Megasquirt Installation Continued...

IGNITION
I initially tried to get the car running on a Jaycar HEI (high energy ignitio) kit, which use the standard bluetop reluctor (magnetic) dizzy pickups as a trigger. I also had the Programmable Ignition kit, which would support 3 stage advance/retard, and boost retard with a suitable hobbs switch. Unfortunately it was not to be, with the HEI kit just not triggering. It would charge the coil but not trigger when the cam was turned. I e-mailed silicon chip, and was told by John Clarke that, "The reluctor circuit may need to be adjusted in sensitivity to work on your car. The 47k ohm resistor connecting from the cathode of the ZD5 zener diode can be altered for this. Use a 200k ohm trim pot and adjust for best results. Change the trim pot for a fixed resistor of about the same value."
Sorry John, but I never gave it a shot, though I had spent much time building the kit, running all the wires and grounds, and mounting it all in boxes nicely.
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So, I then tried with a standard bluetop 4AGE ignitor, as an ignitor document showed it to be possible. However, I think one might need the later generation ignitor, with the 4pin plug. Next...
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2TGEU-Ignitor, on fixed advance. Cheap as chips (free), and easy to set up. Attached the ignitor to the coil, removing the ballast (probably a bad idea later), and connected it up to the 4AGE plug. (2tgeu ignitors have notoriously bad trigger wire for soldering, plenty of solder and heat needed). It worked like a treat, charging and discharging the coil easily, even when turning the dizzy by hand. At this stage I thought I was nuts to have ever bothered with anything else to get it started.
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NB: I had removed the ballast, even the the coil said "use with external resistor" as my 2TGEU in my KE35 ran great without it, no problems whatsoever, even with the same coil. However, on checking today (19/1/04), this coil did get very hot over a short drive, and removing the ballast may have caused it to break down.
Timing was set around 10 degrees, as the car wasn't idling too well when it was first going, but I want to set it at about 20 degrees on the next startup.

- UPDATE - 21/1/04
It was the coil that was causing the missing. Bosch coil from wreckers was the trick.

- UPDATE - 10/2/04
Now running a Bosch GT40RT coil, combined with ballast resistor. I strongly recommend the ballast unless you like to be shocked by your leads. Timing is around 20 degrees, but I have to check it again next time it's running. I had accidently missed soldering the ground pin for the chip on the Jaycar HEI, which is why it didn't work. I had checked the board over and over and couldn't see anything, but a Andrew at Jaycar picked it up straight away, DOH. I may reapproach this later, as I think I can run MegaSquirt'n'Spark with this ignitor, ie: MS controls fuel map and igntion map, uses FIDLE output on MS.

- UPDATE - 15/2/04
Miss was caused by wires going from dizzy to 2tgeu module being mixed up. Must have happened when turbo was being put on. Anyways, that's all sorted now, and spark seems pretty strong. Base timing was at 20, but I've since dropped it to 15 to be absolutely safe whilst tuning. Probably not going to bother with programmable ignition for some time.

- UPDATE - 23/3/04
Back on 20 degrees base timing, which is a bit much for starting (5-10 better), but good to drive around on. I think I could run up to 25 degrees under boost, but don't have the Hall Effect module I need yet, which I will use with Redtop distributor.
Also, had a few spiking problems, as detailed on the previous page.

- UPDATE - 3/05/04
Looks like I could use two 2TGEU ignitors to control spark, with one ignitor taking the pickups in, and then sending the pulse to the megasquirt, instead of the coil to fire. Then the second ignitor takes a pulse from the megasquirt instead of the distributor, and triggers the coil when required.
But.... I might just play around with the Jaycar HEI again, as it has been used with the megasquirt before by a fella called Luke off the megasquirt'n'spark yahoo group.
"I were you the first thing I would try is to build it for reluctor triggering and use the tach output of Q3 to trigger the Msns and then use the msns with an inverted output to drive Q2 via a pull up resistor.This would give a 1 box solution with the fixed 0.9ms dwell.Should be cool but would need to run with time based crank timing.You will also have to trigger about 40 to 50 cam degrees earier than the factory trigger point. "
So, I'll try replacing the chip on it which I believe I burnt out then have another go. Means I can keep using the GT40RT, which will spark about 1.5". We inadvertantly tested this when the HT lead came off the distributor cap. ;)

Continue on at Tuning