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

[fdekat]

Hello Ben:

Some thoughts..

>Message: 4
>Date: Wed, 24 Oct 2007 22:31:58 -0400
>From: "Ben Swann" <benswann at verizon.net>
>Subject: Re: [urq] EFI + MAC-14 maxing ataround 5k RPM

>So we think it might be ignition after all.  I guess I'm not seeing where
the
>ignition
>signal drops out.  I do see the pulse width spike when the RPM drops.  Are
>you looking at the log from today?

>Cody, is there someway to turn on the ignition pulse graph line in the
>logfile?

That would be useful, I'm thinknig. It wold be really good if you could at
least narrow things doewn to problem being either fuel or spark. Until you
nail that down, it's almost as if you are chasing your tail!

Maybe some leds wired  in parallel with the injectors, or coild drive
circuit, so you can have a visual ide of something not happening?


>I remain sceptical at this point about the ignition part, even though it was
>my original speculation.  The more I have looked at the ignition the more it
>looks correct and even an improvement over stock.  Unless I'm getting some
>parasitic draw on coil primary or losing current to coil output, but I don't
>see that.  I do have the coil driving the tachometer - would that be more of
>an effect on the MAC-14 than it was on the MAC-02?

ECU drive a power output stage, driving a coil. I'm thinikng that the tach
laod would be negligable.  I also am running a MAC 11 in my urq (harness &
ECU and all the MAC 11 specific bits), and am using the stock urq tach. No 5K
cutout here..

>How can we see what is happening to the coil primary?  How can you see if
>spark is dying at high RPMs?  Anything else to look at?

I'm wondering where you are taking your MS 'ign' signal from?  With my
messing with MS, I took the signal to MS from the low level ECU output, and
drove the MS opto coupler directly  (no interface capacitors and such. Jsut
as you would drive it with the stimulator).  My though was to get a much
cleaner 'low level' signal, directly from teh ECU, ratehr than a high voltage
signal from the coil, massaged so that MS would be happy.


Fromt the diagram at
http://www.sjmautotechnik.com/trouble_shooting/ecupinpc.html ,  I used pin 22
to drive MS.

 
>I just figured AUDI probably does this a little better.
I'd agree.

=Frank de Kat=