Naturally, this could be lots of things... sounds like you have spark, so
the coil is probably OK, if you performed your jumping wire trick on a plug
wire (rather than the coil wire), then you've verified that your
distributor is working as well (I think that includes a healthy hall
sender, but the list will correct me if I'm wrong on this). Whether the
spark is healthy enough is another issue, but at least you know it is there.

I'd look for a fuel pump problem first. Electric motors are notorious for
developing heat related problems as they age (think of the many folks
you've seen tapping their starter with a broom handle to get it to turn).
The vanagon fuel pump is also an electric motor.

Do you hear the fuel pump running when you first turn on the key, every
time, even later in the day when the problem crops up? If it is, ignore the
rest of this message, because your fuel pump is not likely to be the problem.

If it's getting balky, the fuel pump may not like to start turning when it
gets warm. That "a few tries at the key" thing points in that direction.
Every time you turn the key, the pump should hum briefly to pressurize the
system.

If the pump is not reliably coming on, there are two other likely links in
the fuel pump chain to consider... the fuel pump relay in the engine
compartment, and the ignition switch (and, of course, the wiring itself,
but you already made sure the connections at the pump are tight, right?).

The ignition switch wouldn't be affected by heat, but is sometimes swayed
by the weight of the keys (and the other dangly bits people like to hang
from their keyrings)... does key wiggling have any effect on the problem?
Do you have 'em in your pocket first thing in the morning, but hanging from
the ignition the rest of the day? My own urban upbringing will not allow me
to park any vehicle with keys in the ignition, but some folks were raised
in gentler places... and this would account for a difference between that
first start and later starts.

The relay could be heat affected (less common in relays, but it happens),
and is much cheaper to replace than the pump... so it's probably worth
trying this before replacing the pump.

Good luck,

Tim

At 11:03 PM 6/29/2005 -0700, you wrote:
>My Tristar was running great with a new engine, a strong 2.1 DJ.  Recently
>it would start perfectly in the morning but during the day, sometimes the
>engine would turn over but not start.  A few tries at the key and it would
>start.  Over the last few days it got worse exponentially.  Now it will
>not start at all.
>
>I think the spark is OK, though it didn't send me across the parking lot
>when it got me : ), it sure made me throw the wire.
>
>Again the battery and starter are fine, spark seems to be OK.  Could this
>be a fuel pump or regulator?  Could it be sensors or switches?
>
>Ever had this before?, where do I "start"? (no pun intended).
>
>Kim Springer
>'89 Tristar 2WD