Help with MPGuino please

[dcb]

The mpguino works on just about any fuel injected car (obd II included) since it just needs a fuel injector and speed sensor tap. It works on most any SG car and then some.

Advantages:
1. It has the potential to be very accurate, displays are to two decimal places and kept internally to three places. It's not ECU scan rate dependent, but measures injector pulse widths within 10 microseconds in general.

2. It is very inexpensive. 1/4 the cost of a sg in kit form. 1/8 the cost if you build one from scratch.

3. the big numbers display is pretty popular (like in my avatar).

4. It sends distance/consumption data out the serial port for logging (i.e. on a laptop).

5. It's open source, so adventurous types can do things like add analog meters or make fancy cruise control circuits or get a head start on adapting it to other engine types (i.e. various diesels ).

6. it is %60 the size of an SG in its smallest form, which is handy if you put it in front of your instruments.


There's probably a couple other selling points. Some things to keep in mind are that it does have 4 wires you have to hook up. Battery positive, ground, vss signal, and injector signal. It should be about as hard to install as an aftermarket tachometer, whereas the SG plugs right into the obd port. Also the SG has access to basically all the engine sensors via the cars computer. The guino has distance and fuel consumption and various permutations (i.e. mpg , gph, etc).

[americasfuture2k]

here is a question kind of relivent to this topic, what wire on the VSS does this need to connect to? i have a high and a low wire to choose from.

[wagonman76]

I would think the low one. Same as how you connect to the low side of an injector.

But I prefer to connect it to the speed signal wire from the speedometer head. Some cars like mine use a VSS buffer to clean up the signal from the VSS, making more defined pulses which is more stable for the mpguino.

[americasfuture2k]

mmk.

with my ECM swap, the VSS send the signal to the computer, then the computer has an optional 4000ppm out for the speedo, cruise, or the SCV on my headunit. the VSS sends out 4000ppm as well. is this the butter-zone signal?

[wagonman76]

Im not sure about the Aveo, but the Fiero should be just like my cars. The VSS sends 4000 cycles per mile to the ECM (or VSS buffer), but not really in pulses. It is more like a sine wave because the VSS is basically an electromagnet. Not really friendly for the mpguino to use. The ECM or buffer turns this swinging signal into discrete square wave pulses at 4000 PPM to operate the speedometer and cruise control. My mpguino works rock solid.

[americasfuture2k]

im staying simple on the aveo and not cutting into any wires since it still has 24000+/- miles on the warranty. thats getting a scangauge II

ok, i will tap into that extra speedo driver wire coming from the ECM.

[americasfuture2k]

im really anxious to get see this thing work, so i want to hook it up into my aveo. but i have no idea which wire would be what. but on the main side, in OBD 2, it has individual injector control at lower RPMs. so how would a mpguino be hooked up as far as the injectors go for an accurate reading?