Problem with switching from points to electronic distributor

[Mark]

I'm replacing the points-type distributor on my '81 Tercel sedan with the IIA electronic distributor from the 2nd gen Tercel. I already installed the IIA distributor into the '81. It fits perfectly. My problem is the wiring. I wired the new distributor to the + and - wires going to the external coil which was part of the old distributor system. When I turn the key to start the car, it starts fine and the cylinders fire. When I release the key and it goes back to the "on" position, the car immediately dies. The distributor is only getting voltage when the key is in the start position. I checked the voltage going to the distributor on my '84 wagon and it's getting voltage when the key is in the "on" position. The problem is that I don't have the wiring diagram from the 1st gen Tercel so I can't figure out where to connect the distributor so it gets voltage when the key is in the on position. I don't suppose anyone has done this conversion (probably in Canada since the 1st gens in the US had the more modern electronic distributor to begin with) and would know where to connect the wires?

[irowiki]

1980 had the points. I have a wiring diagram in my 1st gen tercel book, would that help?

[Mark]

It definitely would. I'm trying to find one online, but they're all just tiny images from people trying to sell them. My Hanes manual only has the wiring diagram for the transistorized electronic distributor. I guess they figured that the old points-type was so simple any idiot could figure it out.

[irowiki]

Hmm, mine is a haynes as well. 1980 thru 1982, 92040 in the top right corner. Same book?

[Mark]

Oops. Mine's actually the Chilton's "repair and tune-up guide" for Corolla/Carina/Tercel/Starlet 1970-1983.

[irowiki]

Ah ha!! Okay let me try scanning it. Brb.

[irowiki]

https://drive.google.com/file/d/0B747Qy ... sp=sharing

Page 1 is 1980 page 2 is 1981 let me know if you need more of it!

[Mark]

Thanks alot! That's exactly what I need. I'll have a good look at it after work today and compare it to what's under my hood.

[irowiki]

When the scanner is actually working I'll scan the whole diagram for you.

The hayne's manual for our 1st gens is amazing, let me know if you might need anything else in it.

[Mark]

So thanks to Irowiki's wiring diagrams, I think I found my problem. The 2nd gen Tercel's IIA distributor only had one power (12v) wire involved. The 1st Gen had 2 power wires (one for the key in the starting position and one in the "on" position). The 1st gen has a 6-volt coil while the 2nd gen has a 12v. In the 1st gen, one of the power wires (12v) sends the full 12 volts to the ignition system during start up to ensure a big spark. During normal running (key in the "on" position), the power is routed through a resistor that drops the voltage to 6 volts. I assume that a full 12v would burn out the coil during extended operation. So now my problem is how to combine both of the power wires from the ignition key and join them into one wire (always giving 12 volts) to power the IIA distributor. I'm hoping this won't cause any arcing/burned wire smells/blown fuses/destroyed car/etc.

[dlb]

can you simply find and remove the resistor that drops the running voltage?

[Mark]

Yes, I'd have to remove the resistor from the circuit, but the 2 wires from the key still have to be connected together. I just did this a few minutes ago. There was no arcing or anything. I connected the 2, now 12v wires together and wired it to the new distributor. It started and ran fine. I took it for a quick drive around the block and it didn't explode. I checked the timing with the timing light and it showed about 4 degrees BTDC even though I manually set it for about 7 degrees. Disconnecting the vacuum hose didn't make a difference and it didn't seem like there was any vacuum coming from the hose at all. I reset the timing for 7 degrees BTDC (according to the timing light). I need to take it for a longer drive, including the highway, but I don't want to risk using it to get to work tomorrow just yet.

[Mark]

I took it for a longer drive today, including the highway and all is still well so I can go back to using it as a commuter. I'm curious to see if the electronic ignition, higher voltage and better spark improve the fuel economy.
-Thanks again for scanning and posting the wiring diagram Irowiki!

[Mark]

I also noticed an intermittent "missing" during acceleration for the last week or so before and after I installed the new distributor. Yesterday I replaced the spark plugs and 2 of them had a crack all the way down the ceramic insulator. With the new plugs, the missing is gone. A couple of years ago I had a much worse hesitation/missing problem on my wagon that turned out to be the plugs too.