[T3] Car Cures Itself...

[Jim Adney]

On 27 Jun 2013 at 9:24, Tony Rongey wrote:

> I don't think you have to get air in, unless somebody has actually
> sampled the lines and found it there.  I would think that replacing
> 15' of liquid fuel with 15' of vapors would be enough to keep the car
> from starting.  That simplifies the problem to just the boil-off. 

Once the heat soak after shutdown cools back down, the vapor that's 
in there will try to recondense. If that's the way it stays, then 
there would be no air in the lines, and there would be nothing which 
would bubble up into the gas tank the next time I try to prime the 
system. 

So the fact that there are bubbles, means that there is air, not just 
vapor.

> The reason I brought up the check valve is because it's taking five or
> six clicks to start.  My car does this every morning, and it will
> start with two clicks so it sounds like either the check or the
> regulator is bleeding off too fast. 

The check valves are always imperfect, so some priming is often 
necessary, but rebuilding the fuel pumps seldom fixes this. What I 
usually fix are pumps that no longer pump, and the most common 
failure mode is a pump that spins but develops no pressure. That 
happens when the rubber tip on the check valve piston falls off and 
sticks in the outlet hole, thus preventing anything from getting out 
of the pump.

> PS: Are you still fixing the pumps?  I've got one or two that I should
> probably get done to have good spares. 

Yes, I'm still doing them. Pump head rebuilds are $75, that plus 
replacement of the 2 motor body O-rings is $125. Both plus shipping.

As long as the motor still runs and the pump doesn't leak, a pump 
that fails in use only needs the cheap pump head rebuild. A used pump 
that's been stored dry for years will need the full rebuild, because 
all the O-rings have dried out and shrunk. Those pumps will leak 
everywhere.

A pump that's seen a lot of water & dirt, because of a cracked 
overflow hose, may need the full rebuild, just to make sure it's all 
cleaned out and to check the commutator for wear from the abrasive 
dirt.  

I store my used pumps in kerosene so the O-rings can't dry out.

-- 
*******************************
Jim Adney, jadney at vwtype3.org
Madison, Wisconsin, USA
*******************************