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Discussion Starter · #21 · (Edited)
I’m confused. Didn’t you search for a factory condition ECU specifically to get kpro installed? You can’t do a k24 swap without Kpro, keep this in mind as I remember you saying you wanted to do so in a year.

Also, did you relocate your ground strap to the head?
@mfarmakas17

Yes.

But my MAIN priority is to get these two (2) issues fixed first. And if it means losing the KPRO ( for now ), by switching to a NON-KPRO ECU, I am fine with that ( for now ) .

[ Please see my post just above ]

Look forward to your reply.

..
 

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Discussion Starter · #22 ·
I have an extra 2003 PND ECU, matching immobilizer and matching key for my 2003 Base RSX.

I want to rule out KPRO as a suspect.

1) - Being that I did an Auto to Manual Swap, will a NON-KPRO ECU, matching immobilizer and matching key ( from a salvage ) allow me to start the car ?

----------------

2) - Would it be as easy JUST PHYSICALLY installing the immobilizer and plugging in the ECU ? Or is it more complicated than that ?
 

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Discussion Starter · #23 ·
UPDATE :


Thanks to @Lotus_Elise , I discovered that the Upstream Sensor for an Automatic ECU is different from one for a Manual ECU. And being that the Primary O2 sensor was never swapped/changed from an Auto O2 Sensor to a Manual O2 Sensor.

So THIS might resolve my issues with the RPM Dips ( when A/C is on ) and the P0141 CEL.

So apparently I still have the Automatic version of the Primary O2 since it was never switched out for a Manual Priamry O2 when the "Auto-toTrans" swap was done.

This became more clear to me when I went to . . .

https://www.densoautoparts.com/

And saw three (3) different Upstream / Primary sensors

Denso 234-9006
Position: Upstream / Transmission Control Type: Automatic

Denso 234-9005
Position: Upstream / Engine Designation: K20A2

Denso 234-9004
Position: Upstream / Engine Designation: K20A3 / Transmission Control Type: Manual

================

Tomorrow, I am going to install a new Primary O2 Sensor ( the upstream ) . It is a Denso 234-9004 for a manual.

1) -
Once the O2 sensor is replaced, ( if all goes well ) SHOULD the CEL light turn off immediately, or does the car have to be driven awhile ?

And SHOULD this help with the RPM dips ( rough idle ) when A/C is on ?

================

Alternative Plan ( if all else fails ) . . .

IF I want to rule out KPRO as a suspect . . .

I have an extra 2003 PND ECU, matching immobilizer and matching key for my 2003 Base RSX.


1) - Being that I did an Auto to Manual Swap, will a NON-KPRO ECU, with a matching immobilizer and a matching key ( from a salvage ) allow me to start the car ?


2) - Would it be as easy as JUST PHYSICALLY installing the immobilizer and plugging in the ECU ? Or is it more complicated than that ?
 

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The auto ecu should still be able to start the car. The primary sensor doesn’t matter unless it’s for the wrong generation. I run a type s sensor on mine, but this is for the a/f sensor. You said you have P0141, and that’s for the secondary sensor. What happens if you disable it in Kpro? You never mentioned whether you relocated your ground either. Hondata recommends this because the factory location isn’t that good.
 

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It might be worth familiarizing yourself with the K-Manager software in order to potentially solve your issue. If switching to the manual o2 sensor doesn't fix it, I recently had an issue with my idle that I was able to fix by switching a setting in K Manager.

You might also want to disable the secondary o2 in the software as well, that'll keep the code from coming up.

What just happened to me was I cleaned my throttle body and IACV to try and clean up the weird idle issues I was having. After putting it all back together, I had a surging insufficient idle. I doubled back on everything I did and made sure I had no leaks or anything. In K Manager, there is a setting under the IDLE tab that has a slider to control the idle value duty cycle adjustment. I can't remember precisely, but on the pop up prompt, it says to slide it to the left if you are having idle fluctuations and slide it to the right if you are experiencing idle dip. Sliding it to the left and uploading that change cleared my idle issue immediately.
 

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UPDATE :


Thanks to @Lotus_Elise , I discovered that the Upstream Sensor for an Automatic ECU is different from one for a Manual ECU. And being that the Primary O2 sensor was never swapped/changed from an Auto O2 Sensor to a Manual O2 Sensor.

So THIS might resolve my issues with the RPM Dips ( when A/C is on ) and the P0141 CEL.

