[urq] EFI + MAC-14 maxing ataround 5k RPM

Huw Powell audi at humanspeakers.com
Tue Oct 23 17:36:58 PDT 2007

> The pulse width measurement I gave was with no load.

Oh, wow.  Sorry, I misread it as theoretical, not measured.  That must 
be your trouble then, right?  Either "running out" of PW, or really 
overfuelling (both as others have mentioned).

>>I’m wondering if the pulse width setting on the injection system is not right and the
>>injectors are simply maxing out at RPM.  That seems like another possibility than
>>ignition.  I need to check this in my MS settings.  I did some math:
>>I have a Max pulsewidth of 11.9 msec that I see in the log.  
>>5500 rev/min|min/60sec|sec/1000ms|=.0917rev/ms  -> 10.9ms/rev @ 5500 RPM or roughly
>>Roughly @6000RPM is 10ms/rev
>>So if my max pw is 11.9 but if a rev. happens in only 11 ms then the injector pw >
> rev,
>>so injector is open 100%.  
> But isn't the pulse width also load dependent (ie, no load at 5k uses 
> less fuel than heavy load at same rpm)?  So your observations "at rest" 
> revving up don't fit that hypothesis.
> Not to say you aren't right, just fooding for thoughts.

Huw Powell



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