megasquirt

[zukitek]

I finally got my issues with my microsquirt module worked out (it was faultyand had to be replaced)and the car runs and I have got it tuned well enough to drive around . Got a couple things I havent been able to tune out .

1)The dash tach is not functioning correctly. It works at low engine speeds (innacurately) and drops out to 0 at higher RPMs mostly under high acceleration pulls.

2)started kickback during startup but I didnt have a timing light at home when I was setting everything up so that might just be a matter of verifying that I have the correct trigger offset in the tune . Its presently at 108 degrees. The cranking advance is set at 0 degrees.

[TouringBubble]

Sounds to me like the MS is expecting a different voltage for the tach. Look for a voltage scaling for RPM, something like 0.3v = 500 and 4.8v=9000. Never used MS but that sounds like a plausible issue.

[Cholewa]

Are you still running a distributor or did you switch over to wasted spark?

If you've got a dizzy, just run the tach through the coil instead of through MS.

[zukitek]

Im presently using a hall type dizzy but the tach is ecu driven and is not designed to run off of the neg. side of the coil . I am pretty sure the problem is in the noise filtering setting though and like Matt said about the configuration of low and high voltage settings.

[engled]

Ricky, I thought the trigger angle/offset should be ~44degrees.

The tach output was disabled in your config. In TS go to "Extended" then "Tach Output" and see how it's set up.

I think it should be set to "on", "Tach out" and maybe "half speed"

[zukitek]

Darryl, the crank offset was way wrong . That 44 was the default that you end up with on a base tuner studio start up. The excel file for the s13 and the sr20 base tunes were 112. I opted not to use either of those tunes . I just started off with a generic one size fits all and went forth. I also found that D14(prefered) wont run my car. I had to change it to js10 in "more ignition ".

The tach signal has been resolved. It turns out that it is a digital signal and is identical to the one coming out of the CAS so it was just a matter of running a short jumper from the tach signal wire to pin 44 which is opto+. Works great.

Still got the kickback issue but today at work I set the MS to fixed timing @0 and checked the ignition timing with a light and it was at TDC"0" on the pointer so I guess my ear tune of the trigger offset wasnt too shabby. I have my cranking advance set at "0" so it should have absolutely no reason to preignite mechanically. I emailed Matt at DIY today about it and he says they sell a trigger wheel that bolts right in to my dizzy that has better resolution for 25 bucks . This may be my next route. The down sidw is that this adds another step to going back stock ecu. I dont like that . Right now I have that safety net of PNP between stock and MS. If I go with a differant trigger wheel then there are tools involved...No guts no glory I guess.

I have put about 50 miles on it so far ...mostly in traffic but some interstate too under varying throttle loads and according to my wideband guage it is pretty solid between 13-15 afr at light throttle cruise and 12-13 under heavy acceleration. IAC was an absolute snap...its almost perfect at all temps. I am still struggling with the accel enrichment curve and still need a touch here and there on the warmup enrichment curve.

I still have yet to toy with the timing curve at all. This is now becoming fun.

[zukitek]

24-1-1 trigger wheel ordered and wiring has begun for COP wasted spark using LS1 coils. This is going to mean I will HAVE to get the tacho out function working correctly . I found that I didnt have it enabled ...like Darryl said ...duhhh

[engled]

24-1-1 trigger wheel ordered and wiring has begun for COP wasted spark using LS1 coils. This is going to mean I will HAVE to get the tacho out function working correctly . I found that I didnt have it enabled ...like Darryl said ...duhhh

I do have a copy of your tune on my laptop

[zukitek]

Now since I know that changing the trigger wheel from the factory nissan CAS wheel to the 24-1-1 wheel is going to kill my tach again and force me to do it right and switching to COP is going to require a second trigger and some more outputs, wiring,and megasquirt PCB mods... today I did the following:


First I disconnected the jumper from factory harness adaptor board pin 3(tach lead) and pin 40( cam sensor reference)....reconnected the tach lead on the PCB and factory harness adapter pin 3.....in tuner studio,set tach output to on ...set output to D14 on normal speed and the tach works normally.

Next I mounted all 4 LS1 coils to the v/cover...built 4 hybrid coil wires with LS1 on 1 end and nissan KA plug boots on the other...then on the PCB, I jumpered 5volt controls cyl1=IG1,cyl2=IG2,cyl3=WLED,cyl4=ALED to pins 1-4 of the 15 pin on the PCB and ran pin 5 of the 15 pin to signal ground on the PCB.

Next I installed 100ohm pullups on R1&R2 to 5volts to prepare WLED and ALED ,jumpered factory harness adapter board pin 41(cam sensor signal) to PCB pin VR2 and installed a 470 ohm pullup to 5volts on R4.

Next I built a harness to plug into the 15 pin with the (4) 5 volt controls and the low reference and routed to the engine compartment. I then jumped from the OEM dizzy positive coil connector and engine ground to provide power and ground to the LS1 coils .

Now I'm just waiting on the 24-1-1 trigger wheel via snail mail and a connector from the salvage yard to connect the coil assembly subharness to the harness I ran today. I swear ...I wish DIY would use UPS instead of USPS. It takes like 1-2 days longer to get here.

BTW....In case you guys haven't noticed ...I'm using this thread to think out loud and show my work so to speak . Maybe some other guy who might be half the noob I am at building a Megasquirt can google his way to this thread one day and find something totally useless.

[zukitek]

I do have a copy of your tune on my laptop

The thing is ...thats not even the tune that cranked the car in the first place. The other thing is ....we never tried JS10 instead of D14 to fire the ignition when I was over at your place . Who knows.....

[zukitek]

Does anyone running megasquirt with COP wasted spark know what order "ign1,Ign2,WLED,and ALED" outputs go to the ignition coils 1-4? Would it be #1=ig1,2=ig2,3=WLED,and 4=ALED?

I know you have to go by the firing order on sequential but Im unsure about wasted spark.

[JohnW8]

I think mine were ign1 for coils 1&4 and ign2 for coils 2&3...I think.

[zukitek]

Finally go the wasted spark setup to work (some idiot was loading the wrong firmware (MS2 instead of microsquirt) doh!!!! The LS coils are a very much needed improvement . It certainly doesnt take much dwell to operate them well. I took it all the way down to 1.1 MS with no misfires. That is as low as TS will let you go .