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

[Ben Swann]

Best I could tell at todays log is the duty cycle never goes over 50% and pulse width
never goes over 10 ms (if that high).  Yet the engine goes flat at around 5k.

 

O2 stays around 13:1 up to the problem point – don’t know what happens then, but a
steady increase in revs up to around 5000 RPM all looks OK.

 

I’ll play with adding/subtracting fuel at 5000 RPM and above later and see what happens.

 

I need to look at the log with the viewer – good ol’ XP likes to do funny things with
permissions and won’t let the program see the log on the computer I copied the file to.
Something that should take 1 min will take me an hour..as usual.

 

Ben

 

  _____  

From: Cody Forbes [mailto:cody at 5000tq.com] 
Sent: Wednesday, October 24, 2007 1:48 PM
To: QSHIPQ at aol.com; benswann at verizon.net
Cc: urq at audifans.com; quattro at audifans.com
Subject: Re: [urq] EFI + MAC-14 maxing ataround 5k RPM

 

It's MAP vs. RPM, for true speed density. MAP vs. TPS (called alpha-N) is only used on
race cars. TPS is only there for accel enrichment, where it gives an extra shot of fuel
as you open the throttle (like an accel pump on a carb). It's all in the programming.

 

At any point if injectors are going 100% duty with no load then it's a problem with how
the tables are tuned or a basic setting issue. The thing is that based on the log file
that Ben sent me his injectores are not going over 70% duty cycle under full load at the
boost level he is currently running. I haven't gotten the chance to look at the most
recent log file he sent nor the settings, but I'll get to that this evening.

 

-Cody Forbes
http://www.5000tq.com
'87 5ktq - Fast.
'87 5ktq QLCC'd plus some
'86 5ktqCD
'86 5k
'86 5k

 

 

---- Original Message ----
From: QSHIPQ at aol.com
To: cody at 5000tq.com ; benswann at verizon.net
Cc: urq at audifans.com ; quattro at audifans.com
Sent: Wednesday, October 24, 2007 12:49 PM
Subject: Re: [urq] EFI + MAC-14 maxing ataround 5k RPM

> And is there programming code for it Cody, or is it somehow prescaled
> in MS?  IMU that MAP is used with TPS to give load.  It seems to me
> that if the injectors are going full open with a no load rev to
> 5krpm, one or both of the load parameters appears to not be working
> correctly.  I would also think that scaling that programming should
> yield some difference in run condition, regardless of what might be
> considered the actual problem.      
> 
> SJ
> In a message dated 10/24/2007 11:39:41 A.M. Central Daylight Time,
> cody at 5000tq.com writes: 
> The MAP sensor is inside the ECU just like stock on our cars, there
> is a 
> vacuum line to the MegaSquirt. By MAP upgrade Ben means to say that
> inside 
> his ECU is a sensor good for 3.5bar (incl. atmo) whereas stock for
> the MS is 
> 2.5bar.
> 
> 
> 
> 
> 
> 
> 
> See what's new at AOL.com and Make AOL Your Homepage.