Date:         Sun, 8 Dec 2002 15:58:20 -0800
Reply-To:     Matt Ratto <mratto@UCSD.EDU>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Matt Ratto <mratto@UCSD.EDU>
Subject:      CIS pressure tests - now what?
Content-Type: text/plain; charset="iso-8859-1"

Hi all,

still working on the non-starting of my CIS I4 motor I've installed in my
Westy. I've tracked the problem to what I think may be an fuel problem. Mike
Johnson (another list member) nicely loaned me his CIS pressure test kit,
and I ran what tests I could this morning. Here's the results:

Running fuel pump tap closed - pressure 4.9 Bar

Running fuel pump tap open (connected to control pressure regulator) 1.5
rising to 3.5 (or so) as control pressure regulator warms up (from heater
element, not from engine running)

These numbers seem consistent with what the manual states. I also turned off
the fuel pump and let the system sit in order to check residual pressure. As
soon as I turn the pump off, the pressure drops from 4.9 to 2.5 and then
over ten minutes or so drops to 1.5 - I didn't watch it after that.

While I did this, I pulled an injector and watched it as the fuel pump was
running (I wasn't cranking, just jumpered the fuel pump). Without pressing
on the air plate, the injector began spraying intermittantly, pulsing with a
little squeaking noise. If I turn the mixture screw clockwise (richer) the
time between the pulses decreases, but I never get a constant spray. If I
move the plate up about an inch, I get a constant spray, but before that it
pulses.

Also, I checked the fuel pump by pulling the fuel return line and ran it
into a 16 oz. container which it filled very quickly. I should also mention
that the fuel pump periodically makes a deeper vibrating sound, but that it
doesn't seem to change the fuel pressures or the injector pulsing.

So I'm thinking two things; either my fuel distributor is bad (though the
numbers seem right to me) or my injector lines aren't working properly. I'm
thinking the next test is to go the junk yard and grab a good fuel line and
see if it the injector pulses when its connected using this. My current
lines are made with 200PSI hydraulic line attached to banjo fittings I
salvaged from the original fuel lines. I can't feel them swell or pulse if I
hold them while the fuel pump is running.

Any advice?

Matt

-------------------------------------
Matt Ratto
Ph.D. Candidate
University of California, San Diego
mratto@ucsd.edu
http://communication.ucsd.edu/mratto
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