How do I prime 2002 beetle tdi?

MMDillon

Member
Joined
Aug 4, 2023
Location
Oregon
TDI
2003 Beetle 1.9L
I’ve tried to find and follow instructions, but I’m missing something, I guess.

SO… my beetle was running ok until the alternator died. Then it sat for a year (for unrelated logistical issues), and I’m trying to repair. I replaced the alternator. BUT…

First, I was warned to check the fuel in case it’s yucky after sitting around in all weather. Tried to pull out the in-tank fuel pump to look, but the darn lock ring was TIGHT and I didn’t want to break anything. So I unplugged the lines in & out of the pump and I jammed the hose of a little manual hand pump into them to suck a bit of fuel to see.

That worked, and people who know diesel better said the fuel looks OK. I changed the main fuel filter though because I don’t know how old it is, and filled the filter with a diesel boost/fuel mix. My fuel level is just under 1/2 a tank by the way.

it cranks but won’t start. Fuel isn’t getting to the engine? It was only THEN that I learned that the fuel lines are a closed pressure system. Oops. So when I sucked some fuel from the blue line that goes into the pump, I thought that was coming from the tank, but it’s the line back from the engine. OH.

So then I figured I’d really better look in the tank. I managed to get the ring unscrewed after all, and I pulled out the in-tank fuel pump. It’s a tiny bit dirty, but I can’t tell if it’s ok or not. With a good light shining into the tank, it looks clear in there. Only a few little specks of dirt. The fuel is not cloudy or gummy.

So perhaps my problem is indeed the air gaps in the fuel lines, which I KNOW I caused earlier with my little hand pump.

How do I properly make sure the air is burped out and the lines and injector pump are primed?
 

mittzlepick

Veteran Member
Joined
Mar 18, 2001
Location
union maine
TDI
2004 jetta wagon (365k)2001 wagon tire burner 6spd 2003 wagon(417k)
If it's an 04 05 the intake pump will prime it. If it's older there is no In tank pump. Either way pull the return hose and vacuum pump till there's fuel being pulled. City vac or oil extractor pump which is better
 

MMDillon

Member
Joined
Aug 4, 2023
Location
Oregon
TDI
2003 Beetle 1.9L
If it's an 04 05 the intake pump will prime it. If it's older there is no In tank pump. Either way pull the return hose and vacuum pump till there's fuel being pulled. City vac or oil extractor pump which is better
I’m slightly confused. I’ve got a 2002 1.9 cc tdi. When I say in-tank fuel pump, I mean that fuel pump under the back seat, that sits in the fuel tank.

So are you saying I should have everything hooked up and ready, keep the engine off and the key in my pocket, pull the blue return-from-engine line off the pump that’s back there under the seat, and suck fuel from there to remove the air from the lines? Pulling fuel from the tank through the pump through the out line, through the fuel filter, through the injector pump, through the return line? (Hopefully removing any air bubbles in that whole circuit.)

If so, how do I know I’ve gotten all the air out, if there are air bubbles in more than one spot in that circuit?

and what’s the vacuum tool you’re mentioning?

Thanks. I’m very noob still.
 

turbodieseldyke

Top Post Dawg
Joined
Jun 6, 2010
Location
Free Mustache Rides
TDI
98 jetta
I’ve got a 2002 1.9 cc tdi. When I say in-tank fuel pump, I mean that fuel pump under the back seat, that sits in the fuel tank.
Your car doesnt have a pump back there, unless someone added it. The injection pump on the engine sucks fuel up from the tank.

The vacuum tool they're referring to is probably a little handheld one. I've used an A/C vacuum when i had lots of fuel to pull up the lines.
 

MMDillon

Member
Joined
Aug 4, 2023
Location
Oregon
TDI
2003 Beetle 1.9L
or do the old crack the injectors til you get spray one by one...
Under what conditions should I try to slightly loosen the injectors? While the engine is off, I assume? :) Of course it hasn’t started since the last battery ran down enough to not start it, although since I’ve cranked the starter, I presume the fuel pump and IP tried to send fuel to the engine… I just don’t know if it did. So if I go crack the injectors loose one by one, and they all spit out a little fuel spray, that gets the air out?

Since I haven’t tried starting after pulling out the fuel pump to look at it, should I try starting it for a few seconds again before cracking the injectors, since I presume I just put more air bubble in the blue and black lines when unplugging them?

Or is that a terrible idea for some reason? I know very little apparently. :)
 

Vince Waldon

Top Post Dawg
Joined
Apr 25, 2009
Location
Edmonton AB Canada
TDI
2001 ALH Jetta, 2003 ALH Wagon, 2005 BEW Wagon
I’m slightly confused. I’ve got a 2002 1.9 cc tdi. When I say in-tank fuel pump, I mean that fuel pump under the back seat, that sits in the fuel tank.
On your version of the engine (known as an ALH) the injection pump includes an internal lift pump; there's no lift pump in the fuel tank itself, just the level sensor for the fuel gauge on the dash. Just two wires, right?
 

