Tech FAQ Thread

Technical questions and answers concerning all models of VW diesel vehicles.

Moderator: Fatmobile

admin
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Tech FAQ Thread

Post by admin »

The majority of respondents to the Suggestion Box poll about a Frequently Asked Questions thread wanted to see one, so here it is.

Post your tech tips, diagnostic troubleshooting procedures, observations and repair techniques. You can also include links to existing threads here at the forum, or to those at other forums. Including photos is always a good way to get the idea across.

The only "rule" in this thread is that it is not intended to be a discussion thread. Please post only statements, not questions or discussions, those can be posted in other threads in this forum. Any question/discussion replies in this thread will be removed, or moved to their own topic, as suits the moderators.

Have fun with it!
Guest

Post by Guest »

Alright, I'll get things started by supplying links to a couple of useful threads here at vwdieselparts.com:

List Your Homemade VW Specialty Tools Here!


Need help detaching exhaust manifold...C-shaped clamps?
hoyt
Diesel Freak
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Location: Battle Ground, WA USA
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Injector return hoses

Post by hoyt »

Info posted by Sharkey:
If you want to put an end to replacing the injector return hoses, don't use the crappy rubber hose.

Instead, go to an industrial tubing and hose jobber and purchase a length of ¼" nylon air brake line. It's about $.50/ft. This is rigid tubing, but it fits perfectly over the barbs on the injectors and return banjo on the pump. It's unaffected by petroleum diesel and Biodiesel. ~And~ it comes in colors, black, red and blue!

One warning: This stuff is one-time use. If you attempt to pull the tubing off to remove an injector, etc, either replace the tubing, -or better- cut the length long when you first install so you can trim the end and use a fresh bit of tubing on the barb next time. I've been using this stuff for a few years now and I'd never go back to rubber (mostly because the Biodiesel turns rubber to goo really fast!)
--John
'82 Diesel Vanagon
hoyt
Diesel Freak
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Location: Battle Ground, WA USA
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Got Electrical Problems??

Post by hoyt »

More from Sharkey:
Broken record time = Check your grounds. Battery-to-engine and battery-to-body. 99% of all electrical anomolies in VW's are due to bad grounding.
--John
'82 Diesel Vanagon
hoyt
Diesel Freak
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Location: Battle Ground, WA USA
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Biodiesel conversion info

Post by hoyt »

More from Sharkey:
OK, here's the "conversion" process for Biodiesel:

1) Replace the fuel lines with synthetic

2) Carry a spare fuel filter

B100 will turn the fuel lines under the hood into sticky black goo in a fairly short time, especially if they are old. B20 will do the same thing, but it will take a little longer.

Unless you are fantastically wealthy and can afford to replace everything with Viton lines (~$12/ft), use urethane for the 1/4 and 5/16" lines and ¼" nylon air brake tubing for the injector return lines. Urethane is available from motorcycle shops at $1/ft and nylon from industrial hose suppliers, or perhaps large truck repair shops, $.50/ft.

Eventually, the lines back at the tank will rot out also. Generally takes longer since there is less heat and grease to have weakened them. You can use urethane for replacement of this, but there is one hose that is 3/8" at the tank and ¼" at the supply to the engine compartment. I've had to make some custom silver-soldered adapters to be able to join two different sizes of urethane to replace this piece.

The spare fuel filter is because ot the solvent aspects of Biodiesel, but also beacuse of it's ability to bond to dirt.

Diesel doesn't evaporate and leave behind varnish the way gasoline does, so there normally won't be any "deposits". If a tank and fuel system has been filled with clean fuel, protected from contamination by water, and has no rust, then there will be no problems with filter clogging.

Biodiesel has an unusual ability to bond at a molecular level with tank and fuel system contaminants. Any debris, rust, water, dirt, or other contamination which has been lying dormant in the tank will be acted upon by the Biodiesel and put into suspension, eventually getting sucked into the filter. After a time, the filter's had enough, and you stop driving due to fuel starvation. Worst case, the filter collapses and the crap gets sucked into your injection pump. At the least, high vacuum draws through a partially-clogged filter are hard on the injection pump's internal vane pump.

Common wisdom is to simply change the filter after a couple of tanks of either B20 or B100 ~and~ carry a spare.

Biodiesel costs more, but it's value far exceeds it's price. You will like using it! Even in lower percentage blends, it cleans up the petroleum diesel smell of your exhaust quite a lot. If anyone wants the environmental and pollution rap, I can lay that on you too.
--John
'82 Diesel Vanagon
Big Bad Subaru
Glow Plug
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Post by Big Bad Subaru »

I've read that putting 1 quart of automatic tranny fluid in your tank about every third tankfull, helps to keep the injectors clean, etc...


