Adventures in F.I.

[Schmitt@aerovironment.com (Schmitt, Frank)]

This past weekend I did a bit more tinkering with the Type 3. I checked the
compression. One of the cylinders (number 1, I think) was low at 75 psi. The
others were around 115-125 psi. The oil light went out after a bit of
cranking.

There seemed to be a VERY rich mixture entering the cylinders (liquid fuel
on the spark plugs), so I thought I'd take out the fuel pump fuse for a bit
to see what would happen. The engine started after about 10 seconds of
cranking, ran like crazy (4000 RPM?) for about 20 seconds, and then ground
to a halt (no doubt starved of fuel). This was with my foot off the pedal. I
replaced the pump fuse for a few seconds again, tried it again, and the same
thing happened. At one point I got it to run for about 2 minutes by pulsing
the fuel pump fuse.

I came up with the diagnosis that I either had a faulty (or poorly adjusted)
pressure regulator, or I had a stuck (open) cold start valve. The latter
doesn't look too likely, as pinching off the fuel supply to the cold start
valve with a couple of pennies and a pair of vice grips didn't seem to help.

A couple of questions. First does anyone know if the FI system runs off the
same fuse as the fuel pump (Haynes didn't show any schematics for FI cars)?
Second, does anyone know where to get a gauge to test fuel pressure?

TIA,

-Frank