Acura RSX, ILX and Honda EP3 Forum banner
1 - 20 of 37 Posts

·
Registered
Joined
·
269 Posts
Discussion Starter · #1 · (Edited)
All electrical stuff is working great after the trans swap .

But, I noticed that when the car is parked, and the A/C is on that the RPM's were dipping pretty low .

BEFORE THE SWAP, I had seen a dip whenever the A/C was on and when the radiator fans would cut on intermediately. But nothing all that bad.

But AFTER the swap THIS RPM dip was going up, down, up, down, up, down in a faster succession ( like every 2 seconds ) when the car is parked, and the A/C is on.

This gets much better when parked with the A/C off. It might dip like every 3 minutes or so.

Any ideas ?

=======

NOTE : Before the swap, I had an existing P1259 and a P0420 code.

I have not scanned the OBD yet to see if there is anything else, but plan to.

=======

Is this a "new" M/T ECU swap thing ?

A VTEC solenoid thing ?

An A/C crank pulley thing ?

Or something else ?
 

·
Registered
Joined
·
269 Posts
Discussion Starter · #2 · (Edited)
Mine has done the dip ever since I had omar from street scene do my tune with k pro. If you aint running factory tune it will do it more than likely no matter who you have tune it.
@Integraman

1) - So is this an alternator or a KPRO thing ?

So far my stuff is stock except for a Short Ram and an HKS exhaust.

NO Tune.

2) - Where exactly do I go in KPRO and which generic Base tune would resolve this ?

OR . . .

3) - Since I have NO tune, would a Denso Alternator fix this ?

======

Side question . . .

4) - What is the difference between a Denso Alternator and one from Advance Auto Parts ?

========

5) - Will this RPM Dip ruin or mess up something ?

. .
 

·
Registered
Joined
·
269 Posts
Discussion Starter · #4 · (Edited)
4) - What is the difference between a Denso Alternator and one from Advance Auto Parts ?

The Denso will get installed once. The one from Advance will get replaced at least once per year.
Would this help fix “ The Dip “ in RPM’s while parked with the A/C on ?

In other words, is the Denso alternator more powerful than the one that came from the factory ?

If not, it would seem that I am replacing “apples-for-apples”.

Let me know.
 

·
Boosted K20A3
Joined
·
118 Posts
Which flywheel did you have installed? Do you know if the shop adjusted the IAC or idle settings at all in K-Pro?

I didn't have the super frequent dips you're describing after my auto to manual swap (+ turbo), but I used a lightweight flywheel. The lightweight flywheel made idle MUCH more difficult in my setup, so I finally went to a less lightened flywheel and the dips and rpm drops have minimized significantly now. I am not saying this is your issue, but this was my experience with the auto to manual. I did my swap myself, though, so I don't have as much potentially lost in translation as you do since a shop did the work.
 

·
Registered
Joined
·
269 Posts
Discussion Starter · #6 ·
Which flywheel did you have installed? Do you know if the shop adjusted the IAC or idle settings at all in K-Pro?

I didn't have the super frequent dips you're describing after my auto to manual swap (+ turbo), but I used a lightweight flywheel. The lightweight flywheel made idle MUCH more difficult in my setup, so I finally went to a less lightened flywheel and the dips and rpm drops have minimized significantly now. I am not saying this is your issue, but this was my experience with the auto to manual. I did my swap myself, though, so I don't have as much potentially lost in translation as you do since a shop did the work.
Thanks for the reply.

NOTE: This only happens when parked and A/C is on.

Is this the same with you ?

=========

1) - I have an Exedy OEM style flywheel

2) - As far as I know, they only DIS-abled the immobilizer using KPRO

=======

Look forward to your reply.
 

·
Registered
Joined
·
269 Posts
Discussion Starter · #7 ·
3) - Does the upstream or downstream Oxygen sensor need to be changed when doing a Trans Swap ?

