Corolla ECM Data
 

I was looking for just a pinout of my car's ECU (ECM as Toyota calls it), and stumbled across the PDF linked to in the 9thgencorolla forums.

Not only does it give me the pinout to find where I can tap in for my Guino, but also waveforms and voltages of fuel injector and vehicle speed signals.

Can anyone help me decipher this into Guino settings so I can maybe skip weeks of "dialing in"? Please? Pretty please with fuel savings on top? :turtle:

Subscribed. I have 4 9th generation corollas in the family and mine is an 8.5, which has the same ECM if I'm not mistaken. Don't want to lose the thread.

If my maths is correct, which I doubt (and can't compare live since it's not installed yet), the VSS goes something like:

20 msec/pulse @ 12 mph
12 mph = 5 minutes/mile
20 msec = 0.0003333 minutes
(5 minutes/mile) / (0.0003333 minutes/pulse) = 15000 pulses/mile?

Does that sound logical? Seems high compared to the values in the Guino wiki...

Trying to convert the fuel injector graph to usable data seems a bit more difficult. First, the graph states that the given conditions are "at idle." That could be anywhere from 800 RPM to 1,200 RPM. There's also no flowrate information for mgal/pulse that could be used to calculate how many pulses/gallon (which makes more sense to me than microseconds per gallon... how does that work anyway?)

Can anyone with better math skills than me chime in? Anyone have the teacher's manual ;)

It's not 20 msec/pulse, it's 20 msec/DIV....I think they mean per division on the graph. Going by that, the pulses appear to be approximately 25 msec long. Also, that time is probably time per pulse HIGH....not including time LOW. So, HIGH + LOW according to the graph seems to be.....more like 60 msec/cycle.

300 secs/mile @ 12 MPH......300,000 msec.......(300,000 msec/mi) / (60 msec/pulse cycle) = ~5000 pulses/mile...


Is that more in line?

Ah, see, that seems more likely. So my math was correct, my comprehension of graph data was wrong http://spidermouse.us/images/smilies/dunce.gif

I'm going to have to go through the Guino workspace thread... I still can't wrap my head around how microseconds per gallon works here...

*edit* - ok I get it, injectors are rated by lbs/hour which can then be converted to microseconds per gallon.

Do you have the Excel spreadsheet that does the conversion for you?

Which conversion? Also: there's a spreadsheet?

There's an Excel sheet to convert lbs/hr to usec/gal for you. It's linked to on the wiki page for the MPGuino.

OK, using the chart and the estimation from links in the wiki (I may call a Dealer parts dept this weekend to compare) we've got

VSS/mile @ ~ 5000
usec/gal @ ~ 266228338

I'm shooting to get tapped and mounted this weekend, so we'll see. (wow that sounds dirty...)

*edit* - following another link in the wiki, I find 4000 VSS/mile. Well, it'll be around one or the other so I'll know if it's 20% off. :)