So I'm looking at my TP log file and wondering why does the BPW decrease under accereration.

Example, at idle, 800rpm, about 35kpa, BPW is around 0.65ms. Under acceleration, 2000rpm, ~80kpa, BPW is around 0.17ms. Is this not as straightforward as it seems? There has to be fuel added somewhere thats not shown, but then again, why does the base decrease?

 

If you're using a vacuum adjusted fuel pressure regulator that where the difference is. As you lose vacuum the fuel pressure goes up, so the ECM doesn't "use" as much PW.

 

Not with port injection!!!!!


PW will follow VE and be highest where the VE is highest.
Also as rpm increases, the frequency of the injectors firing goes up.

 

The ammount of air per cylinder is what drives the pulsewidth. This is based on the VE, MAP, and displacement. Those numbers seem off. Waht size injectors does the car have? How are you deriving the PW's? From a datalog? At 80 kPa, you should have a higher PW then at idle. Your VE will likely be higher, and the engine is under load.

 

That's exactly how I thought it should be, higher VE higher BPW. I get BPW from TunerPro datalog. I can copy some of it in if you'd like to see what I mean. And no, my VE is not off that badly (that would make it more of an inverse VE according to what I seem to see).

 

My guess is that the ALDL definition is messed up and is not calculating the PW properly. I think maybe the reported numbers should be inverted since 1/.65=1.54 which sounds right for an idle PW and 1/.17=5.88 which sounds right for a PW @ 80kPa MAP and 2000 RPM. What is the conversion equation set to for BPW in the ,ads file?

 

Operation: Divide [Factor/X]
Factor: 65.536
Offset: 0

 

There's the problem. If the operation could be "Divide [X/factor]", then it would work. Change the operation to "Multiply [X*Factor]" and change the Factor to 0.0152587890625 and it will work. HTH

 

Ya, so is this just something that has always been wrong in the ALDL definition file...and no one really cares about BPW enough to fix it?

Even the most recent definition for a '730 that comes with TP has this (its actually multiply X*Factor where factor is .015259), which is still the same as divide (Factor/X) where factor is 65.536.

Thanks
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Whoops realized Factor/X, not the inverse. I'm tired sorry, I'll switch it and see how she works. Thanks

 

That seemed to fix the problem, looks believable now, idle around 1ms and as rpm/map increases, so does BPW.

Thanks guys.