I'm posting for a friend on this one, but I thought maybe this forum could help. I have a friend with a 2002 Golf TDI with about 150K on it. Last winter they were running ULSD when the car had some big problems (timing belt related... you can guess what happened). The car sat all winter. Fast forward to this spring, the car is fixed and back on the road. They switch back to homebrew B100 and start to have problems with the car loosing prime (it seems) if it sits for more than a few hours. It will be hard to start, or may start, stumble, and die, then take a little cranking to start again. Once running I'm told it works great.

My question is, where should they START looking? Obviously it could be a leak anywhere allowing air to get in, but are their some hoses or fittings that have more problems then others? They have replaced the fuel filter, but so far that's it.

What should be the first course of action? I am used to the Gm 6.2 and now a cummins, so the TDI isn't my shadetree specialtys.

Thanks,
Liam

Did the dealer and other mechanic actually bleed the system as it should be done? This involves using a pump to pull the fuel through the fuel filter, then hooking up to the fuel pump and pull it through the pump and then opening injectors #1 and 2 and bleeding them.

I had the same thing happen with my 2003 Beetle and it was not until we did the above process was I able to get all of the air out of the line. Many dealers bypass all of this by filling the filter and it was usually run for a short period of time as yours did (and mine). It took us about 45 minutes to fully bleed the system.

If this does not work, let us know.

is that to say that the proper way to replace the fuel filter is to use this method? Simply running the car for a few hours (driving) won't work any small bubbles through the system?

What did they use for a pump?

Thanks.

Running the car will not get all of the bubbles out of the system. I ran mine for several days (short distances) thinking it would correct the problem. As I live in a rural area, if it cut off, I could leave it in someone's driveway for a while and then it would finally start. It was not until I did this that the problem was corrected.

I do not know the name of the pump, but Advance or AutoZone should know what it is. It is used to bleed the brake lines of large trucks as well. Also, can be used to change the oil in your car as it will draw the oil out through the tube and you do not have to go in from underneath. However, the one used for this has a larger capacity than the one used for brakes and fuel. The cost is about $30.

I will try to find my detailed information, and pm it to you. It has been awhile.

Driving it any distance should clear the lines of air. So it's either sucking air in again somewhere, or like my 6.5 it was electric fuel pump not holding its prime whenever it sat overnight. I fixed that by putting a check valve in line back at the tank. That was cheaper than replacing a pump that otherwise is still working good.
Good luck.

I drove mine about 100 miles and it did not fix the problem. I would sure try the simple fix first of bleeding it properly.

Go to Fredstdiclub.com and you will read what I am talking about.

I tried everything else first, then went back to the simple explanation.

"if it sounds like horse hooves, look for a horse"

I had the same problem with my 2001 VW Golf TDI. The solution was to change the Pump Head O-Ring with a Viton seal. You can find it here - http://www.dieselgeek.com/servlet/Detail?no=430

Sheepfarmer and adamrc gave good advise.
There are additional sources of air that can leak into a fuel systema nd cause your symptoms.
1. O-ring under fuel filter.
2. Injection pump main shaft seal.
3. Small Inter-injector lines.

4.Could also have a leak at any point between the tank sender and the fuel filter that will suck air in, cause it's under vacumn.

5. Also a cracked fuel sender. It leaks when the tank is near empty.

Fuel leaks can occur at the injection pump Head, Top Cover, and Quantity Adjuster

This message has been edited. Last edited by: jburke,

quote:

Originally posted by ShadowB:
Driving it any distance should clear the lines of air. So it's either sucking air in again somewhere, or like my 6.5 it was electric fuel pump not holding its prime whenever it sat overnight. I fixed that by putting a check valve in line back at the tank. That was cheaper than replacing a pump that otherwise is still working good.
Good luck.

hey shadow, do you think you could elaborate on this a little more. My car is doing the same thing that everyone in this thread is describing. Trying to figure what the fastest cheapest thing to do is to fix it. Any help would be great. Thanks