I also found out the other night, that if it is late at night, all the gas stations are closed, and you aren't quite sure if you are going to make it home, you can go to the 24 hour food store and buy a gallon of veggie oil and make it home without having to walk :-) Ran just fine, fired right up the next morning, and made it to the gas station to fill the tank with some of that yucky dino fuel...
1982 Subaru GL 4WD Sedan
1.6 liter 265,000 and still tickin
1987 Subaru GL Turbo Wagon
1.8 Liter Turbocharged Rice Killer
1982 VW Rabbit Diesel
glovert

Post by glovert »

To bleed your diesel fuel system, apply pressure to the fuel tank with air after you fill the tank, stuffing a rag around the filler hole. You can then bleed to the pump before turning the engine over. break loose the nuts on top of the injector lines and crank you get fuel immediately.

This takes less time, and keeps the starter and battery from grinding away.
hoyt
Diesel Freak
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Location: Battle Ground, WA USA
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Is your Diesel smoking??

Post by hoyt »

The cause might be one of these:

Black smoke = overfueling = too little air to combust the quantity of fuel.

White/blue smoke = too little time to completely combust fuel (generally a timing problem, or leaking injectors).
--John
'82 Diesel Vanagon
Fatmobile
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Joined: Wed Oct 30, 2002 10:28 pm
Location: north central Iowa

FAQ post

Post by Fatmobile »

I lost alot of topics when the site fell. Here's a few but I'll have to build this post back up.

How to change the o-ring around the high pressure end of the injection pump:
Andrew (libbybapa) tried it on the bench and found a way to swap this fat o-ring while the pump is still on the car. Big time savings:
viewtopic.php?p=30253#30253

Home made specialty tools:
viewtopic.php?t=771

Changing a crank seal:
viewtopic.php?t=7112

Draining the coolant:
viewtopic.php?t=7111
Last edited by Fatmobile on Thu Sep 13, 2007 2:47 am, edited 14 times in total.
ricosuave
Cetane Booster
Posts: 64
Joined: Tue Jan 27, 2004 4:08 pm

Post by ricosuave »

Here is a useful link - A forum of Bentley technicians that will answer any questions about specific model cars.

http://tech.bentleypublishers.com/categ ... tegoryID=6

Youre welcome!

Rico
Now: 00 Golf TDI, 03 Jetta Wagon TDI - :)
Then: 69 SC Transporter, 84 Rabbit GTI, 87 Fox GL, 91 Golf IDI, 97 Jetta IDI - :|
"Everything I save by driving diesel I put back due to poor German engineering and crappy Mexican workmanship!" :(
abcdefg1675
Glow Plug
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Joined: Sun Jun 05, 2005 8:21 pm

Post by abcdefg1675 »

Removing a waterpump pulley that has no belt on it, which has rusted up bad (my experiances at the junkyard).

The pump pulley bolts were rusted on very good. I took two 1/2 Inch wrenches, and tried to make a cheater-bar and pry off the bolts. The first problem was trying to keep the pulley from moving. I tried shoving belts and hoses between the pulleys, nothing worked.

What helped me? I took both wrenches and pushes opposite directions on two bolts. One would tighen, one would loosen. Put the wrench over the loose one, and push the wrench toward the center of the pulley. The wrench will be locked onto the bolt, and the side will be hitting the center of the pulley. Now It let me loosen all of the other bolts.

I will take pictures if my words do not explain well enough.
1981 Diesel wabbit - The handling of a sports car, and the soul of a turtle combined into one wobbly $500 car.
guest

Post by guest »

If you're going to run any percentage of biodiesel in your car, you should get a fuel pre-heater. There are lots out there. Diesel-therm is what I use. Or you can order them from Mercedes. They have them on the Sprinter vans, I know this for sure. This will significantly reduce the chances of having your fuel filters clog up. Also great for cold starts.
Josh
Turbo Charger
Posts: 374
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Location: Algonquin, IL

Better to use kerosene

Post by Josh »

I must say, you'd be far better off running kerosene as a stop-gap fuel. Kerosene is sold in many of the same types of stores, and is cheaper. Best is to of course pack a gallon of fuel in your trunk in a small canister. I've a one-gallon red plastic tank. Every few months when I fill up, I'll pour it into the main tank, and then refill the small tank from the pump. This keeps the fuel fresh, just in case (never had an issue with running old fuel).

-Josh
Big Bad Subaru wrote: I also found out the other night, that if it is late at night, all the gas stations are closed, and you aren't quite sure if you are going to make it home, you can go to the 24 hour food store and buy a gallon of veggie oil and make it home without having to walk :-) Ran just fine, fired right up the next morning, and made it to the gas station to fill the tank with some of that yucky dino fuel...
Fatmobile
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Joined: Wed Oct 30, 2002 10:28 pm
Location: north central Iowa

FAQs

Post by Fatmobile »

Let's not turn the FAQs into a place for discussion.
It would work better if you made the comment in another thread or forum and posted a link to it here, with a brief description of what the link contains.
libbybapa
Turbo Charger
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Joined: Thu Nov 17, 2005 1:05 am

Post by libbybapa »

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