On 20 Apr 1998, David Hill wrote:
> The car is running rich but not excessively so. To prove it, I put
> Colourtunes in #2 and#6 cylinders. The combustion flame was distinctly
> orange, from tickover up to about 3,000rpm.
Seems it might be slightly rich. Mind you, the PI in its standard setting
always was somewhat on the rich side.
The most probable reason for this is vacuum leaks. It should be
absolutely free of leaks.
It can also be a case of the metering unit having gone out of adjustment,
but that is a rare occurrence.
Check both of these problems by removing the vacuum connection from the
manifold, and adding a short tube with a T-piece to a reasonably accurate
vacuum instrument.
Further detail:
http://www.kvaleberg.com/t_pi.html
> Alternatively, could the line pressure be too high.
No. Unlike modern injection systems, the line pressure does *NOT* effect
the amount of fuel injected, and is not a very critical parameter. This
is because the fuel is actually *metered* in the metering unit.
A too high line pressure would cause problems with the pump overheating
during the summer.
> Also, I can't hear fuel being returned to the tank so the return line may
> be blocked.
>From where?
The metering unit return line only carries whatever fuel that
leaks from the metering unit - nothing that will upset your metering.
The pressure regulator should carry a significant flow, enough to be
audible with the pump running and engine stopped. If there is no flow,
either the pump is worn and the pressure is too low, or the pressure
regulatur is gummed up. Again, this will not upset the metering.
Egil
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Email: egil@kvaleberg.no Voice: +47 22523641, 92022780 Fax: +47 22525899
Snail: Egil Kvaleberg, Husebybakken 14A, 0379 Oslo, Norway
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