Lotta fun with Megasquirt, Autotune, tunes while you drive Options

[yarin]

Wow.. those guys are certainly cranking out some amazing additions to their lineup. The router board should be a neat addition allowing for more input and outputs.

Things us 914 people can do:

External oil cooler flow control & temperature/pressure monitoring.

Cold start fan block servo. i just came up with this one.. instead of using the original heat-expansion cold start block off it can be connected to a servo or solenoid.

Fuel pressure info.

Then again one of the reasons i found the 914 so attractive was its simplicity (no power anything, simple, light, to the point).

Guys I have a question about my MS plan:

How reliable / easy would it be to implement spark advance/timing control using MS II triggered from a Pertronix type optical or magnetic pickup on a stock dizzy. Can this signal be used to trigger MS? I've heard several people experience a noisy RPM signal coming from the negative side of the coil.

Has anyone here run MS Ignition on a stock dizzy (advance locked) with a stock coil?

Here is the page for using the high current driver: http://www.megasquirt.info/ms2/vb921.htm

MS has a dwell parameter. Isn't the dwell set by either points or the slot in the optical pickup disc? Or does MS just read the first rise of the waveform and set its own duration?

I found this potential problem on the MS site:

"51. As we noted in step 50, there are two input circuits for the tach signal. One takes the square wave input from a hall sensor, optical sensor, or points.

This is also used if you want to trigger off the negative side of the coil, since the points control the negative side of the coil's primary circuit. However, you can only trigger off the coil's negative terminal if you are NOT trying to control ignition timing. " located in here: http://www.megasquirt.info/ms2/V3assemble.htm

Has anyone with a noisy tach input tried this?

"If you are going to use the negative side of the coil to trigger MegaSquirt (I.e., you are not using ignition timing control), then install and solder C12, the Ed capacitor (399-2017-ND, 0.001 µF, 102 marking}. Otherwise leave the C12 location empty - DO NOT jumper it. This is located above "Bowling" in the copyright notice. The value of this capacitor may need to be increased if there are noise problems with the tach signal - values up to 0.1uf will work. The 0.001uf value is a good starting point."

Thanks! I want to plan out my MS project and target any issues ahead of time before jumping into it.

[Hydra]

this topic is getting more interesting by the minute, i'll be waiting for all the info you guys are gona pour in... (IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif)

[DNHunt]

Yarin

I wish I could help you but, I'm running EDIS now. I ran MS with fuel only and a Pertronix triggering a MSD 6A for a while. The tach imput came from the Pertronix if I remember and it was fine. Of course the dizy was contolling timing. I will have to look at my wiring diagram tonight.

Ask on the MS sight. There's always someone to help you.

Dave

[yarin]

Thanks for the response Dave. I posted my questions here: http://www.msefi.com/viewtopic.php?p=95991#95991

After reading and reading and reading it does sound like we can use MS II configured with the high current coil driver and and either points or equivalent (optical, hall, VR) using a stock locked dizzy.

It sounds like MS would pickup the positive edge of the waveform and control dwell and advance among many things. Advance can lead the leading edge of a spark event and output directly from MS to a stock coil. It sounds like the noisy input problem is easily solved with the Ed Capacitor(C12).

Any comments? Do I make sense or am I dreaming?

If this works it is WAY easier to implement than EDIS.

[yarin]

I learned a hell of a lot from this post regarding comparing 914 dizzys to crank fired. Check out this thread, link at the bottom.


QUOTE (Mueller @ Mar 17 2004, 04:53 PM)
I was wondering what the crankfire has over the distributor ignition besides 0 moving parts that can wear out.

Hi Mike! Wow, what a coincidence. Guess what I just did? I just came in from driving my 914 for the first time with crank-fired ignition! I can see it in the papers now "Monkey sucessfully fabricates hall-effect crank possition sensor for 914"

Seriously. Remember a few years ago when I was trying to fab a crank possition sensor with magnets mounted in the rim of the fan pulley? Well the failure of that project has been bugging me for years so tonight I went out to the garage and dug out all the pieces and tried again. It wasn't the physical design that was the problem it was the wiring. This time I shielded the signal leads all the way to the ECU and bridged them to +12v with 1k ohm resistors so that when pulled to ground they would make a nice crisp square wave. It worked! Engine fired right up, I set the timing baseline with the laptop and went for a drive. It was sweet.

If you recall I was previously running a Crane optical sensor in the dizzy. With the optical trigger there was much less spark scatter than with points, but there was still a noticeable amount. I think it's probably because even with a tight dizzy there is gear lash between the dizzy shaft and the crank, not to mention dizzy shaft wobble. I bet at idle speed that dizzy shaft is rattling back and forth across that gear lash. Running off the crank-trigger there is much less spark scatter as viewed with the timing light. The engine definitely idles more smoothly. I don't expect that there is really any more power - maybe a little, or like has been said - the potential now to extract a hair more, but nothing earth-shattering. It definitely seems smoother though, and I like that. It's still firing through the distributor for now (for spark distribution only - not timing or crank possition). I've got the coils for waste-spark but need another compatible ignition amplifier. As soon as I round one up I'll try to go distributorless and see what happens.

-Ben M. (now with new improved crank-fire action)

http://www.914world.com/bbs2/index.php?act=...f=2&t=10134&hl=

[Rocky]

Yea Dave, we do need to get together. I work way too much and rarely have computer time to look on the site. Ill give you a call and drive to see your beast or let me know next time your going to Bremerton.
Cant wait for warm weather and WCC.

GO SEAHAWKS!!! beer2:

Tim