Date:         Mon, 13 Jun 2011 12:35:43 -0700
Reply-To:     Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM>
Subject:      Re: [Diesel-Vanagon] Re: Debugging air leaks in a Diesel
Comments: To: Diesel-Vanagon@yahoogroups.com, Poppie Jagersand
          <poppie.jagersand@YAHOO.CA>
Content-Type: text/plain; charset="iso-8859-1"

I had an 'air leak in' once that drove me nuts finding it.
It was right where the clear inlet fuel line is installed at the factor onto the banjo bolt fitting.
 
So air was getting in there, but no chance to see bubbles in the clear line. 
That one took a while I must say. The symptom was 'hard starting cold.'

I have never found air getting in at the small return lines myself. 
I have one pump that runs pretty well, but it also leaks pretty nicely.
that one leaks mainly at the main shaft. 

Scott


  ----- Original Message ----- 
  From: Poppie Jagersand 
  To: vanagon@GERRY.VANAGON.COM ; Poppie Jagersand ; Diesel-Vanagon@yahoogroups.com 
  Sent: Sunday, June 12, 2011 10:18 PM
  Subject: [Diesel-Vanagon] Re: Debugging air leaks in a Diesel


    
  Update on the slow progress on getting the Westy road ready. Our vacation got delayed a month so I have not been working on it at the speed I should have. Put in another afternoon in the debugging this Sunday.

  Looks like the unfortunate news is that the injection pump itself has a very small air leak. I have replaced all the rubber hoses for the injector return lines (the usual suspects). Then I disconnected the fuel; in and return lines on the pump and connected two new hoses that I ran directly from a jerry can of Diesel fuel. 

  When starting the pump would first purge the air, so pushed big air bubbles through the return line. However, even after some minutes of running, small air bubbles would remain. I'm not sure how long it takes for the air to be completely purged, but it looked to me as if there was a continuing and not diminishing amount of small bubbles.

  So I'm running out of "easy" things to change. I guess I can change the copper washers on the input and output fuel fittings on the pump. If that doesn't help what else can I try short of removing the pump and replacing seals?

  I'm thinking since the bubbles continue when running, the leak should before the vane transfer pump. I'm not sure what shafts seals should be most suspect, but the input shaft might be one. 

  Let me know what you think and if there is anything else I should test.

  I tried Gnarlie's oil squirting trick on the inlet fittings. Wasn't sure how to get motor oil to the input seal without risking splattering one the timing belt, so didn't do that. (Bad idea since backside of timing belt drives the intermediate shaft, and oil on the belt can make it slip. b.t.d.t. on my previous B2 Passat TD)

  I might also try adding a low pressure electric pump at the fuel tank as several forum members suggested. What do you think about this ebay pump?
  http://cgi.ebay.ca/ws/eBayISAPI.dll?ViewItem&item=220797730011&ssPageName=STRK:MEWAX:IT

  Thanks,

  Martin (and '82 Westy 1,9TD "Poppie")

  --- On Sun, 5/15/11, Poppie Jagersand <poppie.jagersand@YAHOO.CA> wrote:

  > From: Poppie Jagersand <poppie.jagersand@YAHOO.CA>
  > Subject: Debugging air leaks in a Diesel
  > To: vanagon@GERRY.VANAGON.COM
  > Received: Sunday, May 15, 2011, 5:55 PM
  > The most common "hard start" problem
  > I've had with both Diesel Vanagons and VW Diesel cars is a
  > slow air leak allowing air into the injection pump that
  > takes a lot of cranking to purge before it will start.
  > 
  > Culprits are often the injector fuel return lines. These
  > are luckily easy to check. It is harder when it is in the
  > return circuit to the tank. On my Quantum the return circuit
  > was a combination of hose and tube. One tube in an
  > inconvenient location roughly under the rear seat had rusted
  > just enough to allow air in. Took me a lot of time to find.
  > 
  > Now my Vanagon Westy takes longer than usual to start.
  > Pulled the small injection lines. Each shed a drop of fuel.
  > Pulled the injector to pump line at the pump. That looked
  > dry, but fuel hose is fine. (This one I replaced just last
  > year) . Could be tank return line or some problem with
  > pump.
  > 
  > Wanted to pull the plastic return line to tank, but it wont
  > come off. In the past I've pulled it, cut a piece and put a
  > fresh piece on the pump each time. Now I'm at/near the limit
  > of length.
  > 
  > To get it back on I usually have to heat the plastic line
  > with a lighter flame. That sometimes works, but sometimes
  > melts it too much and I have to cut and start over. Is there
  > a better way?
  > 
  > What do you suggest to do when the line becomes too short?
  > Splice in a piece of hose? (add one more junction to
  > leak...) Replace whole line? Can the original style plastic
  > line still be bought somewhere? (I'd hate to have rubber
  > hose all the way)
  > 
  > I had to replace the input line from fuel filter to
  > injection pump a couple of years ago. Canadian dealer no
  > longer has the clear line (where one supposedily can see any
  > air bubbles). Just sold me black rubber hose at $20/metre.
  > 
  > Does anyone have a more principled approach to go about
  > finding air leaks into the Diesel fuel system?
  > 
  > Martin (and '82 Westy 1.9TD "Poppie")
  > 


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