4) - Does the Idle Air Control Valve need to be changed when doing a Trans Swap ?

Would either of these cause the RPM's to dip when parked with the A/C on ?
 

·
Boosted K20A3
Joined
·
118 Posts
3) - Does the upstream or downstream Oxygen sensor need to be changed when doing a Trans Swap ?

4) - Does the Idle Air Control Valve need to be changed when doing a Trans Swap ?

Would either of these cause the RPM's to dip when parked with the A/C on ?

Sorry, I forgot to check here for a couple days.

Since you have a stock weight flywheel, I don’t suspect the issues I’m describing are relevant to you. A/C is a load on the system that a lightweight flywheel could affect even at idle/parked (this is what I observed), but the heavier OE flywheel compensates for these normal dips while the IAC adjusts accordingly. There is also an IAC setting in k-pro to make the IAC adjustments more pronounced, but again, this isn’t sounding like your issue now.

Your oxygen sensors are not affected by the manual swap. They should be in the exact same place.

Your IAC is the same between manual and auto. The type s one is functionally the same, but has a different coolant fitting.

What version of kpro did the shop install (side note - very strange to have kpro just for an immobilizer)? If it’s v4, you could download the Hondata app and check your codes there. I wish they still offered the old free app in addition to the two new paid ones, though.

This may sound silly, but have you done a full once over in the engine bay to make sure all connectors are connect? I’ve had a car returned to me from a shop before with multiple things disconnected, yet everything still had the appearance of working.
 

·
Registered
Joined
·
269 Posts
Discussion Starter · #9 · (Edited)
Sorry, I forgot to check here for a couple days.

Since you have a stock weight flywheel, I don’t suspect the issues I’m describing are relevant to you. A/C is a load on the system that a lightweight flywheel could affect even at idle/parked (this is what I observed), but the heavier OE flywheel compensates for these normal dips while the IAC adjusts accordingly. There is also an IAC setting in k-pro to make the IAC adjustments more pronounced, but again, this isn’t sounding like your issue now.

Your oxygen sensors are not affected by the manual swap. They should be in the exact same place.

Your IAC is the same between manual and auto. The type s one is functionally the same, but has a different coolant fitting.

What version of kpro did the shop install (side note - very strange to have kpro just for an immobilizer)? If it’s v4, you could download the Hondata app and check your codes there. I wish they still offered the old free app in addition to the two new paid ones, though.

This may sound silly, but have you done a full once over in the engine bay to make sure all connectors are connect? I’ve had a car returned to me from a shop before with multiple things disconnected, yet everything still had the appearance of working.
Thanks for the indepth reply.

@claymiester

My check engine light has a P0141 Code.

I have 2003 Base .

So I am replacing the O2 sensor with a Denso 234-4122 Downstream Oxygen Sensor.

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


QUESTION 1 :

When the RPM's dip ( with the A/C "ON" ) the car gets a bad rough idle. It will even stall if the car is slowly trying to pull into my driveway because the RPM's dip severely ( with the A/C "ON" ) .

Do you think replacing the O2 Sensor will help resolve my issue ?

QUESTION 2 :


Earlier you said, " Your oxygen sensors are not affected by the manual swap" . But what about the fact that the ECU was swapped and is no longer an Auto is now an M/T, and that the ECU helps regulate the fuel ratio based on what the O2 tells it ? Does the M/T ECU have to be configured somehow ?

QUESTION 3 :

According to . . .

https://honda-tech.com/forums/honda...stion-98-accord-6th-gen-1930023/#post26976347

It said," the difference between the Manual and the Auto ECU is that the auto ecu has the TCU built in "

"
What is a Throttle Control Unit ? "

The quote above was in reference to a '98 Honda Accord.
So I am NOT certain if the same is true or not for an RSX ( See hondata ) .

But IF a Manual RSX's ECU does not have a built-in TCU due to the trans swap, is this somehow affecting my idle ( with the A/C "ON" )?

