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Question about TBI Flood Clear mode
11-02-2017, 05:00 PM
Post: #1
Question about TBI Flood Clear mode
Hi Fixkick!

I have been reading your explanation of the Flood Clear mode for TBI G16a engines.

(1) Does the ECU enter this mode any time that the TPS pin is > 4.0V (Ie. TPS Angle % > 75%)?

(2) What other parameters does the ECU require for it to be in this mode? RPM < 600 rpm to indicate starter is cranking?

(3) Does the ECU really cut fuel injection entirely, or does it do something equivalent, like narrow the pulse width so that it leans out fuel injections until the engine starts?

Thanks!
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11-02-2017, 09:17 PM (This post was last modified: 11-02-2017 09:43 PM by fixkick.)
Post: #2
RE: Question about TBI Flood Clear mode
8v or 16valve? year?
RTM
this only very briefly covered the FSM factory service manual.
sure cranking, there is an (I am) cranking now pin, on all ECUs here. connected to the start/crank lug of the IGN, switch. 8v is pin B11 (blk-yell)
http://www.fixkick.com/ECU/8v-tbi-schematic91to95.jpg
seems cuts fuel 100% why not? be easy to see with a scope.
unflood mode. (keep in mind wot is not calibrated, only the idle switch is. so wot can be 3.4v to 4.75vdc or as high as 5.25vdc but the software sets this only
Firmware, in the CPU.(ECU) 75% is a good guess, as any. my guess is over 3.4vdc as the book shows on 8valve, page below pin a21
Wide open throttle. i'd guess 4v or more, TP pin. I dont think the book tells this. only that it is WOT, crank and injectors stop for clear flood mode.
pin A21 is stated here,
http://www.fixkick.com/ECU/ecu-8v-sig-list/e76.jpg

not sure if it monitors RPM, as cranking is 200-300 rpm, about.
but may?, when it sees, over 600 it know engine started, as spark is for sure there. not sure. not me. and not easy to test this.
we now that this works push start (or by gravity) it know engine started, regardless of any crank singles. the 600 rule.
my guess an internal hidden firmware (Running flag)

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11-03-2017, 08:48 AM
Post: #3
RE: Question about TBI Flood Clear mode
(11-02-2017 09:17 PM)fixkick Wrote:  8v or 16valve? year?
RTM
this only very briefly covered the FSM factory service manual.
sure cranking, there is an (I am) cranking now pin, on all ECUs here. connected to the start/crank lug of the IGN, switch. 8v is pin B11 (blk-yell)
http://www.fixkick.com/ECU/8v-tbi-schematic91to95.jpg
seems cuts fuel 100% why not? be easy to see with a scope.
unflood mode. (keep in mind wot is not calibrated, only the idle switch is. so wot can be 3.4v to 4.75vdc or as high as 5.25vdc but the software sets this only
Firmware, in the CPU.(ECU) 75% is a good guess, as any. my guess is over 3.4vdc as the book shows on 8valve, page below pin a21
Wide open throttle. i'd guess 4v or more, TP pin. I dont think the book tells this. only that it is WOT, crank and injectors stop for clear flood mode.
pin A21 is stated here,
http://www.fixkick.com/ECU/ecu-8v-sig-list/e76.jpg

not sure if it monitors RPM, as cranking is 200-300 rpm, about.
but may?, when it sees, over 600 it know engine started, as spark is for sure there. not sure. not me. and not easy to test this.
we now that this works push start (or by gravity) it know engine started, regardless of any crank singles. the 600 rule.
my guess an internal hidden firmware (Running flag)

Quote:seems cuts fuel 100% why not? be easy to see with a scope.

I have a pocket Nano oscilloscope but it can only handle up to 10V X 10 using a 10X attenuator probe. Would that represent enough Y range to measure the Fuel injection pulse waveforms? Should the probes be connected to the red and yellow fuel injector pins or connected at the ECU pin side?

And thanks for these diagrams. Big Grin The vehicle being examined is a 91 G16A 8V US FED spec.
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11-03-2017, 09:40 AM (This post was last modified: 11-03-2017 09:50 AM by fixkick.)
Post: #4
RE: Question about TBI Flood Clear mode
10vdc scopes are only good for 5vdc logic, never for a car, , but they do sell 100:1 probes dirt cheap on ebay,
the red wire has its own pulse driver
the yellow has its own too, and are not the same.
the scope signals can be seen on any scopy 1960 to now, but not on toy 5vdc scopes easy, the cheap scopes blow up at drop of the hat. super easy. in fact.
cars can and do have 40volt noise spikes, called load dumps one is AC clutch engaged/disengaged. or starter noise, and any relay pulling in. and more. even fuel pump noise.


see drawing 2 here, this is what is there, inside, no lies.

http://www.fixkick.com/INJECTORS/the-pulses-matter.html

uP means micro P or processor in this case its the CPU port expander that runs the injector driver transistors
.


see all 3 scope views real? there.?
B8
B17
and transverse, across both.
any scope that can resolve 3mS signals, even a relic 1MHz scope works . ( only no toy scopes ) but if luck a 100:1 probe can work if it to see 15v pulses, (alternator voltage sets the max value)
the cheap scopes also have no DC amp to see the 0.15v reduced signals well, as in typical of cheap china scopes. they do make better scopes,
100v rated or 400, v. like real USA scopes have. made here.

one trick is to this inductively.
wrap 10 turns of fine wire around the red injector wire (this forms a Faraday magnetic air core transformer , easy)
then connect scope to that pair, now you read injection current. 15amps strong it is or 1ohm and 15v, I =E/R then do same on other wire, , yellow.

that is all i know for tricks , I have boxes full of scope probes of many kind ,current and voltage and even one for spark.
my guess is this cheap scope and has a 2:1 voltage divider to uP , ADC, input and super easy to blow up. in most cases. ($3 in parts there)

one advantage it (toy scope) does have is battery power and no references to ground, this can save it.. from damage. (but not transverse readings too high)
if no caring risk do the 10:1 probe and see 15v at 1.5v pulse, but there is back EMP signals there, from the injector coil see it in yellow wire scope view
it goes over 40v back EMF spikes this is aka inductive kick back, more Faraday magic and mr Tesla.
it may go higher that kick. i forgot to measure more carefully, (lazy me with my 600v rated tools)


good luck hope it works !!!

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