[Diy_efi] problem with ecu and injector duty

[Daniel Nicoson]

At 550 RPM on a four cycle engine he has just slightly over 20ms available
(6000 RPM a PW=20ms is 100% duty cycle).

Dan Nicoson

-----Original Message-----
From: diy_efi-bounces at diy-efi.org [mailto:diy_efi-bounces at diy-efi.org]On
Behalf Of Carter Shore
Sent: Tuesday, November 14, 2006 11:05 AM
To: diy_efi at diy-efi.org
Subject: RE: [Diy_efi] problem with ecu and injector duty

I have not looked at the link yet, but are you sure
that the ECU is sequential, rather than batch?
The injector pulsewidth/duty cycle only makes sense if
you know what the underlying pulse frequency is, ie
what's the dead time?

--- Mark Riley <turbotuneusltd at triad.rr.com> wrote:

> 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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