ok, my tach in only showing 1/2 the true RPM and the t1 is firing correctly (confirmed with timing light) and T2 will not fire at all. We've tried several different coils and its the same result. It also will not even fire the T1 under 800 rpm. Any ideas?

 

Its not meant to fire the trailing coil below 800rpm. It is disabled in software because there is a bug that would cause a miss as the rpm crosses through 800rpm.


Try setting up the coil on a bench and see if the toggle works.

Pink is Fire
White is toggle
Earth the metal plate on the T coil

 

ok, well I think we figured some of it out.... some of it had to do with the Dwell settings. I found on here that toufuball (i think) had
5
2.6
.5
for the dwell settings, I had a 5 instead of the .5.
But now the tach (and I assume the T coil) jumps around quite a bit, sometimes it will show 1/2 actual RPM. Like if I'm ideling at 1200, the tach will show 600.
Any more ideas? and are my dewll setting correct? And are there and other settings that would affect this?

-Thanks

 

What is the Voltages needed to test Fire and Toggle

 

Sounds like you may either have the coil select signal and the IGt-T signal backwards, or you've got a problem with a loose wire.

Ken

 

I just used the car battery. So 12V works and it didn't seem to damage my coilpack.

I'm pretty sure the megasquirt toggles between 0V and 5V.


For eg.

Join the two tan wires to the battery.
Use a wire with lugs on the end as an earth strap to the battery/chassi YOU NEED TO EARTH THE BODY OF THE COILPACK!

leave the white wire hanging

touch and release the connection fromt he red wire to teh battery and one of the coils should discharge.

next join the white wire to the battery.

touch and release the red wires connection from the battery and the other coil should discharge.

 

Well we think the wires where backwards the first time because the T coils would not fire at all, then we swapped them around and now they fire.

BTW both T1 and T2 are firing now, but the tach is still acting weird in low rpm areas.

 

Yes, we thought the T2 coil wasn't firing probably because of a bad timing light connection.

But why would I be at cruise and the rpm as indicated by the tach would drop to 1/2 of the true rpm?

 

Your trailing ignitor might be bad...

If you're getting the proper spark, that's the only thing I can think of that'd be different.

Ken

 

The ignitor is part of the acutal coil right? I changed the coil and I assumed the ignitor was in there too but I might be wrong.

Also I did some more investigation with the timing light, so here is some more insighgt:
Ok, I locked down the advance to 0 and the split to 0.
Both the Leading coils were firing at 0 but the T1 was roughly 20deg advanced, shouldent it be at 0 also? shouldent the T1 and L coils be firing at the same time if there is no split?
Also, how far apart should the T2 be firing from the T1? like, if I had a digital timing light I could check that too.
About the T2 Coil: When I hooked the timing light to the T2 coil I saw that is was not firing below about 1500 RPM, this explains the weird tach behavoir. So what would cause the T2 coil to not fire below about 1500 rpm and the T1 to contine firing all the way down to 800?

 

Nothing in code would cause the problems you're seeing. Most likely you have something wiring related inside the MS or between the MS and the ignitors messed up. You have pullups on all the LEDs, have the middle LED wired to coil select, and have the right-most LED (looking at the front of the box) wired to the IGt-T signal? You don't have spark output inverted do you?

Ken

 

hmm, no there not reversed. They were reverses and it didn't work at all.
I'll be checking the board wiring as well
hmm..........

 

Also, would a grounding issue cause this issue?
I read that the T coil is grounded through the back plate but my backplate seems to be suported by a rubber block... its all stock.

 

as long as there's metal to metal contact bolting the coils to the ignitor, and the ignitor to the chassis, then grounding shouldn't be the issue...

Did you verify that you're not running inverted spark outputs in MegaTune?

Ken

 

no, I don't think I saw an option like that. I found the FD vs. FC option, and mine is on FC, but I never saw an inverted spark output setting.

 

It's in the Spark dialog, same one where you set the trigger angle.

Ken

 

ahh ok, I found that and its set to NO.

 

OK, then that shouldn't be the cause of the problem.

This really only leaves wiring or a bad ignitor.

Ken