Idle air control valve discontinued

[Jinks]

Well, looks like Honda discontinued yet another part for our cars. I was able to find one on Amayama though for 183 bucks. After having my full motor build and having Shad analyze my tune he stills thinks this valve is the reason I go lean and almost stall sometimes on throttle lift.
‘My question to some of you Prime masters is what page in the service manual is this located? I know there is coolant running through this part and I was told to pinch the lines to eliminate as much air in the system as possible. Anyone have anything else to add? Thanks.

 

[Mac Attack]

The EACV is shown on page 11-3. It does not have coolant running through it. The fast idle valve does, however. Both are shown on page 11-83. You'll see why the fast idle valve has coolant running through it.

However, as a lot of us recommended in your other thread, why not remove/clean/replace your old EACV?

Also, the tune I modified still has room for adjustment to improve that issue. The idea is you make small incremental adjustments and use continuous feedback to make it better. I'm just amazed after the lack of tuning knowledge DA (and SOS) has demonstrated, you're taking their word the tune is good and it's a hardware issue? You really need to take it to a professional tuner in your FL area.

 

[Jinks]

The EACV is shown on page 11-3. It does not have coolant running through it. The fast idle valve does, however. Both are shown on page 11-83. You'll see why the fast idle valve has coolant running through it.

However, as a lot of us recommended in your other thread, why not remove/clean/replace your old EACV?

Also, the tune I modified still has room for adjustment to improve that issue. The idea is you make small incremental adjustments and use continuous feedback to make it better. I'm just amazed after the lack of tuning knowledge DA (and SOS) has demonstrated, you're taking their word the tune is good and it's a hardware issue? You really need to take it to a professional tuner in your FL area.

Thanks Dave, eventually I will take it to kings performance and yes, I am amazed at the lack of support as well. It’s been a total turn off for me. I’ll look into the EAVC valve as well. I did some of the recommended changes as you instructed me but the problem still presented itself. It doesn’t do it all the time which confuses me on how the tune would affect it? But I’m all ears so thanks for the input.

 

[Jinks]

I ordered both the Idle control valve and the fast idle valve. I’ll give that a try first. Once I can actually take a day off work, I’ll go get a retune.

 

[Mac Attack]

I did some of the recommended changes as you instructed me but the problem still presented itself. It doesn’t do it all the time which confuses me on how the tune would affect it? But I’m all ears so thanks for the input.

Did you make all of the changes to your tune as I recommended in this post?
http://www.nsxprime.com/forum/showthread.php/205400-Still-having-idle-issues-help-please/page2?p=1965739&viewfull=1#post1965739

If so and there are still intermittent problems, go to your Idle parameter tab. On the RPM Offset vs TPS graph for throttle percentages 4% and higher, change the 250 RPM to 400 RPM. Right click on the dots and select "Select Value" to change them.

I'll admit, it may be a sticking EACV causing your issues. But, I prefer to do the simple things first, and we've already established your original idle tune was completely out of whack. Since we've worked on the idle tune, you say it's gotten a lot better, so I would adjust it a bit more and hope that does the trick....

 

[Mac Attack]

...Shad analyze my tune he stills thinks this valve is the reason I go lean and almost stall sometimes on throttle lift.

Oh, BTW, you want the engine to go lean when you lift the throttle. That's the way it should be.

 

[Jinks]

The afrs go to 17 when the engine almost stalls. That’s probably normal as the ecu is cutting fuel I dunno. Yeah Dave, it is so strange. We did the idle wizard and it worked fine for a little bit then the problem came back. I do not disagree the cold idle is way high on the tune but once the engine warms up it’s buttery smooth. It’s just the damn thing wants to try and stall sometimes but not always once I pull out of gear and coast off of throttle. It’s freaking annoying and I wish the car was still in California...
I did several adjustments recommended in my thread but nothing changed. So I uploaded the original tune back to the ecu. I already ordered the parts for the TB so let’s start there and see where I am at. Eventually, I will have a retune. But I need to make sure the car will get me there first.

 

[Mac Attack]

I did several adjustments recommended in my thread but nothing changed.

What were those? Some were niceties, and others were required. Your RPM Offset vs. TPS graph is one of the important ones - Did you change that?

 

[Larry Bastanza]

Just wanted to mention I have had this issue with many NSX's. On a stock engine I have been able to resolve this easily by clearing the idle passage (remove idle setting screw and blow out the passage). I know you do not have a stock engine, and many other things come into play, especailly the fact that Shad is working on it, but just wanted to mention it, since I have seen it so often.

HTH,
LarryB

 

[Mac Attack]

Just wanted to mention I have had this issue with many NSX's. On a stock engine I have been able to resolve this easily by clearing the idle passage (remove idle setting screw and blow out the passage). I know you do not have a stock engine, and many other things come into play, especailly the fact that Shad is working on it, but just wanted to mention it, since I have seen it so often.

HTH,
LarryB

Good point and something else that should be checked.

When I do an engine rebuild I clean everything. For example, it took an ultrasonic bath and a few cans of brake cleaner to clean my OEM NSX oil cooler during a rebuild (on a perfectly good engine), and then I didn't even re-use it. Just re-oiled it and tucked it away in my stockpile.

You would think the TB would have been cleaned out, but maybe not....

