Attached is both my MSQ and a log file. I should also clarify, this is another install I'm doing for a friend, so it is a complete standalone install, not parallel like my car in my sig. This is from a 95 M-Edition, 450cc DSM injectors (with resistors), and a GT2560.

Ok, looks like this is going to need a bit of tweaking. The settings can be a bit confusing, and the fact that the "dc"s in the settings are really pulse widths doesn't help. The way the control works is that the "Frequency" value is inverted to become the maximum pulse width. Any DC value greater than the Frequency number is actually full open. So on your MSQ you can set the DC values to anywhere between 0 and 26, but 26 or higher correspond to fully open.

Lower your min and closed more. Mine are at like 6 or 7.

I tried this and my car started idling very strange and very high kind of like when I unplugged the idle valve all together.

I think i am just having a really hard time understanding how the idle settings and the idle valve work. Should I just close up the idle screw all together and start playing with the settings in megatune to find what works?

Also, i've noticed that I can change the settings to lower numbers without restarting the squirt, but if I try and increase the values I have to restart to get the changes to take. Is this normal?

I'm not heartbroken that my idle doesn't work 100%, it gets me by just fine the way it is but i'd like to know what i'm not doing right.

After some experimenting, I still have the same issues unfortunately. With the idle valve disconnected, I can watch the IdleDC gauge change values as if Megasquirt thought it was actually controlling the idle.

Appearing to act normal when disconnected from the IAC valve, I plug it in. Immediately, the idle shoots up to about 2400RPM and the IdleDC gauge just sits at the closed value. I attempted to completely close the idle screw, but it changed the idle minimally. I used my Harbor Freight multimeter on the connector and it read what appeared to be battery voltage (13.xx V) and a frequency of .26 KHz, appearing to fluctuate somewhat randomly from .19 - .26 KHz (but I doubt the accuracy of the multimeter).

I also hear a slight whistling sound coming from the IAC valve when disconnected (but engine idling). I doubt any vacuum leaks as nothing has changed since I bought the car and it idled fine with MS2extra.

So unless something has been fried on the idle valve itself, I'm somewhat dumbfounded as to what is going on.

Please help!!

Very interesting that you got the idle dc to change by unplugging the valve itself. I have no idea what that means nor do I know where to go from here. I want to try that myself though.

I actually observed a wackier idle with my idle valve unplugged vs it being plugged in. When I punched in a 6 for closed and min DC it acted exactly as it did when I unplugged the valve itself.

Anyone else have ideas what's going on? Matt, your input would be highly appreciated.

Yes, and Joe's input as well.

I'm about to take a shot in the dark and try replacing my TIP120. I dont know how to test it for functionality and its cheap so i'll give this a shot tomorrow and see what happens.

I think my biggest problem is my great lack of understanding about how this SHOULD work. Without knowing how the whole thing is suppose to work I cannot troubleshoot a goddamn thing.

Played with this more today (haven't replaced that TIP yet like I said I would). Here are my observations from today:

First, i tightened my idle screw all the way so it wasn't playing any role in this anymore.

I noticed on the DC gauge that i'm getting a change from cranking DC (35) to my closed dc when starting my car. This is the only time I ever see this gauge move.

I set my min DC to 7 and played with my closed DC a bit. Got it to idle real nice at 850-900 with no accessories turned on. Turned on the headlights, the idle droops slightly, then turn on the fans and it droops slightly more but really not too much. Revved it a few times and it seemed pretty stable. Something is still not 100% consistant, not sure why though. Sometimes the idle will settle a little too high, sometimes a little too low. If I blip the throttle a bit i can get it to try again and get it to settle properly.

I'm still getting droop if I push in the clutch from high rpms. If I play with the throttle and ease it back down to idle it doesn't seem to be too big of an issue.

Correct me if i'm wrong, but here is what i'm understanding about this PWM valve and MS. When I turn the lights on or some other thing that droops my idle, the DC gauge should increase a little bit to compensate until it settles, correct? In other words, as things change that affect my idle, i should definitely see the idle dc gauge doing something. Is there a difference in MT between the "Idle DC and the "IdleDC" (note the space)? I have both to choose from, both seem to do the same thing.

So overall, with a min of 7dc and a closed of 10 i seem to be seeing the best idle thus far. if I lower the closed to 9, the idle is too high. Higher than 10 it idles too low.

