[Diy_efi] Donegan ECU

[Steven P. Donegan]

Well - for track days I simply put dry ice in my fuel cold-can thing -
that solves most vapor-lock style problems and lasts for a couple of
hours. Simple low-tech solution to that problem. Given the lack of
response to my original posting I believe providing PWM fuel pump
control and support for a fuel pressure sensor is useful. 

Given that I normally run at Willow Springs or Buttonwillow during the
winter months temps are not normally a factor anyway.

On Thu, 2007-01-04 at 12:23 -0600, cobraman at insightbb.com wrote:
> My "Edelbrick" ProFlow has fuel pressure controlled with engine vacuum. On track sessions on very hot days, the fuel in the rails will boil under hard braking - accelerator closed (low fuel pressure). When you finally step on it (52 psi), nothing happens until the vapor "recirculates" or is expelled.  Usually takes a second or so.  I don't think dead heading would do any better - probably just need to keep a constant fuel pressure. 
> IMHO, hot fuel should give better economy - easier to vaporize - for those green members.  TomS
> 
> 
> 
> 
> 
> 
> 
> ld
> > consume the gas in the rails well before it got warm :-) However this
> > does raise a point - perhaps my ECM/PCM/EFI computer needs a way 
> > to open
> > a fuel return line and to sense fuel temp in the rails? Any 
> > ideas on how
> > useful that would be in the 'real world' anyone?
> > 
> > On Thu, 2007-01-04 at 14:56 +0800, Mike wrote:
> > > Isnt one of the main needs for fuel return the fact the fuel 
> > is heated quite a
> > > bit in the fuel rail whilst its waiting for injection ?
> > > 
> > > Of course there is a commercial factor as fuel returns used to 
> > be so
> > > much cheaper than any electronics but getting around the fuel 
> > heating etc
> > > 
> > > Also the issue of control feedback is an issue to avoid 
> > vapourisation> during hot start, the good thing about return is 
> > this can be flushed out,
> > > and esp for a turbo as a pressure hold tank can "remember" the last
> > > max pressure and temporarily raise the fuel rail pressure to 
> > this during
> > > start to avoid vapour issues... etc
> > > 
> > > Regards
> > > 
> > > Mike
> > > 
> > > 
> > > 
> > > At 07:23 AM 1/4/07, you wrote:
> > > 
> > > >This sounds cool...is closed loop control of fuel pressure an 
> > oem feature for any new vehicles? Or just something you are 
> > trying out? Are you going to use a PI controller? I am guessing 
> > when you snap the throttle open the PI controller should know 
> > about this quite quickly...not wait to see a drop in fuel 
> > pressure? 
> > > >
> > > >> To add something somewhat useful to the list in this reply 
> > I'll say the
> > > >> Donegan ECM is coming along nicely :-) The input board is 
> > going to fab
> > > >> out at about 3.0 inches by 2.2 inches (exactly matching the 
> > CPU board -
> > > >> ARM based Steve). Inputs designed in are MAP, MAT, 
> > Barometric, Coolant,
> > > >> Throttle, Oil pressure/temp, 4 ea O2 sensors, Crank and Cam 
> > position, 2
> > > >> ea EGT sensors - well pretty much everything everyone told 
> > me should be
> > > >> sensor inputs. Fuel pressure input I'll put on the 'relay' 
> > control board
> > > >> - that will do PWM control of the fuel pump eliminating the 
> > need for a
> > > >> regulator or return line.
> > > >> 
> > > >> Happy New Year :-)
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