How to simulate correct IGf signal?

[jezza323]

For reasons outside my control, to keep my CDI unit working i need to simulate a correct IGf signal, because the ignitor is no longer firing the coil there is no way for the IGf signal to be generated correctly.

Does anyone have any ideas how i can do this? Obvious way is to modify the ignitor input signal and return that...

check out the pic for more info

[Hen]

I'd be interested in this too.

One simple idea that springs to mind is to find an ignitor and feed it IGt, then take IGf out of it. Not sure if this will work as IGf may not be "good" unless a coil is attached to the ignitor output.

Hen

[jezza323]

the ignitor still fires, but because it is only firing the CDI and not a coil no IGf signal is generated...

[thechuckster]

can put an igniter between the ECU and CDI unit to provide the IGf signal?

Or is the CDI unit only able to accept a 5v logic signal instead of a 12V (dwell controlled) signal?

guess: you're running a stock ECU and it is refusing to continue proving spark triggers without the IGf signal?

[jezza323]

correct guess chuckster, however, the ignitor IS wired between the ECU and the CDI

the connect the CDI you simply snip the wires running from the ignitor to the coil, and the ignitor sides go to CDI input, and coil sides to CDI output.

however, toyotas have the IGf signal, which the ignitor no longer produces as it is no longer firing the coil, but yes it is still in use.

[JP]

Do you have an IGt signal going out?

When wiring an emanage to a toyota with the old style DLI system (7mgte, 4agze), you have to cut the IGf signal from the ignitor back to the ECU, due to this you have to fake the IGf signal so the ECU doesn't go into limp mode. In that application you use a simple circuit comprised of a transistor and resistor to generate the IGf response from each IGt pulse.

I'll see if I can host the guide with the circuit diagram for the emanage setup somewhere

edit: here you go http://users.tpg.com.au/adsl0uxv/IGt_to_IGf_circuit.pdf

I've used this circuit on a 7mgte and 4agze running emanges with success.

[sideshow]

just did some testing the other day with a 4ag with faulty ignitor

if there is no igf the injectors pulse twice then stop

so what i di it connect one injector puls esignal ot the igf signal that goes to the ecu

this kept the injectors pulsing

so u could try that

[jezza323]

awesome, i will give those ideas a go

ill give the emanage job a go first (cheers JP)

here is hoping that it will work!

[jezza323]

just a follow up to this

did the transistor and resistor method suggested by JP, it worked a charm, first go. think it cost me a total of about $1.40 as well

[JP]

excellent to hear! It's a handy little circuit.