Re: 7747 tuning again

[WEG1192@aol.com]

In a message dated 09/24/2000 6:50:23 PM Eastern Daylight Time, 
RRauscher@nni.com writes:

<< The VE tables: I'll use straight decimal numbers here. The max VE value
 is 255 (a byte). Each table has a lookup done, with the results of the two
 lookups added together. This value can not exceed 255 (that's 100%).
 
 If one table has 255, and the other has 30, the result is 285, which can
 not be stored in a byte. The software checks for this condition, and if true,
 will set the VE to 255 (100%).
 
 If one table has 155, and the other has 30, the result is 185, which can
 be stored in a byte. The end VE value will be 185 (72%).
  >>

Bob,

If this is true, I ran out of table a long time ago. I had my adder table set 
at 80%, which becomes 204 (decimal hex), which leaves only (255-204=51; 
51/255=20%) 20% max in the main fuel table. No wonder there was no change for 
the last 10 runs.
Ok, so now I am back to basics I guess. Check fuel pressure under load first, 
pull injectors and make sure there is no dirt stopping them up although I 
just rebuilt the TBI, and try new injectors. Other than these steps, I don't 
know what else to do.

I do have another question about my scantool though. I can't get it to show 
injector pulsewidth, and a lot of other things on the 7747 ECM, but on my 
7730 ECM, it shows much more info. I just attributed this to the 160 baud 
rate of the 7747. But now I'm wondering if I bought a POS scantool. Its an 
Actron III with a GM cartridge. Anyone know whether these scan tools are any 
good?
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