MPGuino release one workspace

[cmags]

Yea, I'm running on a very minimal budget at the moment so I don't think i'm going to pick up a second 'duino, but i'll try using cleaner power (pull from 12 and 5 for 'duino and LCD on an ATX molex) and see if it still occurs. Right now I've got my 16V laptop power brick pluged into the 'duino since the 7805 can take up to ~35V, but maybe it doesn't like it. I'll try hooking up the inputs too.

On a side note, since I'm closing in on the connect-to-car point, do we have any good sources yet on how to determine the car-specific parameters in the code? Specifically info on the injectors? (This question keeps getting ignored in my posts)

[awillard69]

To directly address your question, no, I do not know of any progress for automotive specific details. I think the intent was that each individual "tester" would provide their observations and gatherings and build the knowledge that way. More of a shared knowledge approach. If you are the only one with a model of vehicle, then you would have to do most of the legwork. But, don't quote me on that, maybe others can provide guidance.

Have you Google'd for your data? Wiki searches? Checked the library/bookstore for repair manuals?

As far as your connect-to-car status, if you are not confident in the device, putting it into the car will likely add to the frustration, especially if you suspect something is not quite right.

If you do get it hooked up, then some trial and error (hopefully not much of the latter) should get you close and allow you to reach stable settings.

[cmags]

Ok, I must not have been clear. I have the resources available, I'm just not sure what I'm looking for. Are the vssPulsesPerMile, microSecondsPerGallon, and injectorSettleTime properties of the speedo and fuel injectors that would be listed on spec sheets for those parts? I have the full service manual, and my car is very tuner friendly and the forums out there have very knowledgable people so I can get questions answered if I know what to ask.

[dcb]

Nobody to date has come up with a specific formula to provide the initial guesses for vss and fuel based on a vehicle model. It is no small task.

I suggest to start by getting vss close (drive at 50, fudge vsstics/mile till the indicated speed looks about right). Your car is *probably* 8204 vss tics/mile, but let us know if it isn't, and do tell which car it is. If the guino mph is slow then reduce the vssTicsPerMile by the percentage it is slow.

Once you have the vss in the ballpark, take a guess at what your mpg should be at 50mph. Then drive 50mph and fudge the microSecondsPerGallon parameter (bigger means more mpg) till the mpg looks about right.

Eventually we should get to a point where you can calibrate it at fillup time if someone doesn't dial in the injector formula in the mean time for all cars.

[awillard69]

Oh, now I see.

I would check what the Vehicle Speed Sensor outputs, how many pulses per mile. That is likely used by the speedo, cruise, ABS, etc.

As for the injector data, I'm still quite a bit vague. But, something in the injector volume or duration should help. You may need to find out what type/model of injectors you have and investigate that particular part.

Make a best "guess" as a starting point, and move from there as you refine.

[MilesPerTank]

Please point out the obvious flaw in my reasoning.

Injector size 180 CC. These are rated per minute right?

180CC = 0.0475509694 US gallons

So (1 / 0.0475509694 ) = 21 minutes

21minutes * 60 = 1260 seconds

1260S = 1260000000 uS

That is much larger than the default value for the late 90's saturn maybe?? and my current MPG reading is too high which makes me think I need a lower number.

Please point out the error here.

[dcb]

Well, how many injectors are there? Do they all fire at the same time? Is the injector actually running at max pressure drop?

About how far off do yo uthin the mpg is?

And please try and include the vehicle in question.

[MilesPerTank]

4 injectors.

So you're telling me the obvious error is i need to divide 1260000000 uS by 4?

What does #define numberOfInjectors do?


1992 Honda Civic CX (under my name). I'm not wiring this thing into my sportscar until its 100% tested.

[dcb]

I don't think it is obvious. I'm still trying to figure it out myself numberOfInjectors doesn't do anything yet because some cars fire all the injectors at once, some one at a time, and some in banks and without a database of what models do what, it is a challenging question to pose to just anyone. And there are undoubtedly other variables involved.

[MilesPerTank]

What equation have you used for your own injector size to uS per gallon calculations?

Are you really just randomly adjusting it to "look right"?