Megasquirt FAQ, writeup (Updated 30/10/09)

[MWP]

^^^^ awesome.
Im sure ill be asking lots of questions soon

[MWP]

So i just ordered:
1 x EBC Electronic Boost Control Solenoid Kit
1 x MegaSquirt Wiring Bundle - 12' Long
1 x MegaSquirt 3X Wiring Bundle - 12' long
1 x JimStim v1.5 MegaSquirt Stimulator w/ Wheel Simulator - Unassembled
2 x Metal DB37 Cover with Hardware & Gaskets
1 x MegaSquirt-III MS3X Expansion Card
1 x MegaSquirt-III w/PCB V3.0 - UnAssembled Kit with black case

... for my 5S-GTE build (+98 Camry block, Caldina head)

[MWP]

Hah...

Subject: Megasquirt FAQ, writeup (Updated 30/10/09)

So i just ordered:
1 x EBC Electronic Boost Control Solenoid Kit
1 x MegaSquirt Wiring Bundle - 12' Long
1 x MegaSquirt 3X Wiring Bundle - 12' long
1 x JimStim v1.5 MegaSquirt Stimulator w/ Wheel Simulator - Unassembled
2 x Metal DB37 Cover with Hardware & Gaskets
1 x MegaSquirt-III MS3X Expansion Card
1 x MegaSquirt-III w/PCB V3.0 - UnAssembled Kit with black case

... for my 5S-GTE build (+98 Camry block, Caldina head)

Hi,
I cannot believe that you spent all that money and time to build an engine and then buy this shit for controlling it. Man...you are brave. Megashit has a shitload of troubles with air tem compensations and ignition drift!
Best luck to you man.
H

No need to PM me that Hic
If it does have those issues (and i doubt it), they can be fixed, hence the attraction to MegaSquirt for most of us.

[Hic]

If these can be fixed, they would fix it already.

[MWP]

Im at the bench testing phase now...





Somehow i seem to have killed the 2nd trigger output of the JimStim so i cant test my intended setup properly (36-2 with 1 tooth cam wheel, both VRs).
Ill probably build up a spare AVR micro to do the VR trigger simulation duties and patch it into the JimStim.

[tw2]

Does anyone have any recommendations regarding setting up the idle control? I can't believe I am still working on this project as a whole, working full time in winter takes away any and all playtime. This is the last part until dyno tune. Anyway I have the stock idle up valve on the throttle body. I have the 50w 40ohm resistor inline with ground and the other wire going to MS pin 30.

I have it set to PWM warmup in tuner studio- is this correct?

I really need to start again with the whole thing. Should I disconnect the idle electrical plug and use the throttle screw to adjust the idle once the engine is warm?

Can anyone post their MS settings for the warm up table to give me an idea what I am aiming for?

Should it be set to 0% is open or 100% is open? I am confused since I thought the valve is moderately open with no input from the ecu at all?

Any help appreciated, thanks guys.

[BNZ]

Did you try this setup : viewtopic.php?f=9&t=31249&start=255 ? (last post)
Mine works just fine with this small circuit !

[tw2]

No I haven't tried that. I can go to Advanced, Idle valve test and then if I increase the iac steps the rpm will increase. I think that proves that it works?

Should I be able to control the warm up idle using idle PWM duty table alone? Maybe I just need to play around with it more.

[BNZ]

ofcourse,if it raises the rpm that's a good sign,although while I've bench tested mine using the simple,normal circuit like you have, the valve was not moving all the way,in fact it was moving let's say 30-40% from the total 100%,so i was able to feel rpm increase but not much,just enough to fool me that it works.

[tw2]

Had another play around with it. I can get the idle up to 2000rpm (probably more but didn't try). It will now nicely taper down from 1400 to 1000-1100 which is where is seems to sit the best. Cold start is good. I think my problem is that starting it again while in the process of warming up is causing some problems. I think I am ready to have it tuned by someone who knows what they are doing. It starts and is perfectly driveable otherwise.

Just waiting for my new trigger wheel from racerX

[pit_celica]

I suppose you are using 'PWM Warm-up Idle Control'. If it's acting like you want when running, but you are having problem when starting, play with the settings in the 'PWM Cranking' table. It's certainly your problem.

When you're done with it, try running it in closed-loop.

Sam

[tw2]

Thanks Sam. Yes I am using PWM warm up idle control. If I click on "PWM idle cranking duty" it brings up a table with

Coolant C Duty %
-40.0 50.0
10.1 30.1
48.9 19.9
71.1 19.9

I have never adjusted this table, it might be from the original msq file you sent me ages ago to get my car started. Do you have any suggestions on what to change?

Is PWM closed loop better? The PID (don't know what this means) settings look quite complicated.

[pit_celica]

Ok,

To tune this table, the best thing to do is to do a datalog while the engine is idling from cold start to operation temp. Be sure to datalog coolant temp, RPM and PWM % duty.

After, look at your log and, by example, at 20°C, if your RPM is 1100 and your PWM % duty is 15%, set the according value in the cranking table to 5% more duty, so 20%. This way, next time you will crank your engine at 20°C, it will open the idle valve at 20% and it will slowly ramp down to your 15% value to reach the said 1100 RPM idle speed. Do this to cover the whole warm-up temperature range.

As for closed-loop, read this at least 3 time (lol) :

http://www.msextra.com/doc/ms3/Idle_Control.html

I suggest you to tune the open-loop (PWM warm-up control) nicely before trying to use closed-loop. This way, you will know what kind of PWM % duty you need to reach a specific idle speed.

Most of the closed-loop settings are conditions to met to be in closed-loop idle control. These are the hardest to fine tune. PID terms are quite easy, trial and error.

For sure, read the link above to know what each settings is for.

If you want, I'll give you my .msq file so you can take a look at my settings.

Sam

[tw2]

Thank you very much for the explanation. I will read this through a few times.

[tw2]

I have fixed the warm start problem with your advice, it now starts well at any temperature. I still cannot get the idle nice. I can get it to idle at 1000rpm warmed up but it sounds like it wants to die. AFR is 14.0-15.0 and ignition timing is 20.

Sometimes if I start it warmed up ie above 70 degrees C, it will idle at 1600rpm for no reason well above where the PMW tables go to. My PMW tables end at 70 degrees C and 0% duty.

Could you please let me have a look at your msq?