<ANSWER JZGTE igniter = dumb> JZ-GTE igniter / IGt

[Mos]

Firstly, you only need a 3V dry cell to switch the transistors... So maybe 5V is just ensuring the signal voltage is always high enough to trigger...

The transistors turn on based on current flow - the voltage just ensures an appropriate amount of current flows into the base of the transistor (internal resistors will limit this current to a safe level).

Secondly, when you apply the voltage the igniter, it "momentarily" (read:dwell?) earths the 12V supply to the respective coil. It doesnt matter how long you hold the 3V there, the coil is only earthed for the same constant "moment".
Does this make it a constant dwell system?

This does not sound consistent with the idea of just a power transistor - the negative (rather than the 12V supply) of the coil should be pulled low for the same duration as the signal. There should be no "moment" - it would imply the ignitor controls dwell in some way and has additional circuitry inside the ignitor. Can you scan/provide the relevant pages out of the TSRM?

Mos.

[mic*]

http://www.supra.co.nz/87tsrm/Ignition/ignition17.htm

Page IG-17

What i meant was the 12V supply is earthed THROUGH the coil, so it IS the negative side of the coil which is pulled low (earthed) by the transistor - momentarily

The thing is i totally agree with everything you've said, but check out the TSRM...

Im curious enough that im gonna open up the spare 7M igniter ive got just to see whether there is some sort of capacitive discharge circuitry or something to create a set "moment"

EDIT: You'll also notice that coils A & B require voltage at what im assuming is the base of the power transistor which controls coil C, as well as their respective transistor bases, to fire... Makes me think that its more complex than three transistors inside???

[Mos]

Interesting. I'm thinking the term "mometarily" doesn't imply it controls dwell - would have to scope to learn more.
The power supply could be for protection diodes, but I guess it's possible there might be more circuitry in there.

Mos.

[thechuckster]

the extra electronics are probably there to allow the unit cope with a variable power source (think low voltage during cranking).


edit: this is just a wild guess, but the electronics also allow the unit to cope with coil ringing (flyback).

[The Witzl]

If i'm right... then Wilbo has just shown that the *JZ-GTE ignitors control dwell based on their input signal.

Note the third graph in this image below:




This graph would depict the IGt signal from the ECU to the ignitor. The length of time that the IGt signal from the ECU goes low directly represents the dwell time for the coil - ie. the ignitor just mimics that input signal and applies it to the coil, without any changes.

This varies to a "smart" ignitor, which will vary the dwell time of it's own accord.


Correct me if im wrong.

[wilbo666]

Yeah my research indicates that the *JZGTE igniter is dumb, and that dwell is controlled by the ECU via the IGt pulse width!

I suspect the Igniter may have other circuitry such as a 'lock up protect' mechanism, but I didn't look into it. The autoshop101 docs allude to what is in the igniter...(but then again it also says dwell control is in the igniter )

Cheers
Wilbo

[The Witzl]

Yeah my research indicates that the *JZGTE igniter is dumb, and that dwell is controlled by the ECU via the IGt pulse width!

I suspect the Igniter may have other circuitry such as a 'lock up protect' mechanism, but I didn't look into it. The autoshop101 docs allude to what is in the igniter...(but then again it also says dwell control is in the igniter )

Cheers
Wilbo

Would also be interesting to see if some of the other *modern* toyota ignitors are the same - ie. 4A-GE, 3S-FE, and other common jobbies you can find at wreckers with ease.

[wilbo666]

Would also be interesting to see if some of the other *modern* toyota ignitors are the same - ie. 4A-GE, 3S-FE, and other common jobbies you can find at wreckers with ease.

If you (or someone else) wants to swing it, I can have a look at it...

Acutally I think thechuckster has a few 3s ignitors that he might want to lend to this cause...

Cheers
Wilbo

[thechuckster]

i can bring a handful on Tuesday?

[Bowlsclubboy]

Wilbo, i'm purchasing my adaptronic tomorrow. I spoke to andy for 15mins or so and he decided i need 6x 'dumb' ignitors for a 1j. So thats what i'm getting.
Still need to chase a base map to make the car go though lol

[JP]

Kaizen Garage have done a 1J with adaptronic, they could possibly supply a basemap.

They also use ZZE corolla coil's for many of the adaptronic installs on different motors, 4a's, 3S, 1J etc

[wilbo666]

Kaizen Garage have done a 1J with adaptronic, they could possibly supply a basemap.

They also use ZZE corolla coil's for many of the adaptronic installs on different motors, 4a's, 3S, 1J etc

Yeah I should be able to get a base map off Tim, so I'll be doing that in the somewhat near future (when I get around to the aftermarket ECU )

Cheers
Wilbo

[Bowlsclubboy]

Hook me up if you can then

[wilbo666]

I still need to give ants a call (really should get around to that!), but I you could try PMing timottaway?

Cheers
Wilbo

[mic*]

I know the conversation was generally about the 1J igniter and it's dumbness. Here are a couple of (bad) internal pics of a 7M igniter i molested. Its certainly more than i expected...[IMG][/IMG]

- Correction: ONE pic, not even the good one... stoopid imageshack always seems to f up when i wana host something