xwarp

Tried to think of a catchy title while trying to decide if this was the right place to post this thread.....

I'm currently driving an '85 S15 with a '93 3.4 engine. Tranny is a 700r4. Throttle body is from a 4.3l, so it has bigger bores than the 2.8l throttle body.

I've currently got a 1988 S10 auto trans 1228062 ECM using the ACHT BIN file.

I did start with the 1228062 ECM but swapped to the 1227747 ECM by recommendation. I ran that ECM for a while with a modified ASDU BIN but it just never seemed to run quite right. Throttle seemed sluggish and timing seemed off.

While trying to learn more about the ECM and the parameters in the BIN and correct those issues I was having, I was finding parameters in the ASDU BIN that seemed like they weren't working for my application. Parameters such as Spark Latency for example, or, even parameters that would have involved values based on larger engines.

I've found that the 1228062 ACHT BIN, that while used in trucks with automatic transmissions only, the 3rd/4th gear Upper Limit/Lower Limit TCC lockup tables were all set to 100%. I'm not sure why. I also found quite a few of the 1228062 2.8 BIN's were the same. I also found 1228062 4.3 BIN's that did have varying percentage numbers.

Now, as I've gone along and have learned more, I've been thinking about going back to the 1227747 ECM, but the question keeps popping up that I can't seem to find the answer for in regards to using BIN files written for 90 degree engines with a 60 degree engine.

And so this brings the question, should I change to the 7747 and then apply the 60 degree parameters where needed, or, will that cause more issues than it's worth?

RBob

iTrader: (1)

The advantage of the '7747 is that the code is well known. So it is easy to edit and understand how things work. Ignore the 60*/90* differences, just tune it so that it runs right.

Note that setting the cylinder select value is important as it affects the final spark advance.

RBob.

xwarp

Thanks for the reply RBob.

One of the reasons I asked about 60/90 degree parameters was because as stated, one of the questions was about the Spark Latency Tables.

There is a thread where you discuss this parameter and being that my engine is using the smaller distributor is why I am thinking I was having timing issues in my 1st attempt to use the 7747.