MMDillon

Member
Joined
Aug 4, 2023
Location
Oregon
TDI
2003 Beetle 1.9L
Your car doesnt have a pump back there, unless someone added it. The injection pump on the engine sucks fuel up from the tank.

The vacuum tool they're referring to is probably a little handheld one. I've used an A/C vacuum when i had lots of fuel to pull up the lines.
Now I’m more confused. If it doesn’t have a fuel pump in the fuel tank, that you access through a hatch under the back seat, then what’s this thing?

http://instagr.am/p/C93ikfTP7xO/
 

MMDillon

Member
Joined
Aug 4, 2023
Location
Oregon
TDI
2003 Beetle 1.9L
On your version of the engine (known as an ALH) the injection pump includes an internal lift pump; there's no lift pump in the fuel tank itself, just the level sensor for the fuel gauge on the dash. Just two wires, right?
The electrical plug (that plugs into the thing I thought was the second fuel pump) has just two wires, yes.

I read that it was a low-pressure fuel pump that sends fuel up to the injector pump on the engine. But I’m piecing together information from different threads and videos, so I’m not sure what I’m right or wrong about lol.

So that whole coffee-can-sized plastic thingy is just the fuel level sensor assembly?
 

Vince Waldon

Top Post Dawg
Joined
Apr 25, 2009
Location
Edmonton AB Canada
TDI
2001 ALH Jetta, 2003 ALH Wagon, 2005 BEW Wagon
Yes, just the level sensor.

The engine that came out a couple years later (the BEW) has no injection pump per se, and does have an in-tank lift pump.

When looking at TDI threads/videos it can be a little confusing and you kinda have to keep track of which engine model they are referring to... the car looks the same but the engine designs have significant differences.

One note: as the ALH (your model) IP wears the internal lift pump can weaken and become more likely to not self-prime if run dry... priming by pulling a vacuum with a vacuum pump at the return line is the common way to make things right again. Also important to pre-fill the new fuel filter, when doing a fuel filter change.
 
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MMDillon

Member
Joined
Aug 4, 2023
Location
Oregon
TDI
2003 Beetle 1.9L
Yes, just the level sensor.

The engine that came out a couple years later (the BEW) has no injection pump per se, and does have an in-tank lift pump.

When looking at TDI threads/videos it can be a little confusing and you kinda have to keep track of which engine model they are referring to... the car looks the same but the engine designs have significant differences.

One note: as the ALH (your model) IP wears the internal lift pump can weaken and become more likely to not self-prime if run dry... priming by pulling a vacuum with a vacuum pump at the return line is the common way to make things right again. Also important to pre-fill the new fuel filter, when doing a fuel filter change.
My gosh, thank you. XD

But yeah the real question now is how to get the prime done. I’ve read different things about at which point in the loop to suck fuel. I didn’t think sucking it from all the way at the return end would work.

And… since the only vacuum I’ve used is a Dustbuster… what kind of vacuum too are we talking about? Special little one just for this kind of thing, or just a wet/dry shop vac with a little adapter or…?
 

CanadianALH

Veteran Member
Joined
Aug 21, 2023
Location
Canada
TDI
2002 Jetta 5spd 2006 Jetta DSG (wifes)
My gosh, thank you. XD

But yeah the real question now is how to get the prime done. I’ve read different things about at which point in the loop to suck fuel. I didn’t think sucking it from all the way at the return end would work.

And… since the only vacuum I’ve used is a Dustbuster… what kind of vacuum too are we talking about? Special little one just for this kind of thing, or just a wet/dry shop vac with a little adapter or…?
A vacuum pump. Just a little hand held thing that will pull a little air. Look up mini vac it has a gauge and such. The best way to bleed the system is to crack and injector nut while someone cranks the car making sure you wrap a rag around the line so the fuel being sprayed doesn’t make a mess. I have done this before and it works well.
 

MMDillon

Member
Joined
Aug 4, 2023
Location
Oregon
TDI
2003 Beetle 1.9L
My gosh, thank you. XD

But yeah the real question now is how to get the prime done. I’ve read different things about at which point in the loop to suck fuel. I didn’t think sucking it from all the way at the return end would work.

And… since the only vacuum I’ve used is a Dustbuster… what kind of vacuum too are we talking about? Special little one just for this kind of thing, or just a wet/dry shop vac with a little adapter or…?
BTW the link below is the cheap little Harbor Freight hand pump I already have, which I used in the first place … and I used it on the blue return line, when trying to look at the fuel.

Hmm, although when I used it before, I did have BOTH the lines unplugged, so I think I simply sucked all the fuel from the circuit and the whole thing is air. I think I figured out the problem?
O_O

I’ll try keeping the black line plugged in, and suck from the blue line and see if I can get fuel all the way through. It might work…

 

Vince Waldon

Top Post Dawg
Joined
Apr 25, 2009
Location
Edmonton AB Canada
TDI
2001 ALH Jetta, 2003 ALH Wagon, 2005 BEW Wagon
Yup, that may work... it's certainly the right idea.