In other news, i finally turned on TPS accel enrichment today. OMG it drives like butter now.

Interesting stuff. I'm still hoping Matt from DIY sees this and can add any input. I'm still suffering from the same issues as I stated earlier.

Yes. You should see the IdleDC gauge moving around when the car is idling, and when you are not idling, the gauge should display the "closed" value.

IdleDC and Idle DC are the same thing. If you open the msns-extra.ini file you see that they both point to the same variable.

Forgive me if this is redundant, but a quick tutorial.

The "closed" value is the duty cycle that the MS feeds to the IAC valve in order to close it fully. When you're not idling (ie: you are driving) the IAC valve should be closed, so the MS sends it the "closed" value. When you drop down into the realm of idle, the MS goes to the "Min" value and then starts seeking the target, and you should be seeing movement on the gauge during this time.

Now, you're seeing the "closed" value all the time, and furthermore, altering the closed value is altering your idle. This means that the MS is never even attempting to go into idle mode- for some reason it doesn't think you're trying to idle.

This is not a hardware problem. At least, not in the idle circuit itself. Although 7 is an astoundingly low idle DC value. Mine runs best in the low to mid 20s.


I would like to try an experiment. Change your idle screen as follows:
http://img18.picoodle.com/img/img18/...em_f2723a2.gif

This allows us to directly input static idleDC values for warm and cold idle, rather than letting the MS seek a target RPM. See if this gets the IdleDC gauge moving to a value other than closed.

Thanks for the review Joe, I think I understand much better now. As you say, it really doesn't seem like the MS wants to get into idle mode.

K, sitting in the car right now.

Warmup only with those settings is different. It started at 26dc, then down to 25, then 24 continually to 22 where it sits now. (the engine was 140* at startup).

Droop is way worse with warmup only, turn the lights and heater on and it is down to ~500rpms.

This is an interesting datapoint.

From everything you've said, it seems that the hardware is working, and the MS is capable of controlling it. However it is refusing to go into closed-loop idle mode when you are in the correct range. Somethin' screwy.

A question- have you tried just re-flashing the MS firmware with a fresh, known-good .S19 file? It's almost like something is just fubar in the operating code.

Yes I have reflashed recently. .s19 is what I create with easytherm, right? I redid that with my last flash as well.

I've had a few beers tonight so my critical thinking skills are not up to par. Perhaps i'll try reburning tomorrow. The idle valve works with the stock ecu just fine so i am reasonably sure that is not the issue. Are you sure its nothing hardware related?

Major Breakthrough...

TPS Threshold ADC was at 10, needed to be higher. This is why the MS was never even trying to control idle.

Playing with it right now but may have some questions shortly.

Question 1:

Idle DC gauge seems high. Was over 200% now at 130, looks to be dropping as I warm up. Is this normal

Now it either just sits at the min or closed value. If I turn my lights/hvac on it still droops, DC changes but it doesn't quite pick up all the way back to normal. Also, it is still idling high in the 1100 rpm range. Changing the values for slow and fast idle has no effect.

Ha!

I was looking at the log and saying "no, this TPS is going to 0 when he's off-throttle" without it clicking that the log only contains scaled TPS, not raw TPS ADC, which is what the idle screen uses. I guess the mechanical calibration of your TPS is somewhat askew. :)

Lets' have a new set of MSQ and Log, so we can see what it's doing now. I'm a bit confused when you say that the idle gauge is showing 130-200%. The gauge is only scaled from 0-100%, and mine never goes higher than the mid 30s. Can we get a copy of your msns-extra.ini file as well? It's in C:\Program Files\MegaSquirt\MegaTune2.25\mtCfg\

Yes, the counting down is mighty strange. I noticed also that after I change any setting to do with idle the gauge goes up to 250% and quickly counts down from there and sits at either the min or closed value.

Here is an .MSQ and my .ini for now. Will grab a log later.

Edit: Cannot attach .ini

Yesterday I tried playing with my idle some more. It never goes below 1100 and usually just sits at 1300 these days. Idle screw is all the way closed.

I pulled the IAC plug while it was idling, no change. Plugged it back in, no change. Unplugged it again and revved the engine a bit, no change. So it looks like my IAC doesnt work anymore. Could I have broken this messing around with MS settings? Seems like it must be stuck open for it to idle with the idle screw all the way closed. I'm reasonably concerned that someday its going to decide to stick closed when I really dont want it to.