Re: [MV] CUCV New Problem

From: chance wolf (chance_wolf@shaw.ca)
Date: Mon Feb 07 2005 - 12:47:10 PST


----- Original Message -----
From: "Stu Ellis" <stuinnh@mvnut.us>
To: "Military Vehicles Mailing List" <mil-veh@mil-veh.org>
Sent: Monday, February 07, 2005 11:30 AM
Subject: Re: [MV] CUCV New Problem

> Nothing black on top except vacuum modulator that is for the trans.

Vacuum Regulator Valve mounts to the side of the pump - not the top - is
actuated by the throttle-shaft running through the pump from driver's side
to passenger's. If you're staring at the front of the engine and the front
of the pump, about a six-inch length of rubber 5/16 hose goes up from the
steel return line and right on to the top-front of your injector pump. What
that hose attaches to looks like a simple hose fitting but it's not. What
you're looking at is, in fact, the Cold Advance Valve itself. If you take
the hose off you can remove the valve with either a 9/16 or 5/8 deep socket
(forget which - 9/16 I'm pretty sure), and then follow the earlier
instructions regarding checking/cleaning. Sometimes when they rebuild the
pump they do a cursory examination of bolt-ons like this valve, and might've
reused your old one after mistakenly judging it serviceable.

> On top
> of pump all grey. Hose goes to assembly that has wire terminals and seems
> attached to top with 2 screws.

3 screws. The third one usually has the ground tab for the Cold Advance and
Shutoff solenoids mounted to the inside top cover of the pump itself. Might
want to ensure there's a good ground connection there while you're looking.
There are two spade terminals on the top of the pump. The first ("wide
one") operates the solenoid which opens the fuel supply to the injector pump
while the ignition is on, and shuts it all down once you turn the key off.
The second ("narrow one") has 12V applied only in "cold" conditions before
the vehicle warms up, and operates the Cold Advance solenoid mounted in the
top of the pump alongside the other solenoid previously mentioned. The
Green wire which connects to the narrow tab on the injector pump also splits
off to provide a connection to the Fast Idle solenoid which keeps the
throttle open a little wider when cold, and which naturally turns off along
with the Cold Advance solenoid once the engine reaches operating temperature
and the sensor responsible for triggering them goes open.

> I took hose off and filled nipple with
> solvent , and sprayed it good inside. Hooked back up and ran with no
> change. Pump rebuilt about 3 years ago.

Eeeyikes. Stay clear of traditional solvents because all the seals and
what-not in the pump are designed to be immersed in diesel only, and their
reaction to extra-curricular chemical compounds might not be too
predictable. I used to blow the Cold Advance Valves out with WD40 through
the nice, long, red nozzle they give you with the can, or sometimes a shot
of ether/starting fluid if that's all I had.

Failing all that, I dunno what to suggest. You could make a trip to the GM
dealer to see if you can get a replacement Cold Advance Valve just in case
the rebuilders reused your old one. The GM part number is 14067420, but for
whatever reason they just call it "Connector, Return Line" as opposed to
anything more descriptive. If that doesn't work and nobody else has any
suggestions - I guess it's off to the diesel shop for a diagnostic.



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