IAC tuning. Am I crazy? (Solved!)

[JSC]

Loaded 2.36 last night, hooked up the scope this morning on a cold start, all the steps I looked at were perfect!

Thanks Al, Great job.

Scott

[grippo]

So I have a question..

Is there any possibility that this programming glitch could have resulted in any other problems with the ECU?

The reason I'm asking is because I had been having a problem with my fuel only MSII suddenly "hickup" for a split second. Especially around 3000rpm. Looking at the datalogs it was hard to tell what the problem was... it sorta looked like tach spikes/dropout on the datalog, but it was hard to actually nail down and often did not show up as a tach spike but you could see a dutycycle spike (not accell enrich) the ECU didn't appear to be resetting although I did see the odd reset after a particularly bad event. Anyways, it appears as tho this new version of the firmware has fixed this problem as well? Or at least dramatically reduced the frequency?

The only changes since my last test drive has been the firmware and I'll need to take the car for a couple more test drives to know for sure, but it sure seems better.

You guys think it was just a coincidence?

I really think your hiccup is a totally different issue. This code bug can only do one thing - inhibit the proper advance and retard of the stepper motor. This stepper movement should be all over after the car is warmed up. The bug in the code can't make the stepper reactivate - if anything it would make such a problem less severe because it woudl have slowed down the motor in the event that some other bug was sending inappropriate step commands.

[JSC]

BottleFed70;
I had a situation a couple weeks ago where things just started acting weird, couldn't figure out why so I reloaded the code and it started acting right again. Maybe all you needed was a reload.

Scott

[krisr]

It might be worth while getting a few more to street test then releasing this code as the next stable version.

[Joethemechanic]

Hey Guys,
I am also quite happy to report that 2.36 appears to be working like a charm. THANK YOU AL!!!!

no scope paterns yet but it does warm up nicely, comes al the way down and the IAC appears to do everything I tell it to.

one thing I did notice while testing it, I set my cranking value ( engine fully warmed up ) to 0, to see if it would do a full sweep on start-up.
it never came all the way down, seemed to stop shy about 10-15 stepps ( 100-150 rpm ) I increased My start value to 210 ( was 200 ) and increased the step time to 6ms.
It always acted the same, seemed to stop just shy of fully closing.
This, however, is just a minor glitch I noticed, possibly my start value needs to be more, I don't care as it seems to be working fine in the real world!!

[bluetrepidation]

NICE. I'll test tomorrow!

A.J.

[Joethemechanic]

Hey Al, could you possibly whip up a 2.6xx with the bug fix??

I am eager to play with the X-tau.

Thanks again, Joe

[Ballistic]

Hmmm, I've now got a warmup idle that is 100-150 RPM lower than the idle speed on a restart. I increased step size from 2.5ms to 4.0 but it didn't seem to make a difference.

[bluetrepidation]

My IAC now works as advertised.

+100,000

MEGA KUDOS!

Thanks all! This was making me THINK I was crazy as the title states. Now I know I'm not! Well at least when it comes to my Megasquirt..... but that is another story.

Oh and thanks Scott for the scope traces. Good work.

A.J.

[TurboGt]

I have just found this thread and have the same problems as everyone else.

I just finished loading the new code and am going to test it.
Do I need to add a jumper of any of the resisors, if so which ones? v3 board.

Thanks for all the work that went into this

Marq