Performing Honda K24a3/AST5 6spd Conversion

[lookforjoe]

Spent time on the car this weekend, cleaning up odds & ends on my list.

Re-covered the accessory gauge panel with a thinner vinyl leatherette - the original one I made was too 'thick" & just didn't look right (no pic)
Got an O2 failure code on Friday (P1157), so I removed the trunk panel (again) and replaced it with a New Denso unit 234-9066

Removed the Dalla wing, and compounded & polished the trunk lid. I had not done a perfect job last year when I installed it

 

[carl]

I know this drill, one spends so much time with one car (your Datsun) that one needs a break.....working on one's other car. I do this all the time.

 

[lookforjoe]

So, I don't think the X1/9 wants to leave me. It seems to be creating issues. I left the house to drive it to work at 6 this morning, and when I left the side road to join the 4 lane road that leaves town, I went over some loose stones/gravel as I made the turn. Within about 20 seconds there was some noises & visible smoke from the engine bay, so I pulled to the shoulder. A stone chip had got into the drive belt & sliced 2 ribs off, which were now flapping around the AC compressor & smoking as it was being wedged inbetween the moving pulleys, etc. I turned around & went straight home - I actually thought the belt was gone, so I wanted to get home before the engine warmed up and/or the battery died.

Looking at it closely, I then saw that 4 ribs were still intact, so I pulled out the torn strand from between the pulleys. I have a spare belt so I put that in the car with the lever tool & drove to work. Just glad that didn't happen on the way to NH

 

[JKIDD]

So, I don't think the X1/9 wants to leave me. It seems to be creating issues. I left the house to drive it to work at 6 this morning, and when I left the side road to join the 4 lane road that leaves town, I went over some loose stones/gravel as I made the turn. Within about 20 seconds there was some noises & visible smoke from the engine bay, so I pulled to the shoulder. A stone chip had got into the drive belt & sliced 2 ribs off, which were now flapping around the AC compressor & smoking as it was being wedged inbetween the moving pulleys, etc. I turned around & went straight home - I actually thought the belt was gone, so I wanted to get home before the engine warmed up and/or the battery died.

Looking at it closely, I then saw that 4 ribs were still intact, so I pulled out the torn strand from between the pulleys. I have a spare belt so I put that in the car with the lever tool & drove to work. Just glad that didn't happen on the way to NH

It's jealousy now that you're driving the Z...

 

[lookforjoe]

The inboard ribs were what went away (6PK1670). I loosened the tensioner, and moved the belt to the middle of the AC clutch. Only 15 miles or so to get home, so I'll just drive it gently & keep the revs low(ish)

 

[Bjorn Nilson]

You promised to take her with you to your grave. Remember? -She is fighting back.

 

[lookforjoe]

shot with the Mrs. Have to do another, she was whimpering too much, she is a good sport though

put a new belt (6PK1670) and tension idler (Honda metal tensioner 31180PNA003) on. The stripping belt ate the edge of the idler

all better.

On the way to NH FFO. I'm staying overnight in MA to break up the drive. So far, I have been caught in a sudden deluge, and a bird committed suicide on the front of the car - thankfully it wasn't a large one & I was going under 80 at the time..

Tail end of it - I pulled under an overpass & put the targa lid on

Deluge only lasted about 5min, then it cleared up. I drove around 80ish, and that blow dried the car quite nicely. It's so nice at that speed, rpms are low, plenty of torque for rapid acceleration if needed

 

[KBabcock]

Careful of a scorned ex lover, this was its equivelent of a bunny in a pot.

 

[lookforjoe]

Ongoing System WBO2 failures.

86X suggested a resistor mod

I know it's a different ECU but perhaps it will be of some help.

View attachment 78986

If a resistor is added to the O2 sensor on any other ECU, then hopefully the O2 function can be recalibrated in the ECU/O2 controller because the added resistance will throw off its accuracy a little.

EMU is the EMS? I don't know how that insert ( resistor btwn 5+ and WBO Vs) relates to a factory ECU WBO2 circuit. I'll have to research it. Mine seems to get burned out, the signal to the ECU is what goes away. I can't recall the error code offhand, it's a Honda-specific code, not the 133 -137 lean or slow response codes

What is the "WBO Vs" input? O2 Voltage signal from the sensor?

EDIT: need to move this part of the conversation to the K24 build thread, I'm not going to be able to find it down the road, since this thread pertains to the Body Mods

So I don't loose track - reference threads on KTuner regarding the (aftermarket) WBO2 input :

found a thread I started on KTuner where he told me about the display options for the WBO2 overlay. Another poster asking about graphing the WBO2 controller input.

List of O2 replacements

'05 RSX ECU 37820-PND-A63. JDM '05 K24A3.