What should I do ?

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

NOTE :

I am using KPRO V4.

NO Tune or base maps being used at this time. Just the immobilizer was DE-activated.

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

VIDEO SOURCES concerning the IACV and O2 Sensors :

" DC5 stalling IACV valve and O2 oxygen sensor . RSX stalling. "

https://www.youtube.com/watch?v=pyoAyFUduaQ ( this refers to a Type-S )


" Syptoms of a Bad Oxygen Sensor "

https://www.youtube.com/watch?v=XDBs_hoSRPM


" Here's the TWO SENSORS YOU NEED TO REPLACE FOR BETTER IDLE !! "

https://www.youtube.com/watch?v=vQC4MNuz_JA
 

·
Registered
Joined
·
269 Posts
Discussion Starter · #13 · (Edited)
Sounds like your idle need to be raised up a bit maybe 150-200 rims with screw near throttle blade stopper and idle air control valve needs to be cleaned.
I do not recommend adjusting the throttle screw. The manual even specifically states this. Idle is controlled through the ECU using your IACV
Well when you disable iacv and delete it you have to along with adjust a few things in k pro
Ok folks. Thanks for the replies.

Here's what I got going on . . .

The P0141 code calls for a Downstream O2 sensor. Turns out the Denso package said " 234-4122 ", but what was actually in the box was an UPSTREAM sensor.

I went ahead and put it in the catalytic. Amazingly, the RPM Dip issue stopped ( even though it was NOT the correct type of sensor ) .

BUT . . .the engine light was still there with the P0141 code.

So, I went to Advance and got an NTK " 24409 " Downstream sensor ( the EXACT SAME sensor as what comes from the factory ).

I took out the Denso and put in the NTK.

The RPM Dip issue came back even though I used the EXACT SAME sensor ( NTK ) as what comes from the factory.

When the A/C fans kick-on the RPM needle bobs back and forth, causing the car to shake and almost stall. And the engine light still shows a P0141 code.

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

QUESTIONS :

Q1) -
Do I need to drive the car around for the O2 sensor to get calibrated ? If yes, how far ? How many drive cycles ?
Or should the CEL have gone away immediately ?

Q2) - Is my catalytic converter bad ? I do not see any codes for bad cat.

Q3) - NOTE: The shop that did my swap did NOT do any tune.
They just attached the KPRO'ed ECU and DIS -abled the immobilizer. That's it .

Q4) - Is it possible that there is a PRE-set on the KPRO V4 that was already enabled by Hondata before the new ECU was added to the car ?

NOTE: The shop that did my swap did NOT do any tune.

Q5) - Is a Dealership ( stealership ) my best / only option ?

And would it matter to them that I have a NON-tuned KPRO'ed ECU ?

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

NOTE : Before the swap, I had an existing P1259 and a P0420 code.

AFTER the swap, those codes disappeared, and a P0141 code is what I now get.

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


Help.
 

·
Boosted K20A3
Joined
·
118 Posts
Very interesting that the issue disappeared with the wrong sensor. Had this been with the upstream sensor (used for measuring AFR), I would have suspected the car simply went into open loop, which would indicate a closed loop related issue. However, since it was the downstream sensor (used for detecting the cat effectiveness), I am surprised you observed a difference. Of note, both your previous P0420 code and the new P0141 code indicate an issue observed at the downstream sensor - either that the cat is no longer effective or that there is a sensor or wiring related issue.

Do you observe a change in idle by simply disconnecting the downstream sensor?

