[Diy_efi] problem with ecu and injector duty

[Daniel Nicoson]

How does it run?

17ms at 5500 RPM is a pretty high duty cycle but possibly you are just at
the upper end of your injector capabilities?  If it is running well at 2 bar
boost it sounds like it must be fun.

What would you expect the PW to be at this power level?

Dan Nicoson

-----Original Message-----
From: diy_efi-bounces at diy-efi.org [mailto:diy_efi-bounces at diy-efi.org]On
Behalf Of Jason M.
Sent: Monday, November 13, 2006 9:06 PM
To: diy_efi at diy-efi.org
Subject: Re: [Diy_efi] problem with ecu and injector duty

Does the fuel pressure regulator compensate for boost pressure?

----- Original Message -----
From: "Damian Long" <bigcow_610 at yahoo.com.au>
To: <diy_efi at diy-efi.org>
Sent: Monday, November 13, 2006 8:44 PM
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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