The injection pump is a distributor type pump, the same one that
is used on the 6.2 just turned up a bit. It doesn't have any air
leaks. There is a small valve on top of the final filter that
never has any air under it unless I have just changed the
filters. The supply pump is an electric unit that I installed
right next to the tank so the whole supply line except two
connections and about 6" of hose is under pressure. The pump
starts when the key is turned and you can hear the tone change
when the pressure in the system is up to the limit that the pump
can push which is about 7-8 lbs. That is the same amount as the
original engine mounted pump did. I replaced it to make bleeding
the filters easier after replacement and because the engine
mounted pump has a habit of leaking fuel into the oil when the
diaphragm goes bad.
A bit of oil smoke after starting cold but it still starts right
when you turn the key after the glow plugs cycle. No turning over
to speak of just turn to start and it starts right now.
The only thing that matches the problem is a vapor lock problem.
It changes with the fuel supply and outside temp and if you have
ever seen a big block in a van then you know about the clearance
and heat issues in the engine compartment. The 6.5 is the same
size as a big block. The other thing is that I remember it as
starting back when they started with this super low sulfur fuel.
Manfred
Date: Sat, 19 Jun 2010 20:04:29 -0500
From: Peter Frederick <psf...@earthlink.net>
Subject: Re: [MBZ] Hard start problem returns- Update
Mid to late 70's Chevy V8s were terrible about roasting starters.
As
noted, this won't be the case if you have "vapor lock" in the
injection lines.
I'd lean toward a leak on the suction side of the fuel system. I'm
not familiar with that particular engine, does it have a distributor
type pump or an in-line? If it has unit injectors, you definitely
have an air leak or a bad supply pump.
I doubt it could be a compression problem, as that would give you
fits starting cold, not hot, and would produce copious white
smoke as
you cranked and it did not start. No smoke, it's a fuel supply
issue
somewhere.
Peter
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