So apparently I still have the Automatic version of the Primary O2 since it was never switched out for a Manual Priamry O2 when the "Auto-toTrans" swap was done.

This became more clear to me when I went to . . .

https://www.densoautoparts.com/

And saw three (3) different Upstream / Primary sensors

Denso 234-9006
Position: Upstream / Transmission Control Type: Automatic

Denso 234-9005
Position: Upstream / Engine Designation: K20A2

Denso 234-9004
Position: Upstream / Engine Designation: K20A3 / Transmission Control Type: Manual

================

Tomorrow, I am going to install a new Primary O2 Sensor ( the upstream ) . It is a Denso 234-9004 for a manual.

1) -
Once the O2 sensor is replaced, ( if all goes well ) SHOULD the CEL light turn off immediately, or does the car have to be driven awhile ?

And SHOULD this help with the RPM dips ( rough idle ) when A/C is on ?

================

Alternative Plan ( if all else fails ) . . .

IF I want to rule out KPRO as a suspect . . .

I have an extra 2003 PND ECU, matching immobilizer and matching key for my 2003 Base RSX.


1) - Being that I did an Auto to Manual Swap, will a NON-KPRO ECU, with a matching immobilizer and a matching key ( from a salvage ) allow me to start the car ?


2) - Would it be as easy as JUST PHYSICALLY installing the immobilizer and plugging in the ECU ? Or is it more complicated than that ?
The salvage/new key won’t work in your existing key cylinder I believe. What I did to pass smog with a stock ecu and matching immobilizer/key without changing the cylinder was to install the new stock ECU, unplug my immobilizer (but leave in place), zip tie the new immobilizer close enough that the connections reach, plug it in, remove the chip from the new key and tape the chip to the new immobilizer (you might have to experiment with exact placement), and voila, car will start and run with just the new immobilizer, keys and ecu, but with your existing key in the cylinder to turn the car over
 

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Discussion Starter · #27 · (Edited)
The auto ecu should still be able to start the car. The primary sensor doesn’t matter unless it’s for the wrong generation. I run a type s sensor on mine, but this is for the a/f sensor. You said you have P0141, and that’s for the secondary sensor. What happens if you disable it in Kpro? You never mentioned whether you relocated your ground either. Hondata recommends this because the factory location isn’t that good.
Thanks @mfarmakas17 .

Will try changing out the Auto A/F sensor for the Manual A/F sensor.

1) - Once the O2 sensor is replaced, ( if all goes well ) SHOULD the CEL light turn off immediately, or does the car have to be driven awhile ?

And SHOULD this help with the RPM dips ( rough idle ) when A/C is on ?

=============

1) - If I DIS-able the secondary O2 sensor in KPRO, would I pass emissions ?

2) - Would this correct my air fuel ratio when the A/C fans kick on ?

=============

IF that does not help anything, then the next thing to do is to have the shop look at the wiring and ground.

1) - What exactly are they supposed to ground ?

2) - And where should they ground it ?
 

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Thanks @mfarmakas17 .

Will try changing out the Auto A/F sensor for the Manual A/F sensor.

1) - Once the O2 sensor is replaced, ( if all goes well ) SHOULD the CEL light turn off immediately, or does the car have to be driven awhile ?

And SHOULD this help with the RPM dips ( rough idle ) when A/C is on ?

=============

1) - If I DIS-able the secondary O2 sensor in KPRO, would I pass emissions ?

2) - Would this correct my air fuel ratio when the A/C fans kick on ?

=============

IF that does not help anything, then the next thing to do is to have the shop look at the wiring and ground.

1) - What exactly are they supposed to ground ?

2) - And where should they ground it ?
What I’m saying is that replacing your auto primary sensor with the manual one does not matter unless you have the sensor for the wrong generation. Your a/f ratio should be stoic (14.7:1) at all times unless you’re in open loop (wide open throttle or WOT). There will be more load on the engine with the a/c, but it shouldn’t throw off your a/f ratio. Only tuning can correct it, so no the sensor won’t make a difference. I didn’t take emissions inspection into consideration, so disabling the secondary will not help here. Read the below link, you can relocate the ground without going to the shop.

 

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Discussion Starter · #29 ·
What I’m saying is that replacing your auto primary sensor with the manual one does not matter unless you have the sensor for the wrong generation. Your a/f ratio should be stoic (14.7:1) at all times unless you’re in open loop (wide open throttle or WOT). There will be more load on the engine with the a/c, but it shouldn’t throw off your a/f ratio. Only tuning can correct it, so no the sensor won’t make a difference. I didn’t take emissions inspection into consideration, so disabling the secondary will not help here. Read the below link, you can relocate the ground without going to the shop.

