igf

[totta crolla]

Whilst l know (or thought l knew) what igf does l wondered if anyone knows what it actually monitors as a return to the ecu?
I'm chasing a 0° btdc timing issue on a Freedom ecu and when this happens the engine will not start.
The display shows 0° btdc in the ign timing log.
I did nothing but cleaned some fouled plugs and the timing is back to 18° btdc and the engine starts.
lt looks as if igf monitors the actual spark at the plug rather than assuming the signal has been sent so the plug must have fired. (which was my understanding)

Update..
some people will already know this but a little testing proved that fouled plugs in themselves may not be the only reason your 4age won't start.
It turns out that no igf return due to a lack of actual spark at the plug will cause a zero ignition command and also a zero injection command, this of course makes perfect sense but it's nice to know what's happening and this might be useful for someone sometime.

[Davegt27]

from Google

IGF (Ignition Confirmation Signal)
The ECM uses the IGF signal to confirm each ignition coil has fired after it sends an IGT pulse. The ECM supplies a 5V reference voltage on the IGF circuit shared by all coils. Each time a coil fires, its igniter pulls the IGF 5V reference voltage to ground.

[Davegt27]

I think you had been asking about the freedom ECU

https://page.auctions.yahoo.co.jp/jp/au ... 1086892262

maybe ask for a copy of the software

this might be even better, looks like windows version of the freedom ECU software

https://page.auctions.yahoo.co.jp/jp/au ... 1090870336

[jondee86]

I haven't really looked into this in any depth, but I believe that late model vehicles
with factory fitted "smart" coils can detect if a cylinder is misfiring. It probably does
this by monitoring the current drawn by the coil. And because the ECU knows the
order in which the coils are firing it can indicate which cylinder has a problem.

This is way beyond the ability of any factory 4AGE ECU. These simply monitor an
IGf generated when the ignition transistor switches the coil primary winding to
ground. There is no way that the ECU can know if there was an actual spark, only
that the 12V supply to the coil was interrupted. If there is no IGf received after a
certain number of IGt signals have been sent, the ECU will shut the engine down.

I have no way of knowing what the Freedom ECU can do, but given it was designed
to work with the 4AGE, I would it to have the same ability as factory 4AGE ECU's.

Cheers... jondee86

[Davegt27]

Moto P used a Freedom ECU on his AE86 build years ago
which is one reason they are so popular
the big problem its in Japanese