Hey guys,

So I have been running the DIYPNP MS2 on my '00 NB for a while now and things are running well.
I have also got the turbo conversion all finished and a reasonable tune in place (running low boost 9/10 psi).

I thought it was time to finish off all the small stuff and get the car a little more refined but now have run into an issue with the IAC PWM valve. I see a lot of people have trouble tuning closed loop PWM but I am having a problem before even getting this far, its like my valve isn't responding to the ECU.

So I set the ECU to PWM warmup only as some have suggested, but the valve doesn't seem to be doing anything.
I thought the valve might be dead so with the engine running I disconnected the wire to the valve and put 12V across it, you could hear a click as the valve opened and the revs shoot upto 4-5000rpm.
Put a multimeter across one of the pins that usually go into the valve and there is a constant 12V as you would expect.
Put the multimeter across the two pins and get 7.5/8.5V, about what I would expect to see with PWM (unfortunately I don't have a spectrometer to check this 100%).

I found there is a Idle Valve Test so ran this but no changes I make in this do anything at all.


As a test I enabled the FIDLE in the output settings and the ECU throws out 12V to the valve and revs jump up to 4-5000rpm.


So now I am a bit confused.
I know the ECU is actually connected to the valve but I cant control it correctly. Has anyone come across something like this?
I'm pretty sure the valve was working fine on the original ECU about 6 months ago.

Is there anyone out there that might be able to shed some light on this?
Ideas?

Cheers,
Dale

 

you mean it sends a constant ground to the idle valve fully opening it...

the valve runs using a PWM ground. There's constant 12v and the MS rapidly grounds it.


with those fidle output settings, I see no reason it would do anything at idle... you dont have the output trigger until you are over 6K. Plus, there'd be a conflict error unless you disabled idle control completely.

 

Yep that's what I mean, just typed it a bit odd. I can see the ECU pulls the pin to ground but doesn't seem to be pulsing it (well the valve doesn't react like it is pulsing).

I just used those screenshots to reference the pages where I was trying to test the valve. In the Valve test page I was using figures between 0 and 100. In the FIDLE I actually used coolant as the trigger. (trigger worked great but it nailed the valve fully open as you would expect with that test)

Sorry about that confusion.

 

I'm also tuning an '00 NB, though not yet turbo'd. I'm using an MSPNP2 and I'm tuning around a set of Deatsch 700cc injectors. Idle is fine, using either PWM warmup or closed loop. I had to tweak several idle control parameters to get there though.

Disregarding the fidle output port setup, how have you set up your idle control? Are you using PWM Warmup? Please post your .msq file so we can have a look.

 

PWM Warmup is for lazy losers who can't take 2 minutes to set up the idle valve settings and then the next 5-10 minutes to correctly tune the CL PID.

unsure why youre getting no reaction in the idle valve test mode, are you sure you're idle settings page is setup for FIDLE?

 

I will eventually run PWM closed loop but for now I'll take anything.

At the moment if I try and use PWM warm-up and play around with the settings (and I mean play around with different settings for over an hour) there is 0 response.
I see on the dashboard gauge the Idle PWM % will change to what ever I set it to for that scenario but there is no response from the valve, I have had it up to 60% with no change.

Another strange thing is when I used FIDLE to 100% open the valve even when I turned this back off it stayed open and I had to shutdown the engine and start again. On restart the valve will be closed again.

What are the chances the valve is faulty? It certainly opens and shuts fine but maybe it cant respond to the PWM?

 

Mine behaved the same way until I reworked the settings. I was pretty frustrated for a while. Please post your .msq file and we might be able to help.

 

Ok I'll get mine up ASAP (they are on my 'tuning' laptop so cant get it up right now).
What settings did you have to re-work? maybe I can take a look as soon as I get back out to the car (and if I cant get anything to work get my msq up).

Appreciate the help guys, cheers.

 

My IAC was completely unresponsive with the base tune. The car would fast idle only for the 10 seconds crank-to-run taper duration, then drop to an unreliable slow idle.