To directly answer some of your questions, though:
1. I've typically seen a 3 start/stop cycle for resetting O2 sensor related codes, but not reliably.
2. As stated above, both of the codes could indicate a bad cat, but could also be a bad sensor or wiring to the sensor (of note - I believe you said your wiring was changed for the manual swap, since this is in the engine harness IIRC).
3 and 4. You need to know which calibration was used. If they slapped a used ECU with K-Pro on it, there is no telling what calibration/"tune" is on it to begin with. There should be nothing wrong with using the factory calibration in K-Pro, which is under the "RSX (Base) - PND" vehicle type, and is titled "k20a3-base-factory.kal". The immobilizer disable is one of the settings in the calibration file, so I imagine the shop used that calibration file, but it's worth confirming.
5. The dealership will likely be completely ignorant of K-Pro and is unlikely to be a good option. Your best option is the shop that did the work.
 

·
Registered
Joined
·
269 Posts
Discussion Starter · #15 ·
Very interesting that the issue disappeared with the wrong sensor. Had this been with the upstream sensor (used for measuring AFR), I would have suspected the car simply went into open loop, which would indicate a closed loop related issue. However, since it was the downstream sensor (used for detecting the cat effectiveness), I am surprised you observed a difference. Of note, both your previous P0420 code and the new P0141 code indicate an issue observed at the downstream sensor - either that the cat is no longer effective or that there is a sensor or wiring related issue.

Do you observe a change in idle by simply disconnecting the downstream sensor?

To directly answer some of your questions, though:
1. I've typically seen a 3 start/stop cycle for resetting O2 sensor related codes, but not reliably.
2. As stated above, both of the codes could indicate a bad cat, but could also be a bad sensor or wiring to the sensor (of note - I believe you said your wiring was changed for the manual swap, since this is in the engine harness IIRC).
3 and 4. You need to know which calibration was used. If they slapped a used ECU with K-Pro on it, there is no telling what calibration/"tune" is on it to begin with. There should be nothing wrong with using the factory calibration in K-Pro, which is under the "RSX (Base) - PND" vehicle type, and is titled "k20a3-base-factory.kal". The immobilizer disable is one of the settings in the calibration file, so I imagine the shop used that calibration file, but it's worth confirming.
5. The dealership will likely be completely ignorant of K-Pro and is unlikely to be a good option. Your best option is the shop that did the work.
Thanks for your reply .

What if I were to go to purchase a "Matching combo" package :
  • Matching immobilizer
  • Matching ECU ( for a manual )
  • Matching Keys

And just switch out these three things in the car, would that resolve my issue concerning the P0141 and the bobbing of the RPM's when the car's A/C fans kick in ?

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

NOTE : Having KPRO is not a priority at this time.

I am just wanting the car to function normally.

...
 

·
Boosted K20A3
Joined
·
118 Posts
Thanks for your reply .

What if I were to go to purchase a "Matching combo" package :
  • Matching immobilizer
  • Matching ECU ( for a manual )
  • Matching Keys

And just switch out these three things in the car, would that resolve my issue concerning the P0141 and the bobbing of the RPM's when the car's A/C fans kick in ?

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

NOTE : Having KPRO is not a priority at this time.

I am just wanting the car to function normally.

...


The above link from Hondata (alternatively - google search "hondata k-pro immobilizer") explains what's needed to make your existing immobilizer and key match your ECU. This does require a dealership (I couldn't find any alternatives), and they typically charge just over $100 for it (total ripoff for 15 minutes of work, but it's their proprietary software).

I really don't think the re-key will fix any of your issues, but it will make the blinking green light go away (and make your ECU require the chip in your key, not just any key cut physically the same).
 

·
Registered
Joined
·
269 Posts
Discussion Starter · #17 ·

The above link from Hondata (alternatively - google search "hondata k-pro immobilizer") explains what's needed to make your existing immobilizer and key match your ECU. This does require a dealership (I couldn't find any alternatives), and they typically charge just over $100 for it (total ripoff for 15 minutes of work, but it's their proprietary software).

I really don't think the re-key will fix any of your issues, but it will make the blinking green light go away (and make your ECU require the chip in your key, not just any key cut physically the same).
Thanks for the reply .

BUT . . .

