MicroSquirt: 4AGE 20V Distributor Pickup for wasted spark

tineira · Post by **tineira** » Wed Jan 02, 2008 10:10 am

Hi,
I am installing a 4AGE 20V on a Toyota AE86 using MicroSquirt. There is a clearance issue between the distributor and the firewall, so I decided to use only the VR Sensors and toothed wheels of the distributor, and run wasted spark.

The distributor has 2 wheels inside, and 3 VR sensors. One sensor goes to a 24 toothed wheel REF, and the other 2 sensor to a 1 tooth wheel, placed 180deg apart to do the sync. Each one of this VR Sensor have its individual output from the distributor, so I can choose which ones to use.

I attached a pic of the sync wheel.

Now this is my problem, there are 3 options to run the engine:

1)Use the 24 toothed wheel as 12-0 crank ref and ONE vr sensor on the sync wheel.
2)Use the 24 toothed wheel as 12 crank ref and both vr sensors on the sync wheel as crack sync.
3)Use only the 24 toothed wheel, removing 2 teeth 180deg appart, and use it as a 12-1 crank wheel.

I prefer options 1 or 2, that way I don't have to remove teeth from the ref wheel.

The problem using option 1 is that it is not completely tested yet: http://www.microsquirt.com/viewtopic.ph ... highlight=

I would prefer to use option 2 (N-0 wheel with crank sync), but don't know how to wire the 2 VR sensors to the MicroSquirt. Is it OK to just wire this cables together into one wire going to VR2IN+?

Thanks for any input on this.

Matt Cramer · Post by **Matt Cramer** » Thu Jan 03, 2008 9:51 am

I'd try option 1 first and see how that goes - option 3 is the most well tested example, and would provide a good fall-back.

tineira · Post by **tineira** » Thu Jan 03, 2008 11:01 am

Thanks, it's the logical way to do it.

But I have another question, would I damage something, or get a nosy signal if I just wire both SYNC sensors to VRIN2+? That way I would be able to use option 2

.

If nothing could get damaged, maybe I would try option 2, then do as you say and test 1 and at last 3.

BTW, thanks for the super speedy ninja shipping on my MicroSquirt

Matt Cramer · Post by **Matt Cramer** » Fri Jan 04, 2008 9:05 am

I think option 2 could work, and don't think it's likely to hurt anything to try - are you trying to make it sync up faster?

tineira · Post by **tineira** » Sun Jan 06, 2008 12:37 pm

I was trying to leave the distributor unmodified, because it is a risk to trim some teeth of the wheel, but none of the other options worked, so I just trimmed the 2 teeth, and got a perfect RPM signal right away.

Just to confirm, I am sure that the signal generated by the VR is a falling edge signal, does this mean that I have to use "Rising Edge" on the MicroSquirt? It seams to work with no problems with this settings.

tineira · Post by **tineira** » Tue Jan 08, 2008 3:41 am

This is a video of the car when it started for the first time.
http://www.youtube.com/watch?v=CKdob-HHwGs