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Discussion Starter · #1 ·
After I installed my ZDX(J37) throttle body, the car will idle fine when you turn it on, but when you drive it for like a minute or two and then let it idle, the rpms will fluctuate from about 1.5k rpm to 1.2k rpm. After about 5-10 seconds of doing that, it will start idling normally.

Any idea what could be causing this?

I checked to make sure everything was installed correctly and I didn't leave anything disconnected.

-Dennis @PRL motorsports said to check for vacuum leaks.
-Vit said to adjust the set screw for a 1400 rpm idle warm with the tb unplugged.
-Honda leader tech where I work said to have the car retuned because it's an issue with the current tune since I installed the TB after I was done tuning.
 

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Discussion Starter · #2 ·
Heres a video of the problem. I'm not touching the gas pedal at all, this is the car doing it by itself.

 

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Did you do a datalog to see if the throttle plate is adjusting or increasing/decreasing, I'd say vac leak also.Also a datalog would show the AFM fluctuating?


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It may only be a coincidence, but that issue was present in my Si at one point as well. It went away after updating the FlashPro Manager. I don't think Hondata actually tests their work on an actual vehicle. They probably run some simulation and if it checks out, they launch the update.

EDIT: Windshield Wipers to the rescue at 0:24! :3tens:
 

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Were you able to perform an idle learn? The problem is most likely due to a larger air flow volume than the ECU is calculating.

At a given throttle opening a larger TB will allow more air in than stock which will raise the idle and cause the ECU to try and compensate.
 
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Discussion Starter · #6 ·
Were you able to perform an idle learn? The problem is most likely due to a larger air flow volume than the ECU is calculating.

At a given throttle opening a larger TB will allow more air in than stock which will raise the idle and cause the ECU to try and compensate.
I just texted you
 

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I installed my ZDX TB with my RBC and did not perform an idle learn. I would think a vacuum leak would be constant and would not go away.
 

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It may only be a coincidence, but that issue was present in my Si at one point as well. It went away after updating the FlashPro Manager. I don't think Hondata actually tests their work on an actual vehicle. They probably run some simulation and if it checks out, they launch the update.

EDIT: Windshield Wipers to the rescue at 0:24! :3tens:
Love the windshield wiper quote....lol
 

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Discussion Starter · #9 ·
I installed my ZDX TB with my RBC and did not perform an idle learn. I would think a vacuum leak would be constant and would not go away.
I had a Honda tech leader check the car yesterday and he said no vacuum leaks going on.
 

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Discussion Starter · #10 ·
It may only be a coincidence, but that issue was present in my Si at one point as well. It went away after updating the FlashPro Manager. I don't think Hondata actually tests their work on an actual vehicle. They probably run some simulation and if it checks out, they launch the update.

EDIT: Windshield Wipers to the rescue at 0:24! :3tens:
LOL I think I found my solution
 

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Have you tried the set screw like Vit had mentioned? I think he knows a thing or two about these cars ;)
 

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Discussion Starter · #12 ·
Have you tried the set screw like Vit had mentioned? I think he knows a thing or two about these cars ;)
I'm going to try that tomorrow. It's going to be a PITA though because the screw is upside down in a practically unreachable part, so I have take the TB off and mess with the screw until I get it right.
 

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Discussion Starter · #13 ·
I found the solution to the problem. Turns out Vit was right(of course). For anyone in the future who runs into this issue, here's what you gotta do:

-You'll need an Allen wrench. I'm not sure the exact size.

-Turn the car on

-Unplug the throttle body(at this point the revs will get higher, don't get scared this is normal)

-Locate the small set screw right under the hoses

-Turn the screw counterclockwise with the Allen wrench until there's no more fluctuation and the rev decreases to 1400 rpm

-Turn the car off

-Reconnect the throttle body sensor/plug

-Turn the car back on

-You'll have a few engine lights on. You can get rid of them with Flashpro.

Enjoy!
 

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Your screw is hard to reach? I have the zdx tb and it's right on top. Mine goes up to 2k on random cold starts sometimes and vit told me to do the same thing. Mess with the screw. I just haven't done it yet.
 

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Discussion Starter · #16 ·
Your screw is hard to reach? I have the zdx tb and it's right on top. Mine goes up to 2k on random cold starts sometimes and vit told me to do the same thing. Mess with the screw. I just haven't done it yet.
I wasn't looking at the right screw the first time around lol

It's very simple. Just follow the post above and you'll be all set. After that, it's mainly tb learning procedure. Within 30 mins or so of driving the car, the idle will completely go back to normal.
 

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looks like that guy Vit knows wtf he's talking about eh?
 

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Discussion Starter · #19 ·
looks like that guy Vit knows wtf he's talking about eh?
Eh... I can still teach him a few stuff here and there lol

Thanks for helping me out yesterday bro. I really appreciate it!
 

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I wasn't looking at the right screw the first time around lol

It's very simple. Just follow the post above and you'll be all set. After that, it's mainly tb learning procedure. Within 30 mins or so of driving the car, the idle will completely go back to normal.
What do you means guys when you are talking about "idle learn" I'll purchase zdx tb soon, dont want any problem... After zdx installed , idle learn is it needed or not..? Because my plan is to get all my parts ( cai,zdx tb,dp,cat back, flash pro) install it by myself on a saturday and get it tune monday morning! So a guy from honda tell you that if you had your zdx tb before the tune, it will run properly at idle without messing with the allen key screw ? Or have to do a " idle learn " im still wondering if its gonna do a noticable difference with the bigger tb ?


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