How to prime fuel filter without taking a diesel shower

christoj879

New member
Joined
Jul 26, 2010
Location
N/A
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I replaced the fuel filter, and stupidly didn't put fuel in the new filter. I did a few key cycles, as well as cranking until the car beeped and the the display said STOP to no avail.

Each time after doing this, the T junction would pop off under pressure when I tried to remove it to see if there was fuel in the filter. The last time it did a lot of fuel came out with it. I tried the other lines and each one shot fuel out. Once this is done I now need to wash the engine bay and car :)

The car still isn't starting - what should I be doing?
 

CharlieT

Veteran Member
Joined
Dec 10, 2008
Location
Houston, Tx
TDI
Audi TTqTDI, B4V, B5.5V, '12 NMS SEL
If you didn't fill the new filter prior to install, then you now have a large air bubble circulating through the tandem pump. This air bubble gets compressed, hence the spray of diesel and air each time you remove a line.

From where you are now, best option is to :
1. Remove T and fill filter with diesel. Reconnect T
2. Make sure all lines are connected to new filter, no leaks
3. Remove the hose from the rear of the Tee, this is the hose that RETURNS diesel from the tandem pump (trace it back to check)
4. Cap the open port on the Tee (else you will suck air back into the filter)
5. Connect a mityvac to the hose you just disconnected (from the tandem pump), and pump. You will need to pump quite hard (20"+), you are pulling fuel all the way through the filter and tandem pump from the tank.
6. Once you get a clear stream of diesel, no bubbles, reconnect everything.
7. Should start right up, cycle key a few times if needed (without starting) so the lift pump pushes fuel through.

To prevent this in the future, fill the new filter with diesel prior to installing, then just cycle the key a few times and it will start fine.
Another option is to fill the filter with diesel purge and hence clean your injectors at the same time.
good luck.
 

Lug_Nut

TDIClub Enthusiast, Pre-Forum Veteran Member
Joined
Jun 20, 1998
Location
Sterling, Massachusetts. USA
TDI
idi: 1988 Bolens DGT1700H, the other oil burner: 1967 Saab Sonett II two stroke
I've not had problems in cycling the key a few times to operate the lift pump to prime the empty filter. I've cranked for perhaps 10 seconds total after that until the engine ran.
Yes pre-filling the filter would reduce the 10 seconds of starter operation, but I don't think it worth the effort when a lift pump can fill the filter equally well.
 

christoj879

New member
Joined
Jul 26, 2010
Location
N/A
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It's working. I didn't have a Mityvac but I have this http://www.harborfreight.com/brake-fluid-bleeder-92924.html and tried it but without much luck.

Unfortunately my starter took the brunt of priming the car. But now my wife won't kill me, I'm very glad she went to a ball game today while I did this.

I had just done a gasser before this one today and was in gas mode (small filter, starts right up) and forgot to fill it. Made the day that much more interesting :)
 

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis, MO
TDI
There are just too many to list....
I just cycle the key about 10 times, start the engine, then shut it back off right away... cycle 10 more times, start the engine. It may stumble, but it generally picks up and stays running. If it stumbles and dies, cycle the key 10 more times, then crank with the accelerator pedal about 50% until it sputters and starts, then allow to idle for about 30 seconds.

Keep in mind, I also only have the lines disconnected from the filter for about 30 seconds at most, and plug the first two I remove so nothing dribbles out.
 

christoj879

New member
Joined
Jul 26, 2010
Location
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Now for an interesting conundrum. Following the change I took it for a test drive and floored it and then checked for leaks and everything was well. However there's now a whine that tracks with RPM's (louder when higher) and when I take my foot off the pedal the engine stumbles once when it returns to idle.

Thoughts?
 
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