[Diy_efi] problem with ecu and injector duty

[Mark Riley]

I would hook up a fuel pressure guage and see that the fuel pressure does
indeed rise 1 for 1 with the boost level. I would suspect that perhaps the 
Pump is not keeping up at the upper pressure levels. If the guage shows any
fluctuation at over 10 psi boost or does not make the correct pressure rise
all the way to max boost, the pump is not capable. 

Mark Riley

-----Original Message-----
From: diy_efi-bounces at diy-efi.org [mailto:diy_efi-bounces at diy-efi.org] On
Behalf Of Damian Long
Sent: Monday, November 13, 2006 8:44 PM
To: diy_efi at diy-efi.org
Subject: [Diy_efi] problem with ecu and injector duty

Hi,
   
  I have a rather strange ecu. Most likely not many people have used it
before. It is a Walbro Bike400. You can get some information from here
www.walbro-tdd.com
   
  Since installing and running this ecu I've tuned the vehicle and found
I've needed some very stupid injector opening times. At 2bar boost and
5500rpm I need 17mS opening time!
  Vehicle is 1600cc 4cyl turbo.
  The injectors are Nippon denso 16ohm 550cc/min @40psi. part no
1955000-2020. The fuel pump is a Bosch motorsport unit. 150lph @ 5bar. The
pump, regulator and rail pressure all check out ok so I've discovered that
its an issue with the ecu or wiring to the injectors. Basically the ecu need
to send a 17mS opening time in order to get the injector to open long enough
to supply fuel. The injectors are well sized for the application. 
  Does anyone have any ideas where I should be looking for a solution to the
problem? So far I have the following ideas but now sure if any are relevant.
   
  1. ecu is designed for peak and hold injectors and this is why
  2. wiring to injectors wrong way round. ie. coil polarity wrong
  3. injector voltage offset table set up wrong in ecu
  4. ecu is lying or is just plain cr p and I should burn it
   
  I flow tested injectors. They are ok. Any ideas?
   
  thanks
   
   

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