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Big injectors - engine not running right - help in

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Big injectors - engine not running right - help in #1
mailbot Mail List Archive Bot ., Online, USA	Topic Creator (OP) May 2, 2009 12:31 PM Joined 15 years ago 227,243 Posts

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Mail From: Ian McCloghrie <(email redacted)>

On May 2, 2009 "Ray Ayala" wrote:
> the fuel pressure, but keep in mind that when the pressure falls below the
> injector's minimum rated fuel pressure it starts to dribble the fuel out
> rather than spray it.

Clearly this calls for a displacement increase! :)

--Ian

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Big injectors - engine not running right - help in #2
mailbot Mail List Archive Bot ., Online, USA	Topic Creator (OP) May 2, 2009 12:35 PM Joined 15 years ago 227,243 Posts

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Mail From: Bruce Labitt <(email redacted)>

Ian McCloghrie wrote:
> On May 2, 2009 "Ray Ayala" wrote:
>
>> the fuel pressure, but keep in mind that when the pressure falls below the
>> injector's minimum rated fuel pressure it starts to dribble the fuel out
>> rather than spray it.
>>
>
> Clearly this calls for a displacement increase! :)
>
> --Ian
>
>
>
That would be fun too! Got a nice LSx for me?
-Bruce

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Big injectors - engine not running right - help in #3
mailbot Mail List Archive Bot ., Online, USA	Topic Creator (OP) May 2, 2009 03:54 PM Joined 15 years ago 227,243 Posts

This read-only message was archived from a public mail list.
Mail From: Bruce Labitt <(email redacted)>

Ray Ayala wrote:
> The main gotcha with injectors is that they have a minimum on-time
> caused by a phenomenon known as magnetic hysteresis. If you give them
> a shorter electrical pulse width than their minimum drive time they
> just don't open at all, and once they do open they won't close any
> sooner than their minimum on-time. For any given fuel pressure the
> minimum amount of fuel delivered per squirt is proportional to the
> size of the injector (flow rate multiplied by the minimum on-time).
> When the idle rpm is higher the number of squirts per second is higher
> too so the minimum amount of fuel delivered per second rises just as
> fast as rpm rises. In other words, if you can't idle lean enough at
> 800 rpm, you can't idle properly at any higher rpm either. The only
> way to reduce the minimum fuel volume delivered per squirt is to
> reduce the fuel pressure, but keep in mind that when the pressure
> falls below the injector's minimum rated fuel pressure it starts to
> dribble the fuel out rather than spray it.
>
Umm, that is not very encouraging. Is the minimum on time lower with
peak and hold (low impedance) injectors? I know some folks (probably on
this list) have solved this problem. How have you done it?

-Bruce

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