Rbob got me lookin at the PE enable at VDC of tps table because the rpm scaling was wrong on most ecu's. I broke out my 747 hack and went for a look see and realized that for one he is right and two the conversion is all messed up. 747mine. uses a multiplyer of 2 to get some big numbers like 204, 280, 128 and such. I started messing around with some factors and came up with this

say your table looks like this in hex

rpm hex
3200 66
2800 66
2400 80
2000 80
1600 8C
1200 9b
800 9B
400 40
0 40

then divide that table by 150 you get

rpm Volts
3200 1.47
2800 1.47
2400 1.17
2000 1.17
1600 1.07
1200 .97
800 .97
400 2.34
0 2.34

Does this look right? It makes sense to me except for the dip at 800 and 1200. I'm not real sure why it does that.

I think I might have just gotten the whole idea of this ecu thing. Or at least be able to actually make one or edit one.

 

The TPS vs PE enable table is in TPS%. The L0049 TPS variable is a percentage of TPS from the idle set point times a gain term.

So, in the end the TPS term for the above table is TPS% = N / 2.55

{and you have the RPM scaling all wrong still }

RBob.

 

ohh thanks sorry thought I actually found somthin, but this stuff is actually starting to make sense now. Thanks alot you have been a life saver over the last week

 

Actually you did find something. The conversion didn't make sense to you and you brought it up. The kicker is that the hac shows the TPS thresholds as a voltage. When in reality it is in percent.

Some folks wondered why I was spending so much time with my head buried in a hard copy of the hac. Like you, I too was going a little nutty when things didn't work out like they were supposed to.

Sometimes it can be difficult to follow the code and be sure of accuracy (such as the RPM scaling for those tables) that I resort to the ECM bench. I spent a few minutes last night to verify the RPM scaling. Then while I was there I turned down the voltage to the ECM until it was 4.75 volts. Do you know that the ECM kept running! I was a tad surprised. I thought for sure that it would have kicked into the backup fuel mode, but it didn't.

RBob.