Date:         Sun, 9 Jun 1996 23:47:03 -0500
Sender:       Vanagon Mailing List <vanagon@vanagon.com>
From:         jgladu@bcm.tmc.edu
Subject:      Vacuum leaks...

The '89 has been having problems idling after starting cold (and sometimes
when warm). Five minutes of warm-up usually fixes most of the problem. When
the problem occurs, it runs fine *until* touching the accelerator, after
which the RPM drop to about 500.  Now the brakes (power-assist (aren't they
all?)) are getting weird.  Intermittently, naturally.  Sometimes the pedal
goes down the normal distance, holds for a second and then keeps going to
the stop.  Non-power brakes are a LOT easier to deal with in The Bozobus...

I got to spend about two hours trying to analyze it.
Did the vacuum-assist-drum-accumulator-thing test, per Bentley.
Stomp on brakes five times (to eliminate residual vacuum).
Start engine.
The brake pedal should go down, a little.
That's what it did.

Plenty of fluid.
Vacuum hoses look okay.
Bentley says test the vacuum check-valve in the engine compartment by
blowing through it both ways - it should only pass air in the direction
"toward the engine".  Couldn't get it out.  Didn't have any replacement
hoses, and the originals proved impossible to remove undamaged.  Stopped
before I wrecked both hoses (big rubber one from 'air collector box' to
valve and the hard plastic one from valve to vacuum line that goes
forward).
The edges of the (2" long) rubber hose between the airbox and the valve
were pretty chewed up, so I installed a small hose clamp there to make sure
I hadn't created a new vacuum leak.

Now the problems are happening much less frequently.

Could a vacuum leak cause these two symptoms?
I was ready to change out the temp sensor II and hope that that would cure
the idling-when-cold problem (and I probably still will, anyway).

Yet more "special" hoses to buy at the dealer's ridiculous price...

Are there any other common leak points in the vacuum system that I should
check for?
What is the 'best' clue that it is time to bite the bullet and replace
*all* of the vacuum lines?


bcnu - G (John Gladu)                 Opinions are just that
Sr NetWorker-Drone & Mac Guru     Baylor College of Medicine
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