I have installed:
Bosch 15482 (actually repackaged Denso) (Sept. 2018)
Denso 234-4454 (July 2021)
KAX 234-9066 (Dec 2021),
Denso 234-9066 (Jun 2023)
Finally a Honda packaged 36531-RBB-003 (Nov 2023)

They all fail the same way, with a Honda-Specific error to do with the output signal missing from the O2 sensor P1172, and/or P1157. I have verified several times that each individual wire from the EMS to the 4 pole WBO2 plug is intact.

A fellow on K20a.org said he had seen O2 failures due to ELD malfunction, but that was killing the O2 heater circuit, which is not the failure I see.

 

[Rupunzell]

Ongoing System WBO2 failures.

List of O2 replacements

'05 RSX ECU 37820-PND-A63. JDM '05 K24A3.

I have installed:
Bosch 15482 (actually repackaged Denso) (Sept. 2018)
Denso 234-4454 (July 2021)
KAX 234-9066 (Dec 2021),
Denso 234-9066 (Jun 2023)
Finally a Honda packaged 36531-RBB-003 (Nov 2023)

They all fail the same way, with a Honda-Specific error to do with the output signal missing from the O2 sensor, and/or P1157. I have verified several times that each individual wire from the EMS to the 4 pole WBO2 plug is intact.

A fellow on K20a.org said he had seen O2 failures due to ELD malfunction, but that was killing the O2 heater circuit, which is not the failure I see.

Strange... O2 sensors are essentially a battery with the O2 sensor voltage going into the ECU's input which is essentially an analog to digital converter that should not have any ability to damage the O2 sensor.

The other part of a modern O2 sensor is the heater powered by about 12-14.5 VDC when the ECU system is on..

If the "battery" or sensor section of the O2 sensor is failing, there is likely something in the environment or installation of the O2 sensor causing the failure. Or, something completely wonky with the wiring to the the O2 sensor part, like a power connect unintentionally connected to the O2 sensor's output and ECU's O2 sensor input.. check this..

Modern O2 sensors are very reliable and should not simply fail, replacing them will not be the cure, finding the cause of failure is a must.


Bernice

 

[lookforjoe]

Strange... O2 sensors are essentially a battery with the O2 sensor voltage going into the ECU's input which is essentially an analog to digital converter that should not have any ability to damage the O2 sensor.

The other part of a modern O2 sensor is the heater powered by about 12-14.5 VDC when the ECU system is on..

If the "battery" or sensor section of the O2 sensor is failing, there is likely something in the environment or installation of the O2 sensor causing the failure. Or, something completely wonky with the wiring to the the O2 sensor part, like a power connect unintentionally connected to the O2 sensor's output and ECU's O2 sensor input.. check this..

Modern O2 sensors are very reliable and should not simply fail, replacing them will not be the cure, finding the cause of failure is a must.


Bernice

Thank you for the input Bernice. It is indeed perplexing. The Honda EMS is very particular about the input signal from the WBO2, so generic and KO sensors don't work at all (I tried). Unfortunately I cannot just leave it alone with the bd sensor, as I mentioned, the car doesn't run right (way too rich) if it is driven with a bad sensor.

There is definitely NO wiring issues, I already tested each individual wire, specifically because I did have that problem at one time (in that case, repairing the wire resolved the CEL, and no sensor replacement was necessary. Whatever is going on now, is killing the sensor output. As soon as the new sensor is connected, the CEL corrects itself, so the system acknowledges the rectified circuit even before the engine is started.

 

[Rupunzell]

Thank you for the input Bernice. It is indeed perplexing. The Honda EMS is very particular about the input signal from the WBO2, so generic and KO sensors don't work at all (I tried). Unfortunately I cannot just leave it alone with the bd sensor, as I mentioned, the car doesn't run right (way too rich) if it is driven with a bad sensor.

There is definitely NO wiring issues, I already tested each individual wire, specifically because I did have that problem at one time (in that case, repairing the wire resolved the CEL, and no sensor replacement was necessary. Whatever is going on now, is killing the sensor output. As soon as the new sensor is connected, the CEL corrects itself, so the system acknowledges the rectified circuit even before the engine is started.

Put a current meter in series with the O2 sensor output wire to the ECU. there should be only a tinny-tiny amount of current (micro-amps if that) in that circuit and put a voltmeter on the O2 sensor output in parallel with the ECU to monitor the O2 sensor's output.

Heater circuit of the O2 sensor will draw plenty of current, typically in amperes..

Problem cannot be found without some instrumentation..


Bernice

 

[Rupunzell]

specifically because I did have that problem at one time (in that case, repairing the wire resolved the CEL, and no sensor replacement was necessary.

That wiring problem might have damaged the ECU's O2 sensor input, now causing problems with any O2 sensor used.

~Check this.


Bernice

 

[lookforjoe]

That wiring problem might have damaged the ECU's O2 sensor input, now causing problems with any O2 sensor used.

~Check this.