@mfarmakas17

Not to sound too dumb, but when you say . . .

. . . replacing your auto primary sensor with the manual one does not matter unless you have the sensor for the wrong generation.


Q1) - What do you mean by " wrong generation " ?


Q2) - Can you please send a link so that I know / confirm what the correct part is for my generation ?

I have a 2003 RSX M/T ( Base ) 5-speed .

To the best of my knowledge it should be . . .
Denso 234-9004 ( https://www.densoautoparts.com/ )
Position: Upstream / Engine Designation: K20A3 / Transmission Control Type: Manual

Q3) - Once the O2 sensor is replaced, ( if all goes well ) SHOULD the CEL light turn off immediately, or does the car have to be driven awhile ?

==========

ISSUE 1 -

My main concern at this point is to get rid of this CEL code .
My understanding is that this P0141 CEL is either an O2 sensor part, or a wiring / ground issue, or both.

Grounding for KPRO :

Correct ?

---------------------

ISSUE 2 -

My understanding is that the RPM dips when A/C fan is on is a tuning calibration issue.

Correct ?
 

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Discussion Starter · #30 ·
@mfarmakas17

Trying not to confuse myself when I speak to the Shop and then to the Tuner .

Can you please offer some step-by-step direction on what I need to do or tackle in order to resolve both of my issues ?

Step-by-step direction for The Shop .

And a Step-by-step direction for The Tuner .

Very grateful.

Thanks in advance.
 

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@mfarmakas17

Not to sound too dumb, but when you say . . .





Q1) - What do you mean by " wrong generation " ?


Q2) - Can you please send a link so that I know / confirm what the correct part is for my generation ?

I have a 2003 RSX M/T ( Base ) 5-speed .

To the best of my knowledge it should be . . .
Denso 234-9004 ( https://www.densoautoparts.com/ )
Position: Upstream / Engine Designation: K20A3 / Transmission Control Type: Manual

Q3) - Once the O2 sensor is replaced, ( if all goes well ) SHOULD the CEL light turn off immediately, or does the car have to be driven awhile ?

==========

ISSUE 1 -

My main concern at this point is to get rid of this CEL code .
My understanding is that this P0141 CEL is either an O2 sensor part, or a wiring / ground issue, or both.

Grounding for KPRO :

Correct ?

---------------------

ISSUE 2 -

My understanding is that the RPM dips when A/C fan is on is a tuning calibration issue.

Correct ?
When the RSX was revised, the 05-06 model was considered a second generation. You have the right primary sensor, so why do you think that it's malfunctioning? Your CEL is P0141, correct? That's referencing your secondary sensor, not the primary. That's what needs to be looked at. I'm not sure if the CEL will clear on it's own because I've always done that myself.

The sensor could be bad, or your harness could have been damaged last time it was at the shop. Maybe the mechanic was a little careless and tugged on it. They should be able to test it with a multimeter if you do go back to the shop, but a loose harness is typically easy to spot.

As for tuning, I know that it helped with my idle issues after I installed bolt ons. This was due to short term fuel trim. If you didn't have this problem with your previous ECU though, the tuner isn't really the guy to go to. His job is to tune, not diagnose and repair.


You had said that your a/f ratio is incorrect when your a/c is on. Your a/f ratio should be 14.7:1 at all times with minor variations except in open loop function. If your car is running in open loop at all times, it's because you selected that option on Kpro, or your a/f sensor is malfunctioning. Once again, your CEL is for the secondary sensor so I don't think that your a/f ratio is a problem here.
 

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Discussion Starter · #32 · (Edited)
When the RSX was revised, the 05-06 model was considered a second generation. You have the right primary sensor, so why do you think that it's malfunctioning? Your CEL is P0141, correct? That's referencing your secondary sensor, not the primary. That's what needs to be looked at. I'm not sure if the CEL will clear on it's own because I've always done that myself.

The sensor could be bad, or your harness could have been damaged last time it was at the shop. Maybe the mechanic was a little careless and tugged on it. They should be able to test it with a multimeter if you do go back to the shop, but a loose harness is typically easy to spot.

As for tuning, I know that it helped with my idle issues after I installed bolt ons. This was due to short term fuel trim. If you didn't have this problem with your previous ECU though, the tuner isn't really the guy to go to. His job is to tune, not diagnose and repair.


