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Megasquirt ignition problem
clairetoo - 24/8/13 at 10:54 AM

I've been having a bit of trouble mapping my Mx5 - Ms1/extra + edis - with poor fuel consumption and constant spitting back through the throttle bodies .
While trying a bit of mapping with a fresh ignition map , I noticed something odd - while the ecu is following the map , the actual timing isnt ?
It got so bad that timing at tickover dropped from 13 degrees to less than 8 , lots of pops and spits , and revving would only get about 12 degrees when the map was showing 28...........
I've swapped the edis for a known working one , and no change - WTF is going on ?


dave_424 - 24/8/13 at 11:06 AM

I don't know much about EDIS with megasquirt, however there is a setting called "tooth number 1 offset" which you have to adjust so that the number in the spark table is the actual timing that is getting to the engine. I would suggest setting the ignition timing to fixed at 0 degrees, then with the fuel pump and injectors disabled, turn the engine over with a timing light and make sure that the timing marks are lining up.

With that all checked, make sure in megasquirt that all your sensors are reading correct, because there are certain values that can change the ignition timing e.g. too high IAT will retard timing, too low coolant temp will engage cold advance that will advance timing etc.

Feel free to email me your .msq tune file and also see if you can get a datalog of when things are going wrong and send that as well.

Dave_424@hotmail.co.uk

Dave


r1_pete - 24/8/13 at 12:48 PM

It sounds like the SAW signal is either not being produced, corrupted, or not getting to the edis.

If you disconnect the saw pin, you should get a constant 10 degrees limp home advance.

Check your connections, and the air gap between the trigger wheel and sensor, the latter may not be an issue if you are seeing condition changes in megatune.


ashg - 24/8/13 at 02:20 PM

ditch the edis and run the bip373's


dave_424 - 24/8/13 at 02:26 PM

BIP would be my choice and did that on my set up, however EDIS will do a limp home 10 degree timing which would be useful on a road car.


clairetoo - 26/8/13 at 11:03 AM

Well.............I checked the timing (even as far as pulling a spark plug to check the TDC mark) and it was good - but it was still spitting back and not wanting to tick over .
So I hit autotune on the laptop - and went for a drive . It immediately richened up most of the map and started to run a whole load better . Which was odd , because it was running fine before .
I still dont know what was wrong with it - every time I have tried to auto tune it before , it has leaned off to the point of barely running ?

Oh well - better just enjoy it while the sun shines


JPSeuropa - 27/8/13 at 04:22 PM

sounds like you may be on the right track, but post a log and msq either here or on the MSextra forums so that there is DATA!


clairetoo - 27/8/13 at 04:35 PM

I wish I had some idea how to do that - computers are not my speciality , plus I cant work out how to connect my tuning laptop to the internet........


snapper - 27/8/13 at 04:45 PM

Put USB memory stick in tuning computer
Copy map/data to that
Plug USB stick into Internet computer save to folder


BaileyPerformance - 27/8/13 at 08:21 PM

Are you sure you have your trigger wheel fitted correctly? We see loads aligned incorrectly.

Also check the ignition setting in tuner studio, from memory should be INVERTED and RISING EDGE. Set dwell to FIXED DUTY.

Trigger logs are of little help when using Edis as the trigger is just a pulse.


shaunod - 12/9/13 at 09:42 AM

If you are getting 'chirps' back through your throttle bodies you may well have an air leak / balancing issue on the throttle bodies ... that would also explain the change in fueling.

Also check that your air temp is reading correctly .. if it reads really high it will lean the mixture considerably, it thinks the air is really hot and therefore less dense.

Shaun


daxtojeiro - 12/9/13 at 12:42 PM

It could be that the wideband output settings are not actually giving the ECU what it expects to get. MS1 is a weird beast for getting AFR and Temperature measurements into it, as the displayed values are not the values the ECU see's.
We had to use inc files to convert the ADC to a real time value.

I would check the settings in Tuner Studio (Project Properties) and the output settings for the wideband to ensure they match.
Also that the AFR table is enabled.
See my help files on my site for info on how to do these checks,
Phil

[Edited on 12/9/13 by daxtojeiro]


matt_gsxr - 12/9/13 at 12:47 PM

quote:
Originally posted by daxtojeiro
It could be that the wideband output settings are not actually giving the ECU what it expects to get. MS1 is a weird beast for getting AFR and Temperature measurements into it, as the displayed values are not the values the ECU see's.
We had to use inc files to convert the ADC to a real time value.

[Edited on 12/9/13 by daxtojeiro]


Agreed, Ms2 is so much nicer in that regard.