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93 hatch (money pit)
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Discussion Starter · #1 ·
Alright I've been trying to hunt this down for too long now and I've ran out of ideas. Here's a video with the jist of whats happening.

https://www.youtube.com/watch?v=88FTrby13gM

The video is an example of one of it's calmer starts. Basically on start up it will hunt for a few seconds before going into a normal idle. And after a rev or after pushing in the clutch the car will bounce a bit till returning to normal. Occasionally idle will stay high stay 1500rpm while coasting after popping into neutral until it slowly drops.

It's a D15b7 with y8 head / intake manifold / tb ran via p28 ecu.

Here's a list of everything I've tried so far:
-Every sensor other than coolant sending unit is brand new.
-Checked for vacuum leaks via propane torch and brake clean method no dice
-Removed pcv (brand new oem) hose from manifold and plugged its port on the intake manifold no change
-Removed brake booster hose from manifold and plugged its port on manifold.
-Checked grounds at each sensor for any weird values
-Checked that the proper ecu wire is going to each sensor via multimeter continuity setting
-Set ignition timing to 12 degrees
-Double checked mechanical timing. Other than 1/2 tooth timing error due to the y8 head it's mint.
-With iacv unplugged it idles at 700rpm steadily. (Idle screw fully in drops it to 500 rpm but caused occasional stalling when popping clutch in)
-Removed throttle body for cleaning and re adjusted the plate stopper followed by re calibrating tps to .45v at closed 4.5v at WOT.
-Ensured throttle cable wasn't over tight
-Bled coolant of any air
-Tried another ecu. No difference
-Multiple idle re learn processes has been attempted after each change

I'm probably forgetting stuff since I've tried so many things at this point. I've read and followed some of the bigger guide posts:
http://www.d-series.org/forums/diy-forum/270946-how-fix-honda-idle.html
https://www.ericthecarguy.com/kunen.../41476-solving-honda-idle-issues-hunting-idle

I have my IAT sensor reading from the stock air box due to the y8 manifold not having the port. I understand that the IAT can change igniton timing based on temps to help prevent knock but I've also read about people leaving them hanging by the fire wall with no issue.
 

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The problem is likely the Frankenstein of parts but does it have a FITV? If so remove or adjust it. There is a YouTube video on how to adjust it.
 

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Brokedick Millionaire
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unplugged IAC idle at 700 (too high) means you have a vacuum leak somewhere.

Random pic of old parts and I found out why the cammed D15Beast7 with ported intake and TB never idled right.

 

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Sloppy Jalopy
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like hondadna said mish mash of parts .

had similar happen when using y8 intake and tb with p06 ecu ,switched to b7 intake and tb and problem fucked off or most likely was coincidence :)

but in your video its not all that bad ...
 

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93 hatch (money pit)
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Discussion Starter · #7 ·
The problem is likely the Frankenstein of parts but does it have a FITV? If so remove or adjust it. There is a YouTube video on how to adjust it.
Sadly no FITV.

unplugged IAC idle at 700 (too high) means you have a vacuum leak somewhere.

Random pic of old parts and I found out why the cammed D15Beast7 with ported intake and TB never idled right.

I know your not suppose to mess with the idle screw but I stupidly touched it about a year ago when I was first chasing this issue. When it's turned all the way in it can idle at 500 rpm with the IACV unplugged but occasionally between shifts it would stall when it was fully tightened. I purposely left it a little high because it idled best at that rpm.

I do know the throttle plate doesn't have any issues like that because during the stopper adjustment I checked to see how much light could be seen through the edges. I did notice some light bleed through the top and bottom but it was very minuscule.

like hondadna said mish mash of parts .

had similar happen when using y8 intake and tb with p06 ecu ,switched to b7 intake and tb and problem fucked off or most likely was coincidence :)

but in your video its not all that bad ...
I may be able to hunt down a b7 throttle body to test with. Personally I'd rather not swap the whole manifold if it came to it I'd probably just live with the idle issue.
 

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My two cents: a propane torch and brake clean is not an intelligent or safe way to check for vacuum leaks IMHO.:)
 

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93 hatch (money pit)
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Discussion Starter · #9 ·
My two cents: a propane torch and brake clean is not an intelligent or safe way to check for vacuum leaks IMHO.:)
I could have worded that better. Both tests were conducted months apart.

And I have a good update to drop almost all of this idle issue seems to have been due to a shoddy oreillys map sensor. With the new one in place the ghost revs are nearly 100% gone. I need to dial in the idle now but it should be good finally.
 
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