Air in fuel system

HappyWagon

Member
Joined
Jan 18, 2018
Location
Ohio
TDI
2005 Jetta
Read the thread about install of in-tank fuel pump. When I removed the pump I found black flakes of sort floating around in there. So I blew out fuel system with air hose. New pump and filter installed. But must still have air in system because not won't run. By the way 2005 jetta TDI. 360000 miles. Any help would be appreciated. More info on next post.
 
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KLXD

Top Post Dawg
Joined
Aug 22, 2009
Location
Lompoc, CA
TDI
'98, '2 Jettas
I don't know much about PD motors but I do know more info will help the guys familiar with them.

A little history? New problem? Bought it this way? Etc...
 

HappyWagon

Member
Joined
Jan 18, 2018
Location
Ohio
TDI
2005 Jetta
I have had the car for a while, about a year. Sat for most of that. Ran when I parked the car. Then when I decided to drive it, fuel pump was dead. So I pulled the pump and found what I was told was allgy. So I tested pump. And it was bad. Bought new aftermarket pump. Cleaned tank out with clean towels and fuel additive. Then used air hose to blow out the lines from tank to filter, replaced filter. From filter to tandem pump. Thru tandem pump back to "T" on filter. And from filter back to tank. I now have fuel pushed to all these places by cycling the key over and over. Cranks great but no start. AVS is working properly. ( or is it VSA) I believe I have air still somewhere. Does this model have an injection pump?
 

KLXD

Top Post Dawg
Joined
Aug 22, 2009
Location
Lompoc, CA
TDI
'98, '2 Jettas
My understanding is there's the tandem pump on the head (combo fuel/vac), driven by the cam, that supplies high pressure fuel to the injectors which are operated by the cam to cause the actual injection event so no injection pump like the earlier motors.

Did you look at the car won't start thread?
 

gforce1108

Top Post Dawg
Joined
Aug 2, 2006
Location
Newburgh, NY
TDI
04 Jetta GLS BEW, 14 Audi A7 V6 TDI, 13 Porsche Cayenne V6 TDI
No injection pump - 4 mini injector/pumps that are cam driven. I can tell you that when I replaced my tandem pump I could not cycle the air through with the key (nor could I pull through with a vacuum pump). It took quite a bit of cranking to get it fired up.

Make sure the filter housing is filling when you cycle the pump - then, assuming nothing else failed (mice chewing wiring harness), it should eventually start - just don't overheat the started.
 

HappyWagon

Member
Joined
Jan 18, 2018
Location
Ohio
TDI
2005 Jetta
My understanding is there's the tandem pump on the head (combo fuel/vac), driven by the cam, that supplies high pressure fuel to the injectors which are operated by the cam to cause the actual injection event so no injection pump like the earlier motors.

Did you look at the car won't start thread?
Yes I read that thread. That's how I got to where I am. I really like Dan's thread.
 

BobnOH

not-a-mechanic
Joined
May 29, 2004
Location
central Ohio
TDI
New Beetle 2003 manual
Great, I think. So any ideas on this allgy thing?
Usually happens when they sit for a while, like months. Mine did it, I just cleared it with rags, never came back.
I don't know the PD, but can't you just draw fuel thru one of the hoses to the tandem pump? I would think tank to filter it would self bleed.
 
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HappyWagon

Member
Joined
Jan 18, 2018
Location
Ohio
TDI
2005 Jetta
So that's how you spell algae. Thanks for the help. It seems that this algae thing is real then. That's crazy that an organism can live in that fuel. I thought my friend was pulling my chain.
 

AndyBees

Top Post Dawg
Joined
May 27, 2003
Location
Southeast Kentucky
TDI
Silver 2003 Jetta TDI, Silver 2000 Jetta TDI (sold), '84 Vanagon with '02 ALH engine
This is my experience with the PD fuel tanks and pumps. (I'll try to make this short.)

1st - 2004 Jetta, BEW engine, with "bad" lift-pump (leaving out a lot of the story). I took the pump out of the fuel tank. Yes, it was loaded with a black coating (tank, sending unit, and pump). The black stuff is soot. Yes, it may have some algae. However, algae is suspended in the fuel and doesn't coat anything. (I've seen the very fine in-tank strainer in the MK1 diesels totally plugged with slimy black algae (totally different from soot). Algae will not coat the tank.

Anyway, I cleaned up the lift-pump motor and got it working. I had to use a lot of carb cleaner, WD-40, Bolt Buster, etc., to get it working (reversed the current to help break it loose). However, the owner wanted a new pump (leaving out more of the story). IIRC, the lift-pump assembly unit was close to $300.00. Someone on this forum gave me a link for just the pump ($89.XX shipped). Installed and it worked great.

Here is a link to the above incident, short with one photo>
http://forums.tdiclub.com/showthread.php?t=460746

2nd - about two weeks ago, I had to pull the lift-pump unit in another 2004 Jetta, BEW engine, because the guy had put in a couple of gallons of RUG (gasoline). The lift-unit and inside of the tank had the same soot junk. From the engine, with compressed air, I blew out both fuel lines back to the tank. Then, I pumped all the fuel out (left about 1/2 pint) (zero water in this tank). So, I put it all back together, dumped in 5 gallons of diesel fuel, cycled the pump about 5 times, cranked the engine for 15 to 20 seconds and it began to come to life. Remember, the tandem pump (fuel pump and vacuum pump, thus tandem) and everything down stream to the injectors had a gasoline/diesel mix. But, after a few seconds it ran just fine.

Someone on this forum told me about the soot. Apparently, some soot (obviously very, very small amount) gets kicked back from the Injector Tips and flows back with the return fuel. And, I'm sure the filter catches a lot this soot as the fuel is pumped back up again and again! Thus, it probably could be far worse.

I'll try to find my pics and the Thread I started on the first experience and edit. (No Thread on the second experience but I do have pics of the tank.)

Hope this doesn't cause an uproar.
 
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flee

Veteran Member
Joined
Sep 19, 2011
Location
Chatsworth, CA
TDI
2002 Jetta GLS wagon
True story, Andy. The soot will circulate back to the tank and wind up in the filter.
I'm not sure if it is completely normal or a result of wear and tear of the nozzles.
 
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