Toyota VAST wiring difficulties

[slugbeast]

I'm using MS2 on a 4age from an 85' mr2 I'm swapping into my 89' corolla sr5. The issue is it didn't come with much wiring or a distributor, coil, igniter. I had to get the components off ebay from the U.K. (I'm in the u.s.) I can't find wiring for the things anywhere, I don't know what (supposedly two) wires of the three coming off of the distributor go to what wires on the ignitor, and I don't know what wires off the igniter go to the megasquirt. (Keep in mind I understand how megasquirt is to be wired I just don't know what the factory wires do) I can make guesses based on what wires are also attached to the positive and negative of the coil from the igniter and but that doesn't rule enough wires out, I'm stumped. I can't find diagrams for the anywhere.

Here are pictures of the components. Any help is greatly appreciated.

20130814_124159.jpg

20130814_124240.jpg

[nismoautoxr]

Ill see if I cn help from recollection of an old project long since gone. Since the factory wiring diagram only lists the wire colors on the vhicle sid of the harness...they do not correspond to the colors of the distr. and ignitor wires.

On the distributor you have 3 wires and thats easy to figure out . There is a single tooth trigger and a 4 tooth trigger . Both of these sensors are VR so no power supply needed there. One of your wires is going to go to The G+ sensor which is the 1 tooth trigger. Another is the NE sensor which is the 4 tooth sensor. A simple ohm meter should tell you which is which those the remaining wire is G-- ...IIRC its NE and G-- that you are going to be using for your crank trigger input to the MS....and the G+ is your second trigger if your plans are to be using sequential ...but as I say Im fuzzy on it and toyotas info to the aftermarket was attrocious back in the 80s .

The ignitor has wires that you are not concerned with because all you really are concrned with from the ms is sending spark A to the NE input of the ignitor....which is IGT in toyota speak. The IGF wire on the ignitor is only a reference that the stock ECU used . It is not used for MS. I wish I could be more specific on which one of your wires on the ignitor is IGT but its been a long time ago. To supply power to the ignitor you just wire a 12v switched source on the + side of the coil with the wire that is already there.

Ill give you some advice though that will save you alot of grief on firing the coil. just directly fire the coil with the MS and ditch the ignitor altogether and just use the distributor to trigger the MS . Matt Cramer and Jerry Hoffman can probably help on the ignitor wiring as Jerry built an 85 or 86 MR2 and he is intimately familiar with the ignitor side regarding the wirecolors and deciphering which one is which ... www.diyautotune.com if you go to that link there should be a technical assistance contact there . Good luck and drive well.

[slugbeast]

The reason I decided to go with the igniter is because of the tech article on diyautotune, this one; http://www.diyautotune.com/tech_article ... rt_122.htm but I'll do some more digging on that site and maybe try to get in contact with someone.

I guess if i decided to eliminate the original plan of using the ignitor I couldn't use the hall input I went to the trouble of soldering up? The ignitor is square wave and the VR from the distributor is sharktooth.

Since yesterday I've found a couple non-conflicting forum posts that state:
for ignitor
red-IGT or IGF
white-IGT or IGF
brown-power supply (goes to + on coil anyway)
yellow-Tach output (NE)
black-coil -

Distributor:
Red (+)
White (-)

Still not sure where the wires on the distributor go to on the igniter still though. (if I were to of course stick to my original plan)

[nismoautoxr]

Like I said ... the distributor wires do not go to the ignitor. They go to the computer as the RPM signal . The computer triggers the ignitor on IGT and the ignitor fires the coil. THis is the same arrangement , should you proceed in this direction, that you will use for the MS. If you made a hall to trigger the MS rather than using the VR sensors in the distributor then the wires on the distributor are irrelevant in that case.

In the car I built ....I used the system it had on it already for a short period then I just ditched the ignitor and single coil system and used 4 LS2 coils with short plug wires and fired them using logic outputs since those coils have built in ignitors . Much better running car that way and less hardware to be concerned with causing problems.

[nismoautoxr]

muythaibxr on this forum I believe is a Toyota guy and is one of the code developers and forum moderators ...perhaps he could give you a bit more specific and verified info than I . Good luck with the project

[Matt Cramer]

Does your distributor have a 4 tooth wheel and a 1 tooth wheel? If you have something else, like a 24 tooth wheel and a 1 tooth wheel, this is not VAST at all, but a later system:

http://www.msextra.com/doc/ms2extra/MS2 ... utors.html