[Mg-t] Fw: No Vacuum

[mark saperstein]

hello stu.

must be an opening on the intake side.  not sure what you rigged up for the
cruise control but that would be the first place to look.. and not just at
the junction of the vacuum line to the intake manifold but especially the
line itself as it runs to the cruise control device and for that matter in
the cruise control device itself.   can you blank ( shut )the cruise control
vacuum as it leaves the intake manifold as a test?  if that solves the
problem then you will know it's somewhere up that end.
  the gasket for the intake/exhaust manifold is one-piece.a backfire could
possibly break it but not likely... and  loose nuts on the fixing studs
could allow plenty of air to enter thereby killing the vacuum too.  ( also
cracks in the manifold etc. )

  but I think best to check the possible fault in the cruise control
department first

all the best,
mickey in phoenix,
   53 TD II
 32 F3 Magna OTS
67 MGBGT


----- Original Message ----- 
From: "Stuart C. Keen, Jr." <simbafish at comcast.net>
To: "MG" <mg-t at autox.team.net>
Sent: Saturday, October 04, 2008 1:34 PM
Subject: [Mg-t] No Vacuum


> I'm at a loss! Drove from the house yesterday and the TD quit after a half
> mile. It had been running just fine, then acted like it was starving for
> gas. No abnormal bangs or noises. Just would not run. Got towed home.
>
> This is a Mark II. BOTH fuel pumps are running. I disconnected the hoses
and
> checked the fuel flow to the bowls. Perfect. The carburetor bowls are full
> of fuel. Checked the spark. Have Pertronix and a Sport Coil. Spark reads
> excess of 20 KV. Removed the spark plugs and noticed they were NOT wet
with
> fuel after I attempted to start.
>
> I have a fitting on the crossover member of the intake manifold. It's
> normally connected to a cruise control system (shame but need the
> assistance). From this port I usually read a steady 20 inches of vacuum.
> Today it fluctuated wildly from 0 to 20. Basically no vacuum. Next I did a
> compression test. All four cylinders are around 150 psi. Assume valves are
> good.
>
> Apparently there is no fuel vapor being sucked into the cylinders (dry
> plugs) due to a vacuum problem. What could be causing this lack of vacuum?
> Where should I look next? I'm at a loss. Could the intake manifold gasket
be
> blown? Why? Would appreciate suggestions what the problem might be and how
> to test.
>
> This is my daily driver (74,000 miles in 9 years) so really want to get
this
> bugger back on the road soon. Thanks for all the help.
>
> Stu Keen
>
> 1951 MG TD Mark II
> _______________________________________________