3S Fueling issues...

[RAd28]

injectors were spiking to a maximum of ~6V before settling to an average max of ~2V... never saw 12V...

using a stop watch to measure the pulse, i have very fast reactions... okay okay, using a "picoscope" (brand name) that dad had left over from his dyno tuning days... we're basically just using it as a computerised oscilloscope with a few bonus features.

[thechuckster]

you'd be better off measuring current flow to get accurate injector opening times.

FPR vacuum source has to be post throttle. Without traipsing out to the shed to find my manuals, i think the ports on the throttle are for EGR and charcoal cannister vent?



is my engrish much bettered?

[RAd28]

i'm not sure what the picoscope measures, but it displays voltage against time, i'm sure you could display current v time if you wanted.

[wilbo666]

injectors were spiking to a maximum of ~6V before settling to an average max of ~2V... never saw 12V...

using a stop watch to measure the pulse, i have very fast reactions... okay okay, using a "picoscope" (brand name) that dad had left over from his dyno tuning days... we're basically just using it as a computerised oscilloscope with a few bonus features.

Well something isn't right there....it might be in your measurement setup or??

Post a picture of waveform...

Cheers
Wilbo

[oldcorollas]

Pico stuff is usually pretty good... i've used their ADC's for a few things

[RAd28]

yeah, i'm pretty sure it's ADC200....

wilbo - didn't save any info... we were also having trouble getting the datalogging stuff working too... didn't recognise the port on the PC...

i'm also interested in other ways to accuratly measure the pulse width, because i'm not 100% convinced that the picoscop was set up correctly either... *-) perhaps i'll just consult the manual....

[thechuckster]

Current control is the key to injector control - if you can't measure it inline treat is as logic device that goes to ground when on.

[RAd28]

Someone VERY kindly donated an ECU and we got a chance to plug it in this morning and the results were very pleasing.
Below is the waveform as requested, and you can see there that's it's probably still a little more open the it could be, but it's about 1/10th what it was with the old ecu. We also made a few other changes like checking the earths, and fuel reg points etc... but i really think it was the ECU... either way, problem is almost totally fixed...

we've gotta pull the injectors back out, because i discovered that #2 injector is leaking, it's sitting in it's hole quite loosely... no biggy, but more work then i want to be doing.



You'll notice how open is only -1.5ish volts.... the spike is a little over 4V, but it never gets anywhere near 12V

[wilbo666]

You still aren't measuring from the right spot on the injector then.

Measure at the ECU end of the injector

Should be 12V -> 0.6Vish

Cheers
Wilbo

[paulioq]

all 3sgte injectors gen 1 2 and 3 are low impediance on both mr2 and gt4. it will send 12v from ecu but there is injector resistor unit which is located on pasanger guard this could have also been your problem?(dunno just a thought) if you need an ecu i got a couple and am in brisbane am looking at a carlosainze ecu thats been on my desk and i got no plans for as i right this. glad to here you sorted it out there a fun engine to play with

[RAd28]

Wilbo - we were measuing the power at the ECU plug... so couldn't get much closer to the ecu...

Paulioq - no idea why it's not putting out 12V... probably an operator error... I'm not exactly what you'd call a seasoned mechanic... a Carlos Sainze ecu would certainly be interesting, but i'm sure it wouldn't do much good with out a car to match

[paulioq]

ecu just has hire ignition timing to get 230bhp and no factory fuel cut to 17psi look them up they work on all 3sgte gen 1 and 2 with afm after a quick ecu repin. dont need the car to run the ecu??? any way good luck

[wilbo666]

Wilbo - we were measuing the power at the ECU plug... so couldn't get much closer to the ecu...

Paulioq - no idea why it's not putting out 12V... probably an operator error...

What are you using as your ground?

There really should be 12V when the injectors are off

Cheers
Wilbo

[RAd28]

Paulioq - I understand you don't need the car to make it work... but it'd still be nice to have the car

Wilbo - Using an earth which went into the ECU on the same plug, not straight to chassis.