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boost freak
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Discussion Starter · #1 ·
aight...in my quest to 2 step w/the eman, i am trying to figure out just how the ign sys worx. the heck does IgF do?!?! appears to be a signal integrity check to me.....but i can't find a clear answer. if you know, post! ;)
 

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boost freak
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Discussion Starter · #5 ·
eh. kinda. i can't take all the credit- a dude on the eman yahoogroup thought it up....i'm just putting a new twist on it.
 

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GOT BOOST?
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551 Posts
If you interupt the IGF the ECU will loose RPM count and stop pulsing the injectors. =)
Also there has to be no signal for more than 8 sec or somthing like that. You have to cut the IGT signal .... That would interupt the ignitor imidiately.
 

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boost freak
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Discussion Starter · #7 ·
not really. all of the IgTs are pulses to each coil, you'll have a hard time interrupting all 3. the philip long 2 step messes with the IgF, so i'd imagine we can do the same....realize we're talking microsecond interruptions...enough to make it cut spark, then spark again. we'll see if it worx!
 

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2/3 HP to the Paws
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The best way to go about a 2-step would be to run the three injector wires through a black box and cut the rate.

This is kind of how the Racelogic traction control works on the MkIV, and it does a great job.

Pulling IGF = engine dies.
 

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2/3 HP to the Paws
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drjonez said:
then how does the philip long one work?!?!?!
No idea, I'm a road racer. :D

From a design perspective, though, it would be best to cut rate on the injector pulses themselves.
 

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boost freak
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Discussion Starter · #11 ·
hmmmmmmmmmmmmm. just thought about it more, i don't think you want to be cutting fuel....that can go sour real quick....kinda like how the rev limiter/FCO doesn't cut fuel, just spark....
 

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2/3 HP to the Paws
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Not if you do it properly, which is the key issue either way.
 

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Registered
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Don't cut the fuel, even if you didn't end up getting lean cycles, you want the extra fuel to be burning in the exhaust (assuming you are 2 steping for spool and not just a lower revlimit). You can cut spark after the igniter too, there is one wire for each coil and one wire common to all three. I have a diagram somehwere of how the igniter signals work if you really want to go that route.

GLEN
 

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boost freak
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Discussion Starter · #14 ·
the problem with cutting the signal after the ignitor is hoping that the field breaks down fast enough.....

does anyone know how to get in touch w/philip long?
 

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wastegate hose is pulled
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4,586 Posts
I think you would want to interrupt IGt input to the ignitor. I think you might still have a problem with the TCCS going into "failsafe" mode if it does not see enough returns on IGf from the ignitor. It wants to save your catalytic converter!

ps- got the I/C thanks doc. :)
 

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GOT BOOST?
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drjonez said:
not really. all of the IgTs are pulses to each coil, you'll have a hard time interrupting all 3. the philip long 2 step messes with the IgF, so i'd imagine we can do the same....realize we're talking microsecond interruptions...enough to make it cut spark, then spark again. we'll see if it worx!
:rolleyes: :rolleyes: :rolleyes:

On the MK3 Turbo ignitor there is only one IGT signal wire. You have IGA and IGB which determine the coil sequencing.
Its called coil multy-plexing...
It works like this.

IGT is the timing advance and trigering even.

The IGA, IGB determines coil to be trigered.
IGA IGB
1 1 Coil one
1 0 Coil two
0 1 Coil three


It might not be the exact on off order but the principle is the same. More information is availiable at the Toyota study documents on line.

:eek: ;)
 

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boost freak
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Discussion Starter · #17 ·
ack. that's what i get for mixing my toyo ign sys info..... :p

oh well, i won't be testing for quite some time due to holiday events, etc....i'll prob try cutting IgT and IgF....

2J- is IgF the ignitor fire confirmation to the ECU on the MKIII?
 

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GOT BOOST?
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Yeah... It is emision safety... It tels the ECU that there was a spark and the ECU knows that the fuel was burned... If it doesnt see that signal it shuts the injectors off after so many consecutive missfires.
 
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