Date:         Mon, 8 Mar 2004 03:06:10 -0500
Reply-To:     Alex Towner <altowner@COMCAST.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Alex Towner <altowner@COMCAST.NET>
Subject:      Re: diesel altitude compensation
Content-Type: text/plain; charset="iso-8859-1"

There have been way too many posts now to include them here, but the problem discussed is diesel Vanagons that puke smoke under load. The basic solutions are always to check the injection pump timing and to test the injectors for  good spray pattern and opening pressure on a special Bosch tester. I'll elaborate on some other possible solutions (already mentioned) when the basics fail.

1) Install a factory altitude compensator.

If I remember right, I think many of the 1989-92 Jetta diesels came with an altitude compensation device next to the fuel filter. In additon, they had a device on top of the filter to recirculate the fuel and keep it warm (partially bypassing the fuel's return to the tank). It would certainly be worth the effort to try and install the factory compensator on a Vanagon diesel to see if it will cut down on smoke.

2) Adjust the enrichment of the injection pump.

This is done by adjusting the horizontal screw (with locknut) that is above where the injector lines exit the pump. A metal collar is crimped over the screw at the factory to prevent tampering. With the engine off, remove the collar and loosen the locknut being careful not to move the adjusting screw. I always mark the original positon of the screw so I can return to the stock setting if necessary. By turning the screw clockwise, IIRC, the level of fuel delivery is increased. Only turn the screw in very small increments; a slight adjustment can make a big difference. You can tell if you are going in the direction you want by monitoring the idle speed. The idle will increase when you are increasing the fuel delivery; decrease with a reduction in fuel delivery. This also means that the idle speed will need to be adjusted to get the engine to idle at stock RPM.

Be mindful of changes in the vehicle's performance when you adjust the pump. I once bought a used pump that eliminated smoky emissions from the tailpipe, but the car became even slower than normal; I had to increase the fuel delivery of the pump to avoid becoming a rolling roadblock.

Hope this helps.

Anyone need 1.6 turbodiesel parts?   ;)