The reason for getting a "Matching combo" package :

  • Matching immobilizer
  • Matching ECU ( for a manual ) with NO KPRO
  • Matching Keys
Is to just get rid of the ECU that has the KPRO on it.

I hope by doing this that it allow whatever is in the KPRO to no longer affect how the car is rough idling when the A/C fans are on. And to get rid of the P0141 CEL.

====

Does my theoritic solution sound correct ?
 

·
Registered
Joined
·
56 Posts
The key and immobilizer issue has no bearing on the idle drop i can assure you as on my car I took care of that issue thinking the same as you and it did not fix the ac fan idle drop issue. When I had my car tuned I told tuner about me disabling the iacv because when I was supercharged I did not want coolant getting anywhere near the throttle body by any means and he adjusted a ton of stuff to compensate for it down at idle and ever since I put a lightened racing flywheel in it my issue has been like yours and I have gotten real good at giving it gas right before it stalls out to keep it running so it dont cut off and create more wear and tear on my starter. I had my factory original alternator that came with the car rebuild by this old guy who has a huge shop full of alternators and starters and he put performance armatures in it and recoiled it and it helped alot but still does it so to elevate the issue right before I know I am coming to a stop I turn ac off. Real men don't need it anyways. The factory style flywheel you had put in I can guarantee you that if you were to weight it next to the one honda puts in it from the factory it would be lighter. If I was you I would put the wrong sensor in it that made the issue go away and drive at least 30 minutes with the car then if it doesn't go away the engine code then just disable emissions checking on both o2 sensors from k pro. Just a thought.
 

·
Super Moderator
Joined
·
2,040 Posts
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?
 

·
Registered
Joined
·
269 Posts
Discussion Starter · #20 · (Edited)
The key and immobilizer issue has no bearing on the idle drop i can assure you as on my car I took care of that issue thinking the same as you and it did not fix the ac fan idle drop issue. When I had my car tuned I told tuner about me disabling the iacv because when I was supercharged I did not want coolant getting anywhere near the throttle body by any means and he adjusted a ton of stuff to compensate for it down at idle and ever since I put a lightened racing flywheel in it my issue has been like yours and I have gotten real good at giving it gas right before it stalls out to keep it running so it dont cut off and create more wear and tear on my starter. I had my factory original alternator that came with the car rebuild by this old guy who has a huge shop full of alternators and starters and he put performance armatures in it and recoiled it and it helped alot but still does it so to elevate the issue right before I know I am coming to a stop I turn ac off. Real men don't need it anyways. The factory style flywheel you had put in I can guarantee you that if you were to weight it next to the one honda puts in it from the factory it would be lighter. If I was you I would put the wrong sensor in it that made the issue go away and drive at least 30 minutes with the car then if it doesn't go away the engine code then just disable emissions checking on both o2 sensors from k pro. Just a thought.
Thanks for the in-depth reply.

I asked around and a Tuner Guy asked me if the CEL for the P0141 comes on right away . " Yes " it does.

So he broke it down that I may have TWO issues rather than one.

FIRST ISSUE :

Since the CEL comes on immediately after turning the car on, he believes CEL is an electrical or wire issue from the swap where the O2 sensor might not be communicating at all with the ECU .

So he said I should address the O2 Sensor first to get rid of the CEL ( P0141 ).

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

SECOND ISSUE :

I was told that the SECONDARY O2 sensor would have nothing to do with " controlling " whether the fuel goes rich or lean; making the RPM's continuously bob up and down when the A/C fans kick on.

Can anyone confirm that thought ?

---------

His theory is that the RPM needle continuously bobs up and down when the A/C fans kick on because the ECU is not telling the engine to compensate for the heavy electrical load that the A/C fans create.

I was told that this is likely an electrical or wire issue that MIGHT be fixed by doing some electrical RE-calibrations via the KPRO so that the ECU can compensate for the heavy draw that the A/C fans are causing when they kick on.

Can anyone confirm that thought ?


..
 
1 - 20 of 37 Posts
Top