megasquirt for dummies

[thewestie]

I finally got a minute to look at the car. I loaded 3.4 and started to get the car to idle it wasn't as easy as the first time I couldn't get it to run good and I loaded old tune and updated firmware. Wanted to hit the last cruise night of the season 1st and last for me. car ran great on way there ran auto tune and cleaned up afrs a little by hand and thought I was good to go. Ride home was going lean when I touch the throttle pretty sure its lean from a miss. I logged a lot on ride home. I have to figure out how to shorten logs or load bigger ones.

[kjones6039]

I have to figure out how to shorten logs or load bigger ones.

Logs can be truncated using MegaLogViewer. Right click on the graph and select Log Editing.......

Of course you can ZIP reasonably sized files also.

Ken

[thewestie]

I've found a spark plug wire grounding to the header. Can feel a slight miss when softly rev at low rpm. Wires are 5 years old. Gonna change them out ordered some today.

[ajay]

Hi guys,

I don't know if this is the right place to post my question! but I am a beginner to all these stuff, so please help me out.

Can someone explain me how ignition mapping is done (in detail) and the mathematical relations behind this. I want to start from the scratch please give me a link to learn all these or guide me in any possible way.

Thank you in advance

[thewestie]

This isnt really the place the is a tread I started for help on something that was frustrating me.
Try posting in tunning help section
Good luck.

[thewestie]

Changed plug wires. Checked and rechecked during order and still getting a lean miss. Plus are gapped at. .32
Gonna recheck timing and maybe new msd cap an rotor. ,

[thewestie]

New cap and rotor rechecked timing at matched it to tuner studio it was off by 4 degree. Still does same thing when cruising in high gear and 14.1 arf's 1200 rpm touch throttle it goes lean from missing I can feel it in the seat of the pants.

[Matt Cramer]

Do you have a data log of the miss after all the latest fixes, etc were applied?

[thewestie]

Just made one in drive way can see it going lean from miss
thanks

[billr]

It looks to me like the AE is too aggressive and it is going too rich when you open the throttle. You do know that the WB will show lean when there is miss-firing, whether the miss is caused by too rich or too lean (or bad ignition), don't you? You can't always accept WB AFR info at face-value.

[kjones6039]

Pretty hard to discern anything with all that throttle movement. Just curious..... is all the throttle jacking necessary to keep this car running or are all those oscillations caused by something else??

Ken

[thewestie]

I knew how the wb would interpreted the lean reading from a miss. Didn't figure on rich miss fire. Ill look at leaning out AE.Thanks

[kjones6039]

I knew how the wb would interpreted the lean reading from a miss. Didn't figure on rich miss fire. Ill look at leaning out AE.Thanks

Still wondering about all those oscillations..........

Ken

[thewestie]

Hi Ken the car will idle steady without touching the throttle. Its just how I was trying to demonstrate the lean afr. when gently cracking throttle .
thanks

[kjones6039]

Hi Ken the car will idle steady without touching the throttle. Its just how I was trying to demonstrate the lean afr. when gently cracking throttle .
thanks

OK... Got it!

I noticed in your MSQ that your AE threshold is 200..... Kind of high IMO.... For comparison, mine is 12

If this was mine I would turn DE off until I got it sorted out........ It looks to me like DE is contributing to your lean condition........

Just a couple thoughts and observations.

Ken

[thewestie]

I'll look at that too.

[turbo conversion]

I agree with Ken, AE threshold is very high mine is 65 and I would set Decel Fuel Amount to 100.

I do think your AFR table needs some smoothing mainly in the crusing are, there is a 14.9 in the middle of lower numbers.

The other thing I see is your timing I think is very aggressive, 28 deg. at 1500 rpm seams high to me.

I would suggest another data log with some steady throttle then some throttle movement,
then steady throttle again to let everything settle down. It will make it easier to see what is actually happening.

David

[kjones6039]

I would suggest another data log with some steady throttle then some throttle movement,
then steady throttle again to let everything settle down. It will make it easier to see what is actually happening.

Yes, a steady state log with occasional acceleration should prove most helpful!

I am also curious about why you are using 14.2 AFR in your Req_fuel calculation and your General Settings.

Ken

[thewestie]

HI Ken I'm using 14.2 because that's what I was told to use? 14.7 Stoich? I have no good reason.
I started new tune to get rid of old barro corrections to go with last firware. I played with accel enrich and went for a ride I think I'm on the rite track.I have a little bucking but no lean miss I feel a miss at 2500 to 3000 rpm. Ithink that me be timing. I pulled out some timing all around. Like David said about timing and ve tabele all need smoothing. I havnt figured out what that means yet.

[kjones6039]

Your log is looking better, IMO. Go ahead and change those 14.2's in your MSQ to 14.7. There is no good reason for them to be 14.2 AFAIK.......

I still recommend turning DE off (set t0 100 to turn off) for the time being. I would also suggest setting AE Mapdot to 1000 in order to get it out of the equation.

Ken