 

[RYU]

Just wanted to mention I have had this issue with many NSX's. On a stock engine I have been able to resolve this easily by clearing the idle passage (remove idle setting screw and blow out the passage). I know you do not have a stock engine, and many other things come into play, especailly the fact that Shad is working on it, but just wanted to mention it, since I have seen it so often.

HTH,
LarryB

Larry could you kindly show a picture of where this passage is located? I didn't even know the NSX had a idle control screw this entire time...

 

[Larry Bastanza]

I do not have pics handy, but in the 1991 service manual page 11-84, in the 1997-2005 manual page 11-151........

 

[jwmelvin]

I didn't even know the NSX had a idle control screw this entire time...

I’m going to pretend you didn’t say that.

 

[RYU]

I’m going to pretend you didn’t say that.

someone took over my computer again!

 

[Jinks]

Larry could you kindly show a picture of where this passage is located? I didn't even know the NSX had a idle control screw this entire time...

It’s the screw right above the felxible air intake tube. You use this flathead screw to adjust idle.
Also, thanks Larry B. Everything was thoroughly cleaned during engine build but I high pressure warshed everything in the intake manifold with coolant and oil when she blew. So it is possible these idle sensors are f@cked up but I also do not disagree with Mac here. I am just going off of what my engine builder recommends. It sucks being in between everything.

 

[Jinks]

What were those? Some were niceties, and others were required. Your RPM Offset vs. TPS graph is one of the important ones - Did you change that?

I’m pretty sure I did the ones you recommended. I’ll have to check my notes. But pretty sure I did the RPM VS TPS. It didn’t fix it. Gimme a few days I’ll recheck it. Thanks for your help.

 

[Kaz-kzukNA1]

Don't know your aftermarket software spec for the idle control but with OEM, this is the port/screw used for the base idle control.

non-DBW: small round brass colour, at the right shoulder of the TH butterfly.

DBW here.

You could clean and replace the filter/gasket at the EACV and Fast Idle control valve (only used on non-DBW model) but I would do the easy bits first.


Kaz

 

[Mac Attack]

I’m going to pretend you didn’t say that.

I let it slide because I think he's overseas on vacation....

I’m pretty sure I did the ones you recommended. I’ll have to check my notes. But pretty sure I did the RPM VS TPS. It didn’t fix it. Gimme a few days I’ll recheck it. Thanks for your help.

It's good you're keeping a log!

Changing the tune would not have made any difference until you corrected the error locking out the entire idle control due to your TPS not being sync'd.

Once you and Shad got that straightened out, is that when you tried the parameters I suggested? If that RPM vs TPS change did not help, then it should be adjusted a bit more. The idea is to make small incremental steps on one parameter at a time and log the differences it makes.

I mean, your values were set to zero and even AEM says this parameter IS VERY IMPORTANT to prevent stalling when lifting off the throttle. I didn't capitalize it - AEM does in their documentation. It fixed my stalling issue and, barring any hardware problems you have, is probably the biggest contributor to your issue.

 

[jwmelvin]

The Kaz mic drop hits again. I love that. [MENTION=25737]Kaz-kzukNA1[/MENTION] you, sir, are a gentleman and a scholar.

 

[Mac Attack]

Great pictures Kaz - Thank you!

 

[Jinks]

I let it slide because I think he's overseas on vacation....




It's good you're keeping a log!

Changing the tune would not have made any difference until you corrected the error locking out the entire idle control due to your TPS not being sync'd.

Once you and Shad got that straightened out, is that when you tried the parameters I suggested? If that RPM vs TPS change did not help, then it should be adjusted a bit more. The idea is to make small incremental steps on one parameter at a time and log the differences it makes.

I mean, your values were set to zero and even AEM says this parameter IS VERY IMPORTANT to prevent stalling when lifting off the throttle. I didn't capitalize it - AEM does in their documentation. It fixed my stalling issue and, barring any hardware problems you have, is probably the biggest contributor to your issue.

Yes we got the tps all set and ran it for a 1/2 hour. I made the adjustments you recommended a couple weeks after that.
I’ll try and send you my new file if you do not mind having a look see.

 

[furinax]

Is it required to remove the part in order to clean IACV? I have been stalling with the A/C on and did a throttle body cleaning. All I did was shoot the cleaner into the hole in front of the throttle plate but it still didn't fix my stalling. I was wondering if there was another easily accessible spot one could clean.

 

[Jinks]

Is it required to remove the part in order to clean IACV? I have been stalling with the A/C on and did a throttle body cleaning. All I did was shoot the cleaner into the hole in front of the throttle plate but it still didn't fix my stalling. I was wondering if there was another easily accessible spot one could clean.

You have to remove the two coolant lines and the two 10mm bolts. You only lose about a 1/4 cup of coolant or less. The filter on mine was pretty caked up but it didn’t fix my idle issue which I believe is directly related to tuning.

 

[lazyboyz69]

I didn't remove the coolant lines. I removed the two 10mm bolt, I sprayed some carb cleaner, brushed with toothbrush, wipe it down. Seems to help not stalling with the A/C on.

 

[Jinks]

I didn't remove the coolant lines. I removed the two 10mm bolt, I sprayed some carb cleaner, brushed with toothbrush, wipe it down. Seems to help not stalling with the A/C on.

I’m sure you could keep it connected. But since I have a carbing strut bar and it takes forever to get to these parts, I pulled it all the way out for a thorough cleaning. I also, did not want carb cleaner running through my coolant system at high temps. So I pulled it all the way off. But I suppose either method will suffice. Just personal preference.