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1998 VW Jetta TDI VO Conversion Installation Thread         Return to Main Page

Dual Tank System                                                                      < 1  2  3  4  5 >

WVO & SVO Compatible

Design and Installation:  Nick Pisca, July 2007; 

 

POST-INSTALLATION MODIFICATIONS

 

 

Update February 2008:

 

Busted Fuel Pump after 7 months.

BUSTED FUEL PUMP:

In January, I had a failing switch that had a loose internal connection.  Every bump would kick off the VO pump and switch-over valve.  I replaced the switch, but it may have put stress on the cheapo fuel pump I acquired from Kragen.  Glenn said that my pump would wear out in six months because the plastic pumps are shoddy.  I showed him; it lasted 7 months. 

I replaced it with a Mr Gasket Micro Electronic Fuel Pump, and it seems to be more trustworthy and durable.  They had this at a Pep Boys SuperStore and it had metal components and casing.  It’s still rather small and has a range of 4-7 psi, but it should last longer.  Glenn stated that I’d need a larger pump if I want this to last.

The pump replacement took only 30 minutes and it was minimally messy.  I designed the system to have the pump near the bottom of the kit, so it was easily accessible from the bottom of the car.  Also, I installed an extension for the ground so that I don’t have to remove the bolt located at the top of the assembly. 

 

Busted Fuel Pump after 7 months.

 

Update Late February 2008:

 Second Busted Fuel Pump after 200 miles.

BUSTED FUEL PUMP (Part 2):

So much for Mr Gasket. I ran this for 200 miles and it seized up. That's extremely poor design, because I would assume a supplementary fuel pump would fail with the valve open, so the other pump could still force fuel to the IP. After I ripped it out of the system, I tested it at the battery terminals and the thing wouldn't move.

I'm hesitating to state that the pump is at fault, for I could have fried it electrically. However I doubt this because I had a 5 amp fuse in line to the pump, and that's relatively light.

So now I have to concede that Glenn was right and I should have bought the heavy duty pump from the start.  

 

 

 Third Pump.  Heavy Duty.

Replacement Pump:

I purchased this heavy duty pump at Pep Boys. Prior to reinstallation, I decided to drain the tank, for I estimated that I had about two gallons which should be fast. I pulled the 3/8" fuel hose off the busted second pump and let it drain into a half-gallon milk jug. It seemed to drain slow thru the hotfox (about 1/2 gallon per 2 minutes). Purhaps this is the reason why the previous pumps failed? I didn't have to pump the veg out of the tank--it drained ok, but I envisioned it emptying out of the bottom of the hotfox faster. I suspect a full tank would flow ultra fast.

This larger pump fits nicer than the previous two in the space allotted. It has elbow fittings that don't force the IN and OUT hoses into kinks. After setting it up, I rested it against my aluminum tank and turned it on--it jostled back-and-forth with such force to pound against the tank. I added some insulation to the space inbetween and it's nested directly below the FPHE.

 

 

Update March 2008:

 

 Custom designed Temp Sensor Housing

Custom designed Temp Sensor Cut-Away

New Temp Sensor Housing :

I was getting minimal readings from the existing workaround for my temp sensor probe. I decided to rework this so that more of the probe was submerged in VO. The images above are a 3D model of my current housing; I wish there is a cheap inline-temp probe housing, but I couldn't find one on the market.

One drawback to this housing is that it's brass, so I need to periodically check to make sure that no chicken-skin resides in this "T."

 

 

 

 

Update April 2008:

 

Old Rubber Bundle (where the new aluminum HOH bundle begins) New Aluminum Hosing Bundle

Low Profile Aluminum Tube Bundle:

Here is an image, where I decided to replace my shoddy rubber HOH bundle under the passenger-side front and back doors with aluminum. This reduced my exposure by nearly 2 inches! I sit in the little groove where the lower panel connects to the underbody.

I hope that this aluminum HOH will transfer heat better as well as be more durable.

 

 

 

 

 

Update July 2008:

 

New Aluminum Diesel Supply and Return Lines.  From Selector Valves to Fuel Filter and vice versa.

Low Profile Aluminum Tube Bundle:

After the trip to Alaska and back, I had a substantial Diesel leak. I constantly lost my prime and it took several seconds of hard cranking to start. I thought it was the plastic connector on the return at the fuel filter, because we had to replace the stock plastic lines in British Columbia with 3/8" rubber hose and it looked like there could be a slight fracture in the plastic. After investigating the price of the plastic connector ($38 at the VW store in downtown LA), I decided to see if replacing the rubber lines would fix this. Since this was going to be a complete overhaul of the front end fuel lines, I decided to use the old plastic lines as a pattern. The brake-line pipe bender made a sweet cheap replacement with 3/8" and 5/16" bendable aluminum hose.

I really think that newbie and existing conversions should consider all HOH bundles and individual fuel and VO lines to be bendable aluminum. It removes several of the head-aches and leaves you with a durable line resistant to rubber wear. Also, it's cheaper!

 

 

 

 

 

 

Update March 2009:

Cruddy Plastic Elbow Connector disintegrates after a year and a half.

Plastic Elbow Connector Breaks Easily:

This was terrible. I went out for a weekend drive and a mile from my destination, I smelled anti-freeze. I managed to limp the car all the way there, but lost all of my coolant on the road. The leak occurred at a plastic elbow connectorI used to splice into the heater core line. When I reached back to check out the hose, it was originally just a hair-line crack. But after pulling on the hose, it easily broke off into the end of the heater hose. While pulling the broken element out of the other side, that side too broke off into the opposing heater hose end. What junk.

Luckily, I had a few friends there that lent me access to their wood/metal shop. We found some scrap metal piping, with one with a slight bend. After some chopping and sanding, we had a great substitute splice. (No picture of the new splice)

 

 

 

 

 

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[c] 2008-9 Nick Pisca . www.nickpisca.com/wvo . Waste Vegetable Oil Awareness and Travel . www.nickpisca.com