You had said that your a/f ratio is incorrect when your a/c is on. Your a/f ratio should be 14.7:1 at all times with minor variations except in open loop function. If your car is running in open loop at all times, it's because you selected that option on Kpro, or your a/f sensor is malfunctioning. Once again, your CEL is for the secondary sensor so I don't think that your a/f ratio is a problem here.
Thank you.

So if my understanding is correct . . .

1) - The two issues I am dealing with are NOT likely originating from KPRO ( unless it somehow has a constant "open loop" enabled ) .

But is more likely from a ground and/or loose wire with the secondary O2 sensor.

NOTE: The CEL comes on immediately when the car turns on, and even when the code is cleared.

======

2) - I can see if a Tuner can calibrate KPRO to deal with the A/C electric draw to get rid of the RPM dips.

======

Is my understanding on both of these correct ?
 

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Thank you.

So if my understanding is correct . . .

1) - The two issues I am dealing with are NOT likely originating from KPRO ( unless it somehow has a constant "open loop" enabled ) .

But is more likely from a ground and/or loose wire with the secondary O2 sensor.

NOTE: The CEL comes on immediately when the car turns on, and even when the code is cleared.

======

2) - I can see if a Tuner can calibrate KPRO to deal with the A/C electric draw to get rid of the RPM dips.

======

Is my understanding on both of these correct ?
Honestly dude, I think the rpm issue is just in your head lol. I can’t even tell you what I think it might the without actually seeing it myself. Address the CEL, and contact an etuner. Personally, i wouldn’t bother unless I was going for an actual tune, but maybe they won’t charge you.
 

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Discussion Starter · #34 · (Edited)
Honestly dude, I think the rpm issue is just in your head lol. I can’t even tell you what I think it might the without actually seeing it myself. Address the CEL, and contact an etuner. Personally, i wouldn’t bother unless I was going for an actual tune, but maybe they won’t charge you.
@mfarmakas17

I just uploaded this video for you to see .

The RPM needle continuously bobbing up and down when the A/C fans kick on is real.

In the video you can clearly hear the A/C clicking on and off. Which causes the car to stall on the road.

This phenomena and the P0141 code occurred after the Auto-to-Manual Swap .

NOTE: We replaced the Secondary O2 with an NTK (24409). The CEL comes on immediately when the car turns on, and immediately after the code is cleared. Maybe the ECU cannot detect the Secondary O2 due to a wire or ground so it does not know how to regulate the Air/Fuel ratio. Or Maybe there is a "default" setting in KPRO that is causing this. NO Tune was done at the shop. Just used KPRO to DIS-able the immobilizer.


=========

Does this phenomena look familiar ?

...
 

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Alright, that’s pretty bad…
Once again though, this should have absolutely no effect on your a/f ratio and I’m still confused as to why you think that is the problem. Your primary sensor is what the ECU uses to adjust fuel trims, the secondary is there to monitor the cat and that is the only thing it does.

I’d relocate that ground strap first, look around the engine bay for anything that may have been left unplugged, and check your fuses while you’re at it. I haven’t been under the hood in a while, but I’m pretty sure there’s a fuse or relay for the secondary sensor.
 

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Discussion Starter · #36 ·
Alright, that’s pretty bad…
Once again though, this should have absolutely no effect on your a/f ratio and I’m still confused as to why you think that is the problem. Your primary sensor is what the ECU uses to adjust fuel trims, the secondary is there to monitor the cat and that is the only thing it does.

I’d relocate that ground strap first, look around the engine bay for anything that may have been left unplugged, and check your fuses while you’re at it. I haven’t been under the hood in a while, but I’m pretty sure there’s a fuse or relay for the secondary sensor.
Thank you.

It usually takes about 8 to 10 minutes of the car running idle for it to start acting up.

========

So your opinion is that this is NOT a KPRO thing, but most likely physical or a fuse.

And that calibrating KPRO settings might not do anything.

=======

Is my understanding correct ?

...
 

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Thank you.

It usually takes about 8 to 10 minutes of the car running idle for it to start acting up.

========

So your opinion is that this is NOT a KPRO thing, but most likely physical or a fuse.

And that calibrating KPRO settings might not do anything.

=======

Is my understanding correct ?

...
Correct. It’s honestly hard to say because you had the swap done at the same time, but I’ve never seen this issue mentioned before with Kpro. It would suck if you got rid of it just because there was something that got overlooked during your swap.
 
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