Bernice

I don't think so - the only way I could test that would be to change the ECU, but again, once a new O2 is installed, the system functions as it should (for varied amounts of time) If there were a hard fault with the ECU, then I would expect the new O2 sensor to not change anything. The ECU has to have a modified chip board to run the EMS overlay (KTuner). The other ECU I own that is chipped, has no provision for CEL, so back when I used that ECU, I did not know that the O2 Sensor had failed, except that the readings were way off when the laptop was attached to monitor the system.

 

[lookforjoe]

Put a current meter in series with the O2 sensor output wire to the ECU. there should be only a tinny-tiny amount of current (micro-amps if that) in that circuit and put a voltmeter on the O2 sensor output in parallel with the ECU to monitor the O2 sensor's output.

Heater circuit of the O2 sensor will draw plenty of current, typically in amperes..

Problem cannot be found without some instrumentation..


Bernice

I can make an adaptor harness to bridge the O2 and harness plug, then measure the amps on the signal lead. I can measure / view the sign al voltage in software, so not sure there is anything to gain using an external voltmeter. Heater circuit is not a problem, that is never the failure.

 

[lookforjoe]

O2 wiring diagram. Heater circuit goes through a separate relay. I could always make a new harness for the O2 voltage signal loop A28 & A31

 

[ng_randolph]

O2 wiring diagram. Heater circuit goes through a separate relay. I could always make a new harness for the O2 voltage signal loop A28 & A31


View attachment 79020

What type of wiring is used for the O2 sensor? Did the Honda / Acura harness use shielded wire or some other special wiring for this? Are the wires close to any noise sources (like ignition wiring)?

 

[dcioccarelli]

I can make an adaptor harness to bridge the O2 and harness plug, then measure the amps on the signal lead. I can measure / view the sign al voltage in software, so not sure there is anything to gain using an external voltmeter. Heater circuit is not a problem, that is never the failure.

So no expert in these matters but I wonder whether it is simply the fact that you are running the engine in such a different way to what it was designed for that is causing the car's ECU to detect that the signals that it receives (not at a single point in time but rather over samples taken at various temperatures, etc.) do not match with the model that it is expecting?

I know in my Peugeot when I had the EGR blocked off (temporarily) the temperature sensor on the intake manifold would throw an error saying that it didn't match the correlated value from the air filter sensor (presumably it was expecting a higher temperature due to the exhaust gasses being recirculated). So modern ECUs have very specific ideas about the values that they expect to see and will throw error codes when you fall outside the expected range.

All of that said, the fact that a brand new sensor will immediately fix the issue is strange. Are you also resetting anything (or clearing error codes) at the same time as replacing the o2 sensor?

If a new sensor does indeed fix the issue without anything being reset in the ECU then this could point to the o2 sensors becoming fouled, contaminated or exposed to temperatures outside their limits.

Anyway, best of luck with the troubleshooting!
Dom,

 

[lookforjoe]

What type of wiring is used for the O2 sensor? Did the Honda / Acura harness use shielded wire or some other special wiring for this? Are the wires close to any noise sources (like ignition wiring)?

All of that said, the fact that a brand new sensor will immediately fix the issue is strange. Are you also resetting anything (or clearing error codes) at the same time as replacing the o2 sensor?

If a new sensor does indeed fix the issue without anything being reset in the ECU then this could point to the o2 sensors becoming fouled, contaminated or exposed to temperatures outside their limits.

Anyway, best of luck with the troubleshooting!
Dom,

Thanks for the suggestions.
The harness is not shielded wiring, nor is it in proximity to the ignition circuit, the wiring is actually all OEM layout. I have added additional circuits, but nothing that generates 'noise', nor wrapped with the harness that includes the WBO2 signal and heater circuit.

With the O2 failure, I don't have to reset anything as far as error codes go. The system clears itself as soon as the key is turned on, unlike error codes relating to lean or slow response from the O2, or Heater circuit codes. I always assume the code needs to be cleared, so I connect the OBDLink app, & get "no codes detected". I drove the car yesterday for a few miles and all is normal as far as response & AFR readings go.

Maybe the problem is that it just sits too much. However, I've never had an O2 failure for that reason before. It can't be due to excessive heat as the sensor is pretty far downstream, pre cat, as it would be on the factory RSX setup. I probably have greater distance if anything, with the extra runner length of the RAM headers. Maybe I should put it in the cat, where it would get hotter, however I did have it in that location before I discovered the cause of the reading variations between the system WBO2 & AEM WBO2, and I still had sensor failure.

 

[86X]

I I have told some folks that are way smarter than me on this matter to see if they have any suggestions.
It sounds like you are running a set up like my 2ZZ. I have 2 WBO2. One to the ECU and one to an AEM gage? It looks like one is on the bottom and one on the top. Have you tried changing which one is on top to see if that makes a difference. I am just curious if the bottom one may be collecting moisture. Here is my WBO2s it's hard to tell but they are both just after my headers in the decat pipe, they are Bosch 4.9.

Those are some beautiful headers you made.