Hey guys just got my swap pretty much done. I have a 91 crx si with a JDM B16a crx with matching trans. Unfort I don’t have a stock exhaust manifold for this particular motor and I know you need to run 2 O2 sensors for this thing to run right. Essentially I’d like to run it with no check engine light and have it run as efficient as possible, if someone is selling an oem exhaust manifold or has a solution to this issue that would be awesome.

 

are you running the obdo ecu?

 

You only need one o2 sensor if still obd0, or converted to obd1. I can't imagine you converted to obd2, that would be extra work for nothing.

 

sorry i didn’t mention it yes I’m still running an obd0 ecu

 

Really you only 1? I’ve read that 1 sensor is for reading certain cylinders while the 2 second sensor monitors the other 2. Which one should I run? And do you have a part number where I can buy the sensor itself?

 

Does anyone have an oem B16a exhaust manifold for sale?

 

It could take a while to find one of those. Any B16 or B18 exhaust should bolt to the block, though the back end of the downpipe may need modification. Refer to link:
https://www.ek9.org/index.php?thread...uestion.50616/

 

if you find the rare 88-91 ef sir b16 manifold the 02 sensor location would be on the header itself

but more than likely what you might have better lucking finding is the 99-00 honda civic b16 si manifold with the o2 sensor
location on the bottom of the header downpipe

also the acura integras from 90-01 would have a header that will work out for you also

and as far as getting the sensor i would just go to a parts store like autozone for example and buy one
and when you order it you would ask for a 1990 honda crx si o2 sensor the 1.6 this o2 sensor is the one wire one youll need
if you plan on staying obdo

it will work just fine with your b16 motor ^_-

 

One thing to keep in mind, many of the aftermarket headers have the O2 sensors placed further away from the head. Combine this with the thin wall tubing vs the stock cast iron construction results in heat loss in the exhaust prior to the flow reaching the O2 sensors. I chased an issue for a few months where the car would bog or stumble during cooler weather but would run just fine at wide open throttle or if it was warm outside. Because the OBD0 O2 sensors are one wire and contain no heater element within them, they rely on the heat from the exahust flow to keep them at nominal operating temperatures. Because the heat was escaping, the sensors were reading incorrectly. I ended up wrapping my header which solved the problem but you can also use 4 wire O2 sensors but will need to wire in a relay to power them.

 

yes no luck so far with finding one /: but thank you

 

thats very interesting. I have a 90-91 integra exhaust manifold, the o2 sensor is actually on an adapter pipe right after the header itself. I’m curious cause I know you need 2 sensors to run the B16a properly so, my question is if I run this stock 90-91 integra header with a stock 90-91 crx si o2 sensor it will work fine on a JDM B16a that requires two 02 sensors? If I run 1 sensor would it cause a check engine light? Really don’t want to have the cel on

 

Very cool, that makes a ton of sense! Here’s my exact issue. I have a 91 crx si with a JDM B16a and matching cable trans. I was using an aftermarket exhaust manifold (PLM) which was 4-2-1 setup. I had one o2 sensor at the end of the headers and the second only a few inches past the first In the test pipe. The car would start and idle high as usual at first start then proceed to drop but stay around 1k. After driving for a few minutes the check engine light comes on and the car starts to bog out on acceleration. Never stalls but runs like crap. Any ideas on how to run my oxygen sensors? Is one really needed?