Itinerant Air-Cooled

Last weekend we went camping and drove about 200mi round-tirp. Over the course of the trip two problems(possibly related) developed. About 15 miles into the trip we filled up with gas. After filling I restarted the engine and had a really fast idle. I drove around the lot and the idle remained high. So, I adjusted it down to a reasonable level.

Drove about 70 miles to the campground. The next morning the bus took a long time to start. Starter cranking away nice and strong, but not starting. It acted like it had been run out of gas and needed be primed up. Once started it ran fine and we drove home.

This starting problem has continued warm or cold. It just cranks away and eventually starts up.


Fuel pressure test: Idle pressure was about 29psi, pulled off regulator vac line and pressure jumped to 36psi. Vac line back on revved engine and pressure was 29-32psi.
Turn engine off fuel pressure immediately drops towards zero.
Pressured up system and clamped hose on 1/2 side near regulator and the pressure still dropped to zero.
Clamped 3/4 side near firewall and pressure slowly drops, is at about 20psi after 20mins.

To me, this test is showing that the fuel pump check valve is not working properly. New fuel pump time?

Is this a reasonable conclusion? Anything else I should check?

Sounds reasonable to me....

The tests you performed are suggesting something funky in the pump side.

I'd swap it out if'n it was in the budget.

yondermtn wrote:This starting problem has continued warm or cold. It just cranks away and eventually starts up.

Pressured up system and clamped hose on 1/2 side near regulator and the pressure still dropped to zero.
Clamped 3/4 side near firewall and pressure slowly drops, is at about 20psi after 20mins.

To me, this test is showing that the fuel pump check valve is not working properly. New fuel pump time?

How did this resolve? We are dying to know.
Colin