re. Fuel Distributor Connectors

Alan Pritchard apritchard at
Mon Feb 2 10:46:39 EST 2004

Fuel pressure is controlled by the large bolt on the front of the metering
head, I believe it can be shimmed to adjust it. The other pressure control
is the unit on the side of the block (if you have it) which has a brass cap
on its underside. This can be removed and adjusted.

Best Regards,

Alan Pritchard,
Network administrator.

Seaeye Marine LTD.
+44 (0)1329 289000

 -----Original Message-----
From: 	Marc Boucher [mailto:mboucher70 at] 
Sent:	02 February 2004 15:45
To:	Ben Swann; quattro at
Subject:	Re: re. Fuel Distributor Connectors

Plate rises and falls with slight amount of force.  I've previously measured
the resistance across the potentiometer during idle and this confirms that
the plate is rising.

There are bolts in the side of the fuel distributor near the top.  When
these are pulled, there is gasoline.  I would have guessed that these led to
the upper chamber but since there's gasoline there but none coming from the
nozzles, these bolts must lead to the lower chamber?

The next scheduled investigations include:
pulling the connections to and from the fuel pressure regulator, confirming
that there's flow and trying to gauge if the pressure is high enough (maybe
trying to stop the flow with my thumb?)
measuring resistance across diff pressure regulator (its been suggested it
should measure 200 ohms at rest )
restarting car to run on cold start valve, with ammeter in line with diff
pressure regulator, and measuring current...try to keep car running on cold
start valve until it reaches normal operating temperature and seeing if this
changes anything...Anyone know if the cold start valve is designed to
operate continuously for 20 minutes without burning out? 

I'm hoping that these investigations will tell me whether my next step is to
a) fuel pressure regulator (I'd heard there was an adjustment on them but I
can't find it)
b) diff pressure regulator
c) fuel distributor and air metering unit


----- Original Message ----- 
From: Ben Swann 
To: Marc Boucher 
Cc: quattro at 
Sent: Monday, February 02, 2004 10:05 AM
Subject: re. Fuel Distributor Connectors


When metering plate is lifted, you should have fuel spewing out the top and
great gushes of fire hazard.  If not, then something is blocking fuel flow
to the injector lines and your trouble is definately in the metering head.
You did a valid test - It may have been safer and saner to pull the
injectors, but this did narrow the problem.

Did you experience resistance when air flow plate lifted, or did it rise
with a slight amount of force?  


[Previously, in testing the fuel distributor and metering system I'd done
the following:

Disconnect an injector line from the top of the distributor
Lift the air flow plate
Operate the fuel pump

At this point, since no fuel came out from the fuel distributor it was
concluded that this was the failure point.

I'm wondering if the bolts that connect the injector lines aren't perhaps a
special design that don't permit fuel to flow unless the lines themselves
are connected...Does anyone know if this is the case or if this test seems

Incidentally I've tested and there is fuel flowing both from the pump and
back to the pump via the return line when the pump is activated.  Has not
been pressure tested yet.

quattro mailing list
quattro at

More information about the quattro mailing list