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The Hondata Kpro supports a wideband primary O2 sensor. However, Civics from 2001 to 2003 (apart from the HX) came with narrowband O2 sensors. Only the HX model and Civics from 2004 to 2005 came with the wideband primary.

I am trying to install a newer wideband sensor from 04-05 on my 2002 LX Civic (D17 motor). Has anybody tried, or know how to convert the narrowband wiring for use with a wideband sensor? Accordring to the pin diagrams from Hondata, the harnesses look identical accross 2001 to 2005 apart from the location of the secondary O2 sensor. Most importantly, primary O2 sensor wires are the same.

A heated narrowband sensor uses 4 wires. 1 signal voltage. 1 ground. 2 for heating of the sensor. So the factory harness has 4 wires. A wideband sensor has 5 wires, what to do with the extra wire? Provided the other four wires are the same. Are they the same?

 
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Very good post! I have been talking to Doug about this. The problem is, the relays are different. I plan to do the wiring conversion in the very near future and use an 04-05 sensor. I'm going to test it out and see if it works. I will post up details when I figure it out.

 
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so if you have an 04-05 and run an afr guage you wont get the bouncy narrowband type readings?

 
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the bouncy readings you see is like that on all honda's and acura's running in closed loop oeration. Its what gives it the economy feature of saving gas.

However when you floor it and go into wide open throttle it looks open and doesnt move back and forth. It stays at whatever it is such as if it was running rich or lean

 
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I don't believe the air/fuel gauge will read a wideband signal. Not to mention, the calibration won't be correct. Best to use a sensor that will work with whatever gauge you're using. PLX now offers the SM-AFR with a digital gauge for less than 300. Very nice unit.

 
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i checked out the plx unit. does the wideband sensor just replace the primary oem sensor?

 
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Yeah, I was looking into the 04-05 sensor aswell. Good to know I'm not the only one trying this conversion.

Found this for the K20 swap.
http://www.xproductionz.com/k20swap/k20swap.html

There is a section for the oxygen sensor wiring and relay. Since it's essentially the same ECU we are working with, this may be useful. I'm still trying to make sense of it as of now.

I look forward to the results of your testing. I'll post whatever I can figure out.

 
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Ok, let me explain a little about k pro and o2 sensors.

You don't even NEED an o2 sensor to run kpro. You can disable closed loop and run strictly off the map, you just need to be tuned. The kpro doesn't require use of oxygen sensors at all. You use oxygen sensors if you WANT to run in closed loop OUTSIDE of boost or simply to monitor your a/f ratios.

You can also use o2 sensors for lean protection which will cause fuel cut if it sees a certain a/f ratio.

The trick comes in with what sensor you're supposed to use. According to Hondata, my PLX won't run closed loop because of the map used. I'm not sure whether you can use it on different maps instead or not....

 
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The plx sensor needs the unit itself and will not replace the oem primary sensor. The onyl sensor you can use for the primary is the STOCK sensor. You cannot just wire any wideband sensor into the ecu, it must have it's own separate controler such as the PLX Devices unit.

The US and Japanese K series engines use a wideband front oxygen sensor capable of maintaining a steady accurate air/fuel ratio even under wide open throttle. The stock O2 sensor is wide band and can read from 11.5:1 to 30:1 A/F ratios.

Let me try to explain it. Narrow band o2 sensors work by the difference in oxygen levels between the exhaust gas and outside air creating a voltage difference across a ZrO2 Nernst cell. They don't require any power to produce an output, and the ECU can just read the voltage from the narrow band sensor.

You gotta remember that wideband o2 sensors add an oxygen pump cell and reference cell with heater to the Nernst cell. A controller regulates the current through the oxygen pump cell and also the heater current. The ECU cannot read a wideband sensor and there must use a wideband controller to run the o2 sensor. The wideband o2 sensor does not produce a voltage, but rather the amount of current through the oxygen cell tells us the AF ratio. The amount of current varies by o2 sensor but some are as low as +- 1mA full scale.

The difficulty is that the wideband controller must be matched to the o2 sensor. The reason is that the amount of cell current and heater current is critical for the life of the o2 sensor. Cold start current regulation is very important and it actually is possible to destroy an o2 sensor in a single cold start. This is why it is not recommend that people wire in anything at all to the o2 sensor wiring. An external AF meter will not read the wideband o2 correctly, and more than likely will consume enough current to throw off the reading drastically. Swapping o2 sensors is equally as hazardous.

To replace the RSX o2-04 sensor you will need to find an exact equivalent o2 sensor, as the wideband controller electronics is integral with the ECU and cannot be replaced nor altered. The other options would be to run a cheap narrowband o2 sensor, and use the secondary o2 sensor input for closed loop (which is now available in KManager), or to use an external wideband controller which uses a cheaper wideband sensor and feed the analog output from it into the secondary o2 sensor input as above. That way you can datalog.

