Re: 7747 tuning again

["Kevin R" <KEReyn@gte.net>]

Read thru and if it was listed I missed it, but do the BLMs show up in all
this?
Is there a way to read and then chart all the BLMs stored  in say a spread
sheet.
Would be less hassle than holding a 3 line scan tool when tuning and would
give a better view of " the whole picture" fuel wise.

Kevin R

> Hi Walt, I was starting to wonder if anyone was reading my posts <g>.
>
> Here's an introduction that I've put together. . .
>
> BobR.
>
> GM ECM Data Collection System, Lockers
>
> Robert Rauscher, 4/9/00
>
> General:
>
>     The Lockers system described in this article is for use on the
>     '747 ECM. It will work on some other ECMs without changes. Other
>     ECMs will require minor changes in the Lockers system.
>
>     The purpose of the ECM Lockers system is to collect ECM data and
>     vehicle data during the live operation of a fuel injected
>     automobile engine. This data is then evaluated 'after the fact'.
>     An evaluation program is used to analyze and display ECM
>     information directly related to the performance and tuning of
>     the engine and drivetrain.
>
>     This evaluation program is used after the data has been
>     collected. Drag runs, cruising, and driveability situations can
>     be collected and evaluated.
>
>
> The Hardware:
>
>     The data is collected from the ECM 'service port', which is
>     nothing more than the CPU bus. The collection hardware does not
>     interfere with the operation of the ECM, it is transparent to
>     it. This board simply plugs into the service port connector.
>
>     The data collection hardware has three sections:
>     A section to save the ECM data locally, a section to read that
>     store of data and transmit it, and a timing section. A RAM chip
>     and some mux's comprise the data storage section. A Microchip
>     PIC is used for the communications transmitter, while some
>     single-shot devices provide bus synchronization and timing.
>
>     The collection hardware is also powered from the service port.
>     This includes the serial interface which uses a MAX232 to
>     provide RS-232 signal levels.
>
>     The PIC has eight analog input ports available. A planned
>     enhancement is to add exhaust temperature monitoring with eight
>     thermocouples in the headers. This data would be collected and
>     transmitted along with the ECM data.
>
>
> The Data:
>
>     The data collected is the entire RAM area used by the ECM.
>
>     These 256 bytes of data contain information from all of the
>     sensors, scratch pad for calculation routines, stack area,
>     bit-mapped flags, and more.
>
>
> The Communications:
>
>     Data is collected by a laptop is to be analyzed later. A serial
>     receive program for the laptop is provided. A standard terminal
>     program can also be used for data collection. The program
>     provided has the additional functionality of timestamping and
>     point-marking the data stream.
>
>     Data packets are transmitted at two user selectable rates:
>
>     38.6Kb, 10 frames per second.  (153.6 KB/minute, 9.2 MB/hour).
>     57.6Kb, 15 frames per second.  (230.4 KB/minute, 13.8 MB/hour).
>
>     So, at the higher rate, you can gather every bit of the ECM's
>     RAM data fifteen times a second. The transmission rates are
>     limited by the laptop that is being used. The above rates were
>     obtained with an old 386sx @ 16MHz. That was the best it could do.
>
>     Using a 486 @ <anything>, would easily obtain 115KB with 30
>     frames per second. Minor changes to the Lockers system are required
>     for the higher transmit rates.
>
>     The data is transmitted in packets of 260 bytes. Starting with
>     two sync bytes, 256 data bytes, ended with two checksum bytes.
>
>
> The Evaluation:
>
>     Once the data has been collected, it is available to be evaluated.
>     A PC-DOS program is provided that displays in tabular form, various
>     selected data information. The eval program converts the ECM data
>     into real world numbers: rpm, mph, drp cnt, map, tps, injector pulse
>     width, pump shot, o2 sensor, and more. The data values to be shown
>     are user selectable.
>
>     The evaluation program also calculates and displays acceleration
>     rates, and crankshaft torque. Fuel consumption calculations are
>     currently an in progress enhancement.
>
> --
>


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