Xephius

So I am doing my reading on the boards here. I have read the 3 primers on ECU tuning, and numerous posts. I ordered my hardware, extra chips, and have a laptop to do the work on.
I _think_ I am going to use TunerPro, but may buy TunerCats, I am not sure yet. I think I need more hands on. I have looked at the .bin library on:
ftp://ftp.diy-efi.org/pub/gmecm/
I have no idea what each files corresponds to, is there a reference file that says what each bin is used on? Knowing X file is stock, and X file is a "performance" bin would be a huge help.

I am working on a 95 G20 TBI 350 right now. I found a post where Fast posted up a fuel/spark snip to suggest a better map. I am trying to get to a map that is more efficient (MPG) on a stock motor for now. As I understand the spark is retarded and the fuel map is generous to a point of waste. I have read the relationship between spark advance and fuel map, so I didn't want to just start advancing spark arbitrarily without having a more "referenced" start point.

Anyway, right now I am just looking and comparing bin files, trying to understand the relationship between different settings, and getting familair with the software. I hope that I will start actual programing this weekend.

BTW, does anyone know where the ECU is on a G20?!? I looked under the seat, under the dash and under the hood. Unless it is hidden above the steering column, or way up in the dash, I can't find it. I did locate the airbag/vehicle control box in the left kick panel, but no ECU....

I hope that I have not broken any of the board etiquette rules here, I am trying. Thanks all.

X

Grim Reaper

I cannot speak specifically about your bin as I have not worked with it. But I have worked with a number of other bins, including some trucks. While most of the time, I am tuning for power, there are somethings you can do for fuel economy.

1) Try and find out if there is a Highway/Lean Mode. Many bins do have it, though its disabled. Do a search on Highway Mode and some reading in the actual Guide - I believe their is now a chapter on Highway/Lean Mode (but I'm not positive). I did a lot of posts a few years ago on that subject, so check them out.

2) If the bin does not have a Highway/Lean Mode, you can accompilsh the same thing. Force the ECM into Open Loop and then tune the lower Map values to go lean (15-16:1). The lower Map readings are usually when you are just cruising, so the leaner mixture will help.

3) With a Lean Mixture, you need to add more spark (but be careful). I have gone as high as 47* with a real lean mixture. The higher spark advance reduces the "throttle spounginess" you'll notice. I have found the leaner the mixture, the spoungier the throttle.

4) There is a "balance/threshold" betwen the lean mixture, high spark advance and the percentage of throttle needed while cruising. I have found that when I have gone leaner than 17:1, that either I started to need a very large spark advance where "crossfiring" to the "back terminal on the cap" could occur OR the throttle position was so large that I was getting WORST fuel economy. You'll need to play with this.

5) Keep your EGR operating longer. As you near WOT, the EGR will disable on most calibrations. Keep it operating longer.

6) Play with locking your TCC quicker, at lower speeds/rpms and staying locked longer. If you have an electronic tranny, make it go into a higher gear quicker. Again, you MUST play with these.

These are just some of the items you can look to play with (not knowing the parameters of your specific bin...but items that seem to exist in most calibrations that should help get you better fuel economy.

Xephius

Grim,

Thanks for the heads up on the highway mode, I will start searching the threads. I am sure I will be back with more questions.

BTW, the last 3 digits of my black LT1 van are really 666!

Thanks,
X
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665 = The Neighbor of the Beast
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Grim Reaper

There are no coincidences.