Tuning a crate 350 H.O.

[rokcrawlin85]

We're all broke now-a-days it seems. I was poor yesterday, i'm poor today, i'll be poor tomorrow. Oak Creek drive on 89 is a beautiful drive!! Love driving that way up to Flagstaff.

[EagleMark]

Oak Creek drive on 89 is a beautiful drive!! Love driving that way up to Flagstaff.

OK we have to stop, I'm getting depressed...

[rokcrawlin85]

deal. get back on subject of tuning. when you were saying earlier about the 7747 being off by one ..... something, i forget now, but what do you mean by that? what's off compared to the 8747?

edit: byte word. that's what it was

[EagleMark]

It was the ADX file. $4F and $42 will work on each other.

NOTE: THIS DATA STREAM IS ALMOST IDENTICAL TO DATA STREAM A33 -WITH THE EXECEPTION TO BYTE 1 BIT 6 DEFINITION.

Which is $4F = 6 1ST TIME IDLE FLAG 0 = FIRST TIME
Which $42 is = 6 HIGH BATTERY VOLTAGE

So I just copied $42 adx and changed that byte... to make $4F adx

[rokcrawlin85]

there's some extremely smart people out there to understand and change that stuff around. nice work to everyone that helps us, no so smart, folk out

[EagleMark]

Yeah really! We'd be screwed if it were up to me!

I just got involved on the ADX files while Robert WENT ON VACATION without teaching me first!!! Luckily he left behind enough for me to learn and reverse engineer. So if I can keep up on these he can put real talent to good use!

[rokcrawlin85]

ok, so i did a 7747 stock 5.7 truck bin burn. pulled my old chip out, put in the newly burned chip, and instant flashing CEL. Limp mode from the first start up, i guess there's other things that need to be done to get a 7747 bin to run properly in a 8747 ecm.

[EagleMark]

Sounds more like a bad burn or wrong offset or chip leg bent or install backwards... did you read the other thread? Pretty sure he used a 7747 bin and worked...
http://www.gearhead-efi.com/Fuel-Inj...o-1227477-swap

[rokcrawlin85]

i have read that one over and over i was thinking it would be pretty straight forward after reading it. i may have an issue like you posted with the chip. on that other thread, did he just run a 7747 bin in a 8747 ECM, the way it's writen it sounds like he used just the wires and connecters from the 8747 and just plugged them into a 7747 ECM, not just burning a 7747 bin into a 8747 ECM... that make any sense? i'll have to take a better look at the chip and make sure it was seated right too. i think its time to order a few more chips from moates...

[EagleMark]

He is now using a 1227747 ECM just plugged in the 1228747 harness! But earlier IIRC he used a 7747 chip successfully as well. Jim_in_dorris had looked up wiring harness details for us and mentions specific changes as we did not have 1228747 Wiring Diagram.

If any one has a 1228747 Wiring diagram we need one!!!

[rokcrawlin85]

ok, well i will certainly try burning another chip. making sure my offsets and everything match up correctly

[1leg]

I switched from a 8747 to a 7747 with no wire changes direct swap. The only issue i have is with my temp sensor and O2, nothing to do with the 7747 ecm.

FYI- I did try running a 8747 stock bin with the mask ID set to AA, in the 7747, still got the blinking CEL.

Sorry it took so long to find this thread. i guess i was too busy, turning and burning.

[rokcrawlin85]

I switched from a 8747 to a 7747 with no wire changes direct swap. The only issue i have is with my temp sensor and O2, nothing to do with the 7747 ecm.

Sorry it took so long to find this thread. i guess i was too busy, turning and burning.

so did buring a stock 7747 bin chip and placing it into the 8747 ECM never work right for you? You had to switch to the 7747 ECM before it would read the chip correctly?

FYI- I did try running a 8747 stock bin with the mask ID set to AA, in the 7747, still got the blinking CEL.

Isn't the mask id used for the 8747 $4F?

[1leg]

8747 computer stopped working all together, 7747 plugged in an.d ran with 7747 bin. I tried a 8747 bin in the 7747 just as test. It didn't work.

Using AA for a mask id, disables the checksum function, old jedi tuning trick I read some where.

[rokcrawlin85]

well that makes sense now. i'll have to try to burn another chip when i have time and test it out again in the 8747 to make sure it's the ECM to chip failure and not just the chip i burned.

disabling checksum does what exactly to an ECM?