[GREYLEGEND]

Before modding, make sure that your sensors are working the way they're supposed to first.

The TW sensor is important in that the ECU adjusts the A/F ratio according to temp. Make sure the ECU is seeing the correct temp by having a TW sensor within specs. My old one started to drift a bit and a new one helped the driveability and peppiness.

The next sensor is the O2 sensor. There are two of them and even though the ECU doesn't flash doesn't mean that they're still good. They need to be fast and responsive, As they get old they get slower and don't report back the efficiency of the combustion correctly. The ECU doesn't flash until they're really bad and by that time your performance is way down. So don't wait for the ECU flash.

I went thru this and what a difference!!!!!!

Reminds me of hi-end stereo setups where proper cables, clean contacts and proper setup can make more of a difference than an equipment upgrade!

 

[acc-unit]

im currently doing a tune-up ( spark plugs, wires, distributor cap and rotor) and i also wana change my sensors. could you please tell me where u ordered ur sensors, thanks

 

[GREYLEGEND]

In the US it's either keep your eyes on Ebay or just go to your local Autozone etc and order a couple of Bosch 11027.

 

[z00m]

how hard is it to check these sensors out and change them if necessary? i've been wanting to check mine out ever since i got the car, but i haven't ever gotten to it. maybe this will be the motivation i need i have a feeling my o2 sensors are shot because my gas mileage is like 16-17mpg city


edit: btw can u give me some more info on the tw sensor? i tried searching but no luck because tw is too short and sensor is too broad of a search. i already bookmarked 2 o2 sensors online from my local advance auto parts, they are 17 bucks a piece, is that a decent price?

 

[GREYLEGEND]

At $17 a piece, I'd say that's a very decent price.
You'll be getting a universal sensor but that's OK it's identical to the OEM style without the connector.

The proper way to see if the O2 sensor is good is to connect it to an oscilloscope it you have one that's handy. Do not connect it to an inexpensive multimeter or an analog multimeter. The impedance might be too low for the ECU and damage it. At $17 a piece why bother, change them if they have not been done within the last 50,000 miles or so.

The TW sensor is engine coolant temp sensor. or ECT in some books. That is not as critical as the O2 though. It's below and to the right of the distributor. You'll need to remove the distributor cap to access. I'm not sure if there are aftermarket ones to these.

The ECU will signal when both these sensors are totally shot but it has no way of knowing if they are within calibration.

CHANGING THE O2.
With a universal here's the easy way to do it if you haven't access to an O2 socket.

Get a deep socket 22mm or 7/8".
Cut off the wire coming from the O2 sensor on the car.
Using a breaker bar or cheater you should be able to get the O2 sensors off.
Don't crimp the wires to the old connectors yet.
You should be able to carefully tuck the wire on the new O2 sensor into the socket and then install. After it is installed, then crimp the wires together and heat shrink the connector to seal.

If you have access to an O2 socket then ignore the above.

 

[HotLegend87]

Where are the 02 sensors located anyway?

 

[z00m]

Where are the 02 sensors located anyway?

:werd: i'd like to see a pic if anyone can locate one

 

[GREYLEGEND]

http://www.honda.co.uk/owner/LegendCoupe/62sg000/6-28.pdf

 

[TurboViper]

:werd: i'd like to see a pic if anyone can locate one

look at your exhaust manifolds and they stick out with 1 wire on each manifold.

 

[z00m]

look at your exhaust manifolds and they stick out with 1 wire on each manifold.

ok ya, i found em in the past i had thought they were closer to the catalytic converter though for some reason

 

[HotLegend87]

Hrm, ok.....I was like zoom zoom and thought they were closer to the catalytic converter. Seems easy to replace now.

Is the 50,000 mile rule that GreyLegend cited a general rule in replacing O2 sensors or just something that he does?

 

[AndaHeart]

ok ya, i found em in the past i had thought they were closer to the catalytic converter though for some reason

ODB2 vehicles(i think 96+) have an o2 sensor downstream of the converter. not us. thankfully.

 

[GREYLEGEND]

i once relied on the ecu as telling me when the o2s are bad. i had a driveability problem that i just couldn't lick until the o2 was changed. that not only removed the driveability but across the board it was much better - smoother and more stable idle, no stalling or hesitation whatsoever, smoother operation, much smoother at higher revs.

Unlike some mfrs Acura/Honda never stated an interval for O2 replacement. Well ten years ago they were $200x2 and up and still are at the stealer. Acura would have upset a lot of people if they said to change them on a regular basis. They relied on the O2 failing outright and then triggering the ECU. I relied on that too but I relaize it's not good since a "good" O2 sensor will slowly get bad as I've since discovered. At the low prices and ease of changing today I'd consider them a tuneup item.

I never considered changing them before since I thought they were big $$$$.
Of the O2s I removed one was 10 years old and the other was since original. I suspect many of you have originals too.

On newer cars, that have OBD2, there is an O2 ahead of and after the cat. The ecu on these cars take the reading s after the cat to determine how good the cat is working and also compare readings to the one upstream. Essentially, newer cars have more "precise" and sensitive readings and require much more frequent O2 sensor replacement (also pricier) than our old G1s.

AT $17x2 , if you get a 1% fuel improvement over 50,000 miles you're even. Most people get much much better improvement than 1% over the 50,000 miles in addition to better driveability and performance. That's why I chose the 50,000 mile interval.

 

[z00m]

i once relied on the ecu as telling me when the o2s are bad. i had a driveability problem that i just couldn't lick until the o2 was changed. that not only removed the driveability but across the board it was much better - smoother and more stable idle, no stalling or hesitation whatsoever, smoother operation, much smoother at higher revs.

Unlike some mfrs Acura/Honda never stated an interval for O2 replacement. Well ten years ago they were $200x2 and up and still are at the stealer. Acura would have upset a lot of people if they said to change them on a regular basis. They relied on the O2 failing outright and then triggering the ECU. I relied on that too but I relaize it's not good since a "good" O2 sensor will slowly get bad as I've since discovered. At the low prices and ease of changing today I'd consider them a tuneup item.

I never considered changing them before since I thought they were big $$$$.
Of the O2s I removed one was 10 years old and the other was since original. I suspect many of you have originals too.

On newer cars, that have OBD2, there is an O2 ahead of and after the cat. The ecu on these cars take the reading s after the cat to determine how good the cat is working and also compare readings to the one upstream. Essentially, newer cars have more "precise" and sensitive readings and require much more frequent O2 sensor replacement (also pricier) than our old G1s.

AT $17x2 , if you get a 1% fuel improvement over 50,000 miles you're even. Most people get much much better improvement than 1% over the 50,000 miles in addition to better driveability and performance. That's why I chose the 50,000 mile interval.

ur the man grey great post, i plan on changin mine soon.

 

[JOEK]

i need some advise i have a 88 coupe running straight pipe if i let the car idle for 10 minutes or so then rev it i am getting blue smoke out the tail i have one old o2 sensor other than that all are well i had a code for that sensor in the distributor once i but my rpm needle had gotten stuck on the guage face and i reset the computer and fixed the needle and it stopped. but anyway i am burning no oil and no antifreeze i can figure whats wrong i have over $20000 invested in this car and the smoke is very embarassing i am this close to swaping the engine entirely but mine has only 93000 miles on it.