Heres an example. You can basically take the output wire of a AEM UEGO wideband gauge/controller, and wire it to the secondary o2 input wire and kpro will run closed loop according to those readouts. OR..... use a generic "cheap" narrowband and plug it up into the secondary o2 plug, and have kpro run closed loop according to that.

However there is a slight problem as of now. You need to run a PRA calibration. Any other calibration wont let you properly run this.

This goes the same for you andyman. If you wanna run your PLX you have to take your output from the plx and wire it into the secondary o2 sensor input on the ecu AND run the pra calibration if you wish to do so

 
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+1 on the info. so ill just need a new o2 sensor bung and weld it in the exhaust pipe before the cat

 
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Right, this was what I was told, only certain maps allow you to use this feature. What car does the pra come out of?

 
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you can use any of the map (calibration) that came from a pra ecu.

You dont have to use a pra ecu.. but the pra is the euro type r ecu..

the only bad thing i see this is that lets say you already got a dyno tune using a prc calibration. If you use a pra calibration then you essentially gotta get your car redynoed just to use an aftermarket wideband

 
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I'm planning on wiring in a honda wideband for lean protection more than anything.

 
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How about this. Can I wire a PLX SM-AFR or M-300 wideband controlers wideband outpout to the primary oxygen sensor on the ECU then set the lambda/voltage conversion in the Hondata software to match. This way I can data log the wideband lambda.

 
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According to what I've heard, yes, you can, but only with the PRA calibration as stated above.

Good news. I spent all evening yesterday tracing wiring diagrams of the 01-03 civic HX (uses a primary wideband o2 sensor) and also traced the rsx wiring for the PHO2S (AFRS (factory Honda wideband)) and I have found the correct wiring schematics to run a factory Honda wideband sensor in an 01-03 dx, lx or ex. A relay must be wired in but I have created a wiring diagram on EXACTLY how it needs to be done.

I tried using a few resources like xproductonz o2 sensor wiring for k swaps but it didn't help much as you're already using a conversion harness and an 01-03 dx, lx, ex wiring harness is completely different. I do appreciate his response in trying to help though.

If anyone wants a copy of it just pm me with your email addy and I'll email it to you.

Remember, this diagram is intended for use with 01-03 dx, lx, ex. Pretty much any other chassis you use kpro in will already have the wiring and wideband sensor in place. If you have an 04-05 civic (any model), you will already have the wideband in the primary spot. Oh yeah, if you plan to pick up a sensor, the cheapest I found was from majestic honda for a little over 100 and it was for an 04-05 civic. Just make sure whatever you buy is an AIR FUEL SENSOR, not just a plain "oxygen sensor".

And for those who have no idea what lean protection is, its one of the most useful options you can have when it comes to protecting your engine.

Detonation from lean conditions is one of the number one causes of engine failure in boosted hondas. By running this sensor and enabling this feature, you can safeguard from hitting lean spots and prevent blowing headgaskets and destroying engines. This just adds to the list of why I would choose kpro over aem.

 
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You sir, have PM.

 
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Replied, being as you are using the xfc, this will be of absolutely no use to you. You would have to pick up an ecu for an 04-05 civic ex, then you could use the wideband but it still wouldn't really benefit you being as you have no equipment to really use it with.

 
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Yet. Gotta plan for the future man. In 6-8 months, the XFC comes out and a new, built, engine with kpro goes in.

 
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PCS has the capability to autotune through a wideband already I thought?

 
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great thread!

 
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I don't see anywhere in the manual where it can auto-tune from a wideband. It can accept and process the signal, but I don't think its a matter of install wideband, run PCS autoconfig for wideband, instant tune, rip up and down street at 6K rpms on 15 psi. Then again I've only read the manual once and haven't installed it yet.

Section 9.2.5 Air Fuel Ratio Input (from the PCS manual)

The XFC has two wideband functions for the AFR sensor that measures the oxygen in the engine exhaust. The wideband oxygen sensors are used with a controller to give a broader range of output signal (0-5v) rather than the stock narrowband output signal (0-1.2v).

Question is: Will it the stock D7 ECU take a stock Honda wideband sensor in addition to the two narrowband that are already there? And if so, how do you wire it in?

I don't know.

 
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pm'ed

 
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No, like I said, if you have an ecu from 01-03 that isn't an hx, the outputs on the ecu aren't functional, the pins aren't even there, you can't wire it in. Maybe you can datalog with the pcs and a wideband but not with this sensor.

 
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Gotcha. Didn't think so, otherwise folks would have been all over the stock Honda wideband for a while now. Can I still get the wiring diagram for my future use?