g, and a sense of self satisfaction all for less than the price of 2 hours at a shop
Defective= something wrong with it. lose connection, broken wire, failed component

[Dr_Snooz]

Start by inspecting your fuel pressure regulator (dash pot looking thing on the driver's side of the fuel rail). Attach a pressure gauge to the service port on the fuel filter (small bolt on top I believe). Inspect the pressure with the engine idling and the vacuum hose disconnected from the regulator. Pressure should be between 36 and 41 psi and the pressure should rise when you disconnect the vacuum hose. If the pressure is out of spec, you're looking at a fuel pump or regulator issue (or possibly something funky with your lines). This involves separate diagnostic procedures, so let us know if you need to check those.

If that checks out, disconnect your sensors and measure the voltage between the sensor terminals and body ground with the engine running and warmed up. The voltage should be 0.6V above 5k rpm and below 0.4V when the throttle is released quickly from 5k rpm. If they are out of spec, replace. If all this checks out, then you will need some specialized diagnostic equipment from Honda, ie: take it to a dealer for diagnosis.

Let us know what you turn up and good luck.

[truble64]

The check engine light doesn't come on when the sensor is unplugged. Only when it's connected. I'm kind of out of luck, cause I'm a girl and not mechanically inclined, so I have to take it to a garage. I have an appointment Friday...

[Demon1024]

thats why your names trouble! sorry lol
hope you get it fixed.

[truble64]

Actually....TROUBLE is a nickname my Dad gave me when I was little.
Thanks for the info guys. Hopefully I can get it fixed correctly. I just wish I could do some of this stuff myself...

[Demon1024]

you can read up and use leverage on hard bolts (cheater bars) unless your afraid of getting dirty, thats hard to keep from happening doing most stuff. it all washes off tho

[truble64]

I wouldn't mind the getting dirty part...it's the knowing how to do stuff part that's the problem.

[xxxfrankensteinxxx]

sounds like you want to work on cars but are just to worried about messing something up, dont worry to much as long as you have a good head on your shoulders hell you dont even need that ive seen some fucking dumbass mechanics, just learn about cars if you car study them and take your time and tinker or dont be afraid to ask on here for help:rockon:

[truble64]

OK, now I'm more confused than before. Someone just told me that there are more than one O2 sensors on the 89 Accord. Can someone verify this for me???

Also, someone else said there are 5 different sensors, so am I using the right one???

:stupid:

[ghettogeddy]

what model is it is it carbed or fi

[Nafs Asdf]

I'd guess EFI since the first post is all about the CEL

[ghettogeddy]

I'd guess EFI since the first post is all about the CEL

hahahaha im slow this morning lol


ya you have 2 o2's

[Oldblueaccord]

OK, now I'm more confused than before. Someone just told me that there are more than one O2 sensors on the 89 Accord. Can someone verify this for me???

Also, someone else said there are 5 different sensors, so am I using the right one???

:stupid:

There are two Oxygen sensors on most of the fuel injection cars. If you look down at your exhaust manifold you will see where they are plugged in. In between the radiator fans and the exhaust manifold you will see the wires. It is possible the plugs are switched maybe and why you see the code only when one is hooked up. Just a guess. I think there are called A and B. Also it is fine to use the generic O2 sensor in our aplication it is usually much cheaper.

http://tbn0.google.com/images?q=tbn:fR_9aWPte7eZPM:http://k43.pbase.com/u18


And just to add from before there not really that easy to test unless you have a scan moniter to test for or an ocilliscope. There output "swings" from rich to lean pretty quickly so a regualer volt meter is not that accurite.

http://www.myscantool.com/images/screenshots/proscan4-0/OxygenSensor.gif

[Oldblueaccord]

http://www.aa1car.com/library/o2sensor.htm

heres the whole shee bang if anyone wants to learn about it.



wp

[truble64]

It's FI

[ecogabriel]

Hello,

(I hope someone would look at this thread)

I have a similar problem like the one posted here.

1986 Accord LX-i (fuel injected). I was looking to solve a slightly rough idle problem; I unplugged the O2 sensor -(1986-87 models came with only one sensor and 88-89s used two sensors as both have different exhaust manifolds). So mine has only one sensor which I checked for function. :violin:
It is probably gone as the sensor's generated voltage went negative when idling. :gun:
Not a big deal to get a replacement; I actually thought on getting a "universal" type and splice the connector into the new one.

But the funny thing is that the ENGINE light (called PGM-FI) does not come on with the sensor unplugged. Funny enough, unplugging or plugging the sensor seems to have no noticeable effect on how the car runs. I bet that once it is running hot (close loop) the engine should run slightly different when the O2 sensor input is lost -it should go to default mode.

Thinking the ECU might be the problem, I started unplugging other sensors. Engine coolant temperature unplugged: ENGINE LIGHT ON. And with this one unplugged you can feel that the engine run slightly different.
Air intake temperature unplugged: ENGINE LIGHT ON
EGR valve lift sensor unplugged: ENGINE LIGHT ON
EGR vacuum line unplugged: ENGINE LIGHT ON

So, I am not sure the ECU is the problem (although it cannot be completely ruled out). It recognized when it lost every of the other sensors listed above. And in the past it would also acknowledge O2 failure (see note below).

Any ideas, anyone?

What I suspect is that somewhere between the O2 sensor and the ECU the wiring is somehow grounding itself or offering some resistance that the ECU "reads" as the O2 sensor being present (even if it is, or if it is not).
Unless other suggestion, I would use a spare wire from the O2 sensor to where it should be plugged into the ECU and see what happens. Alternatively, I could try to measure the wire resistance between the ECU and the O2 connector.

Other suggestions/ideas/comments will be greatly appreciated.

I love how well the little jap runs. It used to piss oil from every single place it could but after replacing ALL the motor seals (yeap, including the REAR main seal...) and the oil filter base gasket the leaks are gone... 22 years old... and running fine... what a machine!


(NOte: when I first got the car it has a timing belt problem and the ECU would signal an O2 code because the car would idle erratic after a couple of minutes and in the end it would die after 4-5 minutes, but right before that happened it would signal a O2 code. All those problems were gone after replacing the timing belt and setting it up correctly -the mark with the T beside it... amazingly, the belt had been replaced by... A DEALER!!! and I have the receipt for it.)