I was doing a test of a backup ECM I had laying aroud. So I plugged in a 1988 Prom (AKXY) - 5.7L, auto, 3.27, fed emm, no VATS.

My current setup uses a 1987 prom (ABWN) - 5.7L auto, 3.27, fed emm.

They seemed the same, so I figured the results would be close, and perhaps the 1988 would have some "fixes" in it since it was a year or more newer.

The results were suprizing. The first road test felt very much the same. Lock up points were similar to the point I did not notice. Startup seemed better. Now the big difference. On a 0-60 test, the 1988 chip had so much advance in it, that the engine pinged! With my 1987 chip, nothing, notta, zilch! Could the advance curve be that much different?

After this test, I did another the next day and the engine did not ping as much, just a few between 1st and second, (unlike the rattle from before). So I am assuming the ECM is learning where the peak advance was (or I hope so ... someone jump in and correct me). This second test feels much stronger than the old prom.

Anyone compared a 1987 bin and a 1988 bin. Any big difference in the prom, specifically the spark? I have winbin and the 1987 image, but I don't have the 1988 image. If someone has a AKXY image, I would be greatful if you could send it to me!


Conclusion ... a 1988 prom may be a cheap upgrade for those running a 1987 version. Some people may just give away the stockers. That is where my 1988 came from.

Mark.

 

The "hot setup" is to run the 1989 ARAP bin and YES you MUST tone down the spark table.

It's not just the spark tables, but the MAF tables that tend to be the biggest differences from "eprom to eprom" for the same vehicle (sometimes even the same model year).

If you want max performance, look at eprom burning. Then you can do ANYTHING (well almost) but a lot more than just "fuel and spark". How about controlling your Knock Sensor? Or invoking Highway Mode to maximize your gas mileage.

If you are planning on modifying your motor, it is a good idea to learn eprom burning. It's far easier to begin when your engine is still basically stock AND you can get some impressive gains too. Then when you've learned the basics, you'll be able to do virtually any modification.

 

Yes PROM burning has been on my list for some time. Just have not bought the darn burner/reader yet. I have many bins, ecu's etc. Dabbled here and there.

Engine is far from stock and runs quite well on a stock prom (insert surprized looked from me).

I was really just shocked at the spark advance between two chips which should be similar.

Does the ECM remember where the knock was for the next time, or will it just keep knocking?

Mark.

 

Wait for the surprise on your face when you optimize the eprom. There is SO MUCH MORE you can do with spark advance and knock retard routines WITHIN the eprom.

 

Ok, now where do you find a nice quiet road to "test" all of these configurations?

Darn exhuast is so loud, and the 1-2 "bark" attracts a bit too much attention.

About the only reason I have not bought everything is the CDN dollar (you will sympathize). The $150 burner is like $300 by the time I see it. Plus add Tunercat for $69.95 + the $32 and $32b images.

I know, I know ... "shudaup and just buy it".

tightwadly,
Mark.

 

I can save you some money on Tunercat. Just convert to the the 1989 ARAP code and just get the $6E. Forget the $32 and $32B, they are old school.

As for testing, I use "dyno hills". BC has lots of them. It's not necessary to "open it up", in fact, that's the LAST THING I ever do. I start off by driving around doing data captures to see what my "fuel and knock" situation is. Then I will find a nice long hill (Kamloops have lots, like the Coquihalla Highway) and I accelerate (but avoid going into PE) in second gear and take it up to 5,600 rpm a half dozen time. This way I can capture the data

Once you get into eprom burning you learn where the RPM/Load ranges are that you want to tune. I use SD which, in all honesty, is easier to tune - just a little more "time consuming". But I just "drive around" to gather as much data a possible and then take "averages" of the BLM/INT values to derive correction figures.

Also, there are "tools" like VE Master that will do this 'automatically' while you drive. But I actually like to look at my data. Converting to SD is a lot simpler than most people think. From a tuning perspective, I much prefer to tune SD than MAF. I can SD systems "much closer" and have it remain consistent for different elevations and ambient air temp. SD is also "faster reacting". It's impossible to keep MAF consistent when the elevation changes or air temp changes, and MAF is slower to react.

 

I'd still like to compare to my $32b. I drive that now, so it is a good reference about what I don't like.

Old school ... some of us live our lifes in that old school. :-)

... Thanks for the comments.