converting ignition to electronic

[khughes]

Hi Guys,

i managed to get an article describing the wiring installation of an RB20DET into a C210 Skyline (thanks to Jim), complete with EFI, ECU etc..

one of the problems they faced was that the ignition on signal was interrupted (i assume when it gets switched back to on) and caused problems keeping the ecu running.. they mentioned they had to convert it somehow using relays..

any ideas what this is about or how to get around this? i know i will hit this problem very shortly!

[kyteler]

Hmmm, I have no idea, but if it helps, I've got a C210 FSM (Factory Service Manual) and I could scan the Wiring Diagram if it makes it any easier?

[g72s20]

I suspect Mike is on the right track....But you will need wiring diagrams of the C110 and whatever the donor loom came from. It sounds like a difference in sequencing during the keying of ignition(Gawd! sounds like something from "APOLLO 13") . Do you have the ignition and lock from the donor? It's just a guess but you may be up against a difference in what gets connected to what as the key is turned. This to me explains the need for extra relays, remembering that (basically) a relay simply "relays" the switching of +battery or ground(-battery). Remember, it all runs on smoke....if you let the smoke out ...ya buggered :laugh:

Jim.

[khughes]

okay, this is what it says (my memory is useless):

"Are you sure", he said "that when the key is in the cranking position the ECU is still getting the ignition on 12 volt feed?" and he was right, the old skyline actually switches off the 'ignition on' source that i'd tapped into when the key is at the cranking position. with a temporary direct feed from the battery the engine started instantly"

so how could i get the ign on signal to activate this temporary 12v's to the ignition on during cranking?

when i get time i will scan the article and stick it on our site

[g72s20]

Sounds like they just patched around the loom path. They've identified the point that needs +12V and run a direct feed from the battery, a brave move in electronics unless you are sure of what you are doing!

Do you have a wiring diagram for the donor engine or loom?

You don't wanna let that smoke out...they run on smoke you know....

[khughes]

i have the ECU pinouts and that is it unfortunately

http://r31skylineclub.com/content/techinfo/rb20pinnoutnics.jpg

i wonder if the key switch itself could be modified to supply the 12v at cranking? (i have to admit, i have no idea how the key switch would be set up, what would normally be active on the c110 during cranking?)

i promise that i will keep the S2000 starter button option as the very LAST resort

[g72s20]

I can put you in contact with Ray Ferguson (Prince) builder of NA RB20 into his kpgc110 body. He did convert to dizzy ignition though. I'm bettin' he'll have wiring diagrams?

I can't see it being too hard to set up though..as long as you can get the cct diagram of the donor , and drive a multimeter, you'll be able pick up the battery or ground from the C110 key ignition action, as required by the ecu of the new motor and then run it via relays as required..I don't know if it really is that easy in this case. For me it's usually a case of try it and see!!

That pinout diagram is a good start, but I would still like to see what the ignition switch is doing ("ON" and "START"positions) in the donor car.

[440k]

I'd say the easiest way to get a clean 12V signal while cranking is to take a feed off the solenoid switch circuit, (which should be one of the outputs from your ignition switch - that goes straight to your starter solenoid) and use that to trigger a relay (that way you can't get backfeed of current into the starter solenoid from your ignition circuit). Not sure if that's how it's done, but to a dumb mechanical person like me, it makes sense.

The starter in my 240K (Leyland 4.4V8 engine) has a second terminal on the solenoid, that provides 12V power while cranking. This attaches directly to the coil (bypassing the ballast resistor on the coil).

The reason for all this nonsense is that if you feed 12V through most ignition coils, it fries them. They're designed to operate on 5-6V, so the power all runs through a ballast resistor. However, when you're cranking the engine, you want as much power as possible (and the starter draws a lot of current, which may rob other circuits). To achieve this, a 12V signal is fed directly into the ignition coil, only during engine cranking. This is the feed you want to trace, and it should already exist in the 240K.

Hope this all makes sense.

Looking at the circuit pinouts, I'd guess that you want to feed the 12V into pin 36. That's my interpretation fo the diagram, although I accept no liability if your ECU (or entire car) ends up as a smouldering heap of black goo as a result of taking my advice :cheeky:

[khughes]

thanks guys,

i will have to try and look at all the manuals i have and try to make a little more sense out of what you have said

i still am yet to source a starter for the motor, but most likely it will be an R32 item, which i have diagrams for.. will look them up now!

Kent

[440k]

I had a look at the wiring diagram in my 1600 manual. I'd guess there's a fair chance that the 240k ignition switch is the same wiring setup (altho stranger things have heppened). It has 2 outputs that supply 12V upon cranking. Terminal 2 supplies the starter solenoid, and terminal 5 supplies a 12V feed for the ignition circuit, bypassing the ballast resistor.

What's terminal 2 and terminal 5 I hear you ask? Buggeref if I know, I'm afraid. Best to take to the switch with a multimeter or test light, and see which terminals are live when the key is in the "start" position. The wires on these terminals should match the colour of a wire going to the coil (to the same terminal as the ballast resistor goes to). That's the wire you'll want to connect to the ECU.

Again, this is for a Datsun 1600, which I'm pretty sure would be very similar to the 240k. If one of our 240k owners with a manual could care to confirm this...

Cheers

Peter

[240K&Beyond]

Kent,

There is probably an easier way to do this, get a big diode (At least 3 to 4 Amps) and connect it from the "iginition/Start" terminal to the "run" terminal. The Cathode end of the diode goes to the "run" terminal. (Thats the end with the "band" around it.)

This will supply volts from the "iginition/start" side whilest starting. Once you let go of the key, you will automatically continue suppling volts from the "run" position.

Note:

1) If you get the diode around the wrong way, it would be pretty easy to tell as your starter would continuously be cranking.

2) You may need to measure how much current is going thru the "run" position wire in order to gauge what size diode you need.

Good Luck.