MPGuino 1991 AUTOMATIC
 

I can't find anything about hooking this to an Auto trans car (1991 geo metro 1.0), I'm quite sure I have the pos, grnd and injector connections correct but the VSS is different than the manual cars. My car has a separate VSS in the transmission with 2 wires going to it I tried both of them and the first one didn't seem to do anything and the second one did once the speed was brought up (on jack stands for testing).

I know my speedometer is off due to the 13" tire/wheel upgrade (I calculated 8.3333% difference). I adjusted the VSS pulses per mile to 7524 from 8208 but now that I think about it this probably isn't right but I didn't want to start with a value that I know is wrong.

How much of an adjustment does this parameter take for a change like I have?

I didn't see (on the wiki or here) a way to get the MPGuino to display the VSS pulse count either or I could use that? if this is possible how is it done?

I get no instantaneous MPG reading until I get up to about 40MPH and then if I accelerate long enough the reading drops until it gets all the way down to zero and stays there until I lift completely off the accelerator-then it pops back up to 999- any ideas why it would do this? (I know 999 means coasting in gear already)

Dunno if this thread will help or not with the vss. But you want the one in the speedo, not the one from the trans I think (different signal strengths).
http://ecomodder.com/forum/showthrea...tml#post108671

^89 metro w/auto

OK I found the yellow/green wire under the dash on the drivers side above the fuse block ( the ECU is right there too). That made everything work much better and I was able to get a rough speed calibration for my car of 8100 pulses ( I went 50 MPH on the speedo and tried to get MPGuino to indicate 54.16 for the 8.333% difference) close enough for now.

It did freeze up on me once and there is one part on the back that I noticed gets a little warm is this normal or might I still have some connection problem?

So, from here, if I understand this right, once I get actual mileage from the next tank I start adjusting the injector input until I can get actual and MPGuino mileage to match right?

Here is the calibration page, it should spell it out, might want to be sure all connections are solid first and I would just leave it on the custom screen while driving to reduce the possibility of freeze in mid calibration.

Mpguino calibration - EcoModder

Thanks, don't know how I missed that page with all the time I've been looking at stuff for this- that's just what I was looking for.

good deal :)

The unit was working good today but it froze about 5 miles from home.

What causes it to freeze and is there a way to stop it from happening?

What is the best course of action to get it working again without wiping out the memory?

There is a part (op-amp I think?) in the picture below that gets too hot to touch for more than 1 second- is this normal or a sign of a problem?

http://ecomodder.com/forum/member-ro...188-guino2.jpg

that is the voltage regulator, it can get warm. I don't have a pat answer on the freezing, can you describe the conditions when it happened?

I would turn the brightness down (with the middle button) to like 1, and that should keep the regulator happier anyway.

I keep the brightness set at one already.

Today it happened (I think) right after I hit a good size bump in the road in a construction zone (the 40 psi in the tires makes bumps feel a little worse than they really are).

So disconnect/ reconnect the power the only way to get it going again?

I finally got around to the last resort yesterday - hooking the unit directly to the battery, and it looks like that has solved all the issues I was having. It has worked 2 days now and about 65 miles which is a new record for me.

It was so bad last week I just unplugged it for about 4 days because it would freeze and/or reset itself almost continuously...I was starting to think something was wrong with it.