The big issue issue for me was the PWM idle valve frequency multiplier. Mine was set to 15 in the base tune the 99-00, which is the max choice in the list box. After a lot of digging in this forum, I found that the multiplier needed to be 16. I had to edit the ini file to get 16, which works a treat.

PWM cranking duty and PWM duty table needed considerable tweaking as well.

Hope this helps!

 

OK will have a look tomorrow morning and will post back the results with the .msq

I saw the multiplier of 15 and some people were using 16 but the software forced it as a max of 15, I didn't think this would have much of an impact but obviously did for you.

 

Ok so I wasn't 100% sure what I had changed while trying to get this working so decided I would go back to the base map from DIYAutoTune.
http://www.diyautotune.com/diypnp/ap...00-18bp-mt.zip
I am also running firmware ms2extra_3.2.1

As I didn't have the Req_Fuel 100% right on my first tune I thought this would be a good time to get that closer to what I needed.
The base map had the Req_Fuel at 13 and originally I reduced this down to 7.5 with the new RX8 injectors which I think was a bit off. I am now using 8.5 and it seems much closer to what I want.

Unfortunately the Idle valve issue still remains and is exactly the same as before. All is back to the default idle settings and have tried both PWM warmup and PWM closed loop but still no luck. I also tried changing the valve freq multiplier to 15 with no change. (is this the same that happened with you, but then you went to 16 and got a response?)

 

Yes. That is correct. I was not able to get any response whatsoever from the IAC valve, other than during the crank-to-run taper at start-up. Once I edited the ini file to set the freq multiplier to 16, all worked fine, and has ever since.

 

ok I might as well give it a go, nothing else is working!

Do you remember what .ini file you had to modify and how you modified it?

 

Just looked back over my config and I realized I'd edited my .msq file and not my .ini file. Sorry for any confusion. Open your .msq file with a text editor and search for the following line: <constant digits="0" name="pwmidle_freq">16.0</constant>

You can see where I changed the value to 16.

Hope this helps!

 

Ok that makes more sense, I was looking everywhere for a .ini file without any luck. I have modified the .msq file and will give it a go.
Cheers for the help, I'll let you know how it goes.

 

One last thing to change; Valve mode should be "Inverted, 100 % = off"

Give it a try and let us know if it works. Good luck!

 

it shouldn't be inverted.

 

Does the inverted/not inverted choice vary among the various MS/MSPNP/TunerStudio/Megatune implementations? or... Did the '99 and '00 models ship with more than one type of IAC valve?

The base tune that came with my MSPNP2 was set to inverted. I experimented with the setting when my IAC initially wasn't working and found it went wide open and stayed there when I set it to normal - like 4k RPM. Inverted, it works as should.

While searching through this forum for answers to my idle problem, I found enough seemingly contradictory information to make it difficult for me to know what was right for my situation. Much of the info came from earlier versions of TunerStudio and Megatune. It was necessary for me to experiment in order to find what actually worked. I'll be curious to see what wydra reports back.

I must say, I'm still very much a newb to the MS and TunerStudio, and I still have a lot of questions that need answering before I'll feel really comfortable with the system, but I'll put those in another thread.

What settings are other '99 and '00 owners using?

 

Ok so none of this has made any difference to my valve at all.
Freq multipier of 9, 15, 16 and even tried 18.
Inverted and Normal.
I have also bumped the Duty Cycle up to 60%.

The tunerstudio dash is showing the duty cycle changing as it should so I have come to the conclusion it is 1 of two things. Either the ECU is not outputting what I need it to or the valve is faulty.

I have purchased a DigitalMultiMeter that has a Freq/Duty Cycle function so I am going to see what the output of the ECU is.

 

Does the engine fast-idle for 6 seconds, just as it starts, before dropping? That's what your setup showed in post#11 for crank-to-run time. If it does, then you know your IAC valve operates.

Have you disabled idle control in order to experiment with FIDLE? I see the crank-to-run setting greyed out in post#15. If so, be sure MS is set to operate the IAC normally.