From a point at sea, to the circles of your mind, this is Artful
Dodger:
Almost certainly. A small metal box that has two pressure pipes (fuel)
connected to it next to the electrical connector.
Unplugging it will affect it in a similar way to the auxiliary air
valve - it takes several minutes to have an effect. In this case, if
it is working properly, on a warm engine the fuel mixture will
gradually enrich, causing the engine to idle unevenly and have flat
spots under acceleration, like you had just pulled the choke out on a
carb. engine.
Disconnecting it from cold shouldn't make any difference to cold
starting, but as the engine warms up it will be like leaving the choke
out.
I suppose it is possible that the overall regulation is no longer
right, so it is regulating the pressure incorrectly throughout its
range. Unfortunately there is no adjustment to be made to these.
Haynes does it's best to confuse you here - the airflow meter flap on
the V6 illustrated goes *down* as air goes in, unlike the in-line
4cylinder, where it goes *up*.
In your case, the fully closed, at-rest position is when the plate is
horizontal, filling the hole at the bottom of the dish-shaped opening.
The 1/4 inch downward movement is normal and is intended to let any
pressure from a backfire escape past it.
If you grip the bolt-head in the middle of the plate you should easily
be able to pull it upwards through an arc, until the arm it is
attached to (underneath) cannot move any further. This is probably
only and inch or two at the bolt head. There may be a little
resistance against residual pressure in the fuel system, but movement
should be smooth and unobstructed throughout the range.
As the flap moves upwards, it moves a small plunger in the fuel
distributor that allows more fuel to the injectors.
If by 'fuel control unit' you mean the fuel distributor, then these
very very rarely go wrong. Even it they become a little worn there is
an adjustment. Total failure is very unlikely (despite my experience
mentioned elsewhere). And a new one would be hilariously expensive.
Eliminate *everything* else and treble check your work before you
replace this. And hunt around for a good secondhand unit.
--
Stewart Hargrave
A lot faster than Royal Mail
For email, replace 'SpamOnlyToHere' with my name