And yup, leave the intake line connected. The idea is to draw fuel all the way thru the sender... to the filter... thru the filter to the injection pump...and then fill the injection pump.
 

Brett San Diego

Veteran Member
Joined
Jun 25, 2013
Location
San Diego
TDI
02 Jetta wagon manual
Here's a typical priming set up. Leave all your fuel hoses hooked up. Pull a vacuum on the fuel injector return hose using a hand vacuum pump (Mity-Vac) with a reservoir in between the injection pump and the vacuum pump to catch the fuel. I laid down the white towel just for visibility for the picture (although it's not a bad idea to put down a towel to catch any stray diesel).

Brett
 

PakProtector

Veteran Member
Joined
Jan 5, 2014
Location
AnnArbor, MI
TDI
Mk.4's and the Cummins
So far, all my ALH's have been a PITA to prime. Sooo, with a rig like Brett's, I suck on the line from the pump that attaches to the T on the filter. The catch can is available with some of those hand sucker kits. If fuel does not come freely and quickly I pull a vacuum and then hit the key. Once I have fuel coming out the pump, either it starts quickly, or I loosen some of the 17mm nuts on the injector lines( at the injector ). Nut loosening *AFTER I put the fuel line back onto the filter's T fitting. Once finished with it running, then the clamp can go on...

Douglas
 

Zak99b5

Veteran Member
Joined
Apr 30, 2021
Location
Albany NY
TDI
2003 Jetta TDI
When I swapped out my IP, I primed it by removing the banjo fitting for the return on the pump and applied vacuum there with my mity vac until it was full of fuel.

Then, after reattaching the banjo, I loosened all four injector nuts and cranked the motor over until there was fuel at each one.

Tightened the injector nuts, and it started up with little drama.

I’ve read here that there’s a check valve in the return, and if you put vac on the return line that goes to the filter it’s much harder to prime the pump.
 

BobnOH

not-a-mechanic
Joined
May 29, 2004
Location
central Ohio
TDI
New Beetle 2003 manual
I prime the pump if needed, by attaching a long clear hose to the IP out port. Then suck and pinch until I get solid fuel. Then crack all 4 injector nuts half to 3 quarter turn, put down some rags and crank until you get spray.
 

MMDillon

Member
Joined
Aug 4, 2023
Location
Oregon
TDI
2003 Beetle 1.9L
When I swapped out my IP, I primed it by removing the banjo fitting for the return on the pump and applied vacuum there with my mity vac until it was full of fuel.

Then, after reattaching the banjo, I loosened all four injector nuts and cranked the motor over until there was fuel at each one.

Tightened the injector nuts, and it started up with little drama.

I’ve read here that there’s a check valve in the return, and if you put vac on the return line that goes to the filter it’s much harder to prime the pump.

Hmmm. The banjo fitting is the small 45-degree pipe pointing back to the filter, and the hollow nut attaching it?

I could not get fuel from the end of that pipe with my hand pump.

Before that, I tried pulling fuel straight from the blue return line, but the plastic intake hose of my hand pump flattened in vacuum with no fuel coming out. (The black out-of-tank-to-engine line was attached where it goes).

Then I attached my pump to the exit spout if the (new) fuel filter, and I DID get fuel to pump out, so fuel goes from the tank through the filter OK…

Then (as I said) I tried attaching my pump to the little pipe from the injector pump that goes back to the T intersection in the top of the filter, to see if it pulls from filter through injector pump. My hand pump intake tube flattened with vacuum.

SO I can’t pull fuel through the injector pump, at least not that way. Does this mean the injector pump is clogged? (It wasn’t apparently clogged before I parked it for a year, bc what stopped it was the dying alternator, but maybe debris settled, idk.)

What should I try checking about the injector pump? I don’t want to try starting it again yet until I understand more.

OH the T intersection that plugs into the top of the filter is the check valve, right? Anyway, if that was all that was interfering with me trying to pull fuel from the blue return line, I should have been babble to pull fuel from the injector pump return spout (or whatever).

When you say you removed the banjo fitting, do you mean you removed that pipe from the injector pump and hand-pumped fuel from the hole it came out of?

ty
 
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Zak99b5

Veteran Member
Joined
Apr 30, 2021
Location
Albany NY
TDI
2003 Jetta TDI
When you say you removed the banjo fitting, do you mean you removed that pipe from the injector pump and hand-pumped fuel from the hole it came out of?

ty
yes. You remove the banjo bolt and that 'turn back' pipe. I think the check valve is in that, but I don’t know. But apply vac to that hole. First time I tried it, it didn’t work. Then I realized I had the injector nuts loosened so I was just sucking air from them. Tightened them down, and didn’t take long to fill the pump with fuel.
 

MMDillon

Member
Joined
Aug 4, 2023
Location
Oregon
TDI
2003 Beetle 1.9L
IT WORKED! Yes,it looks like there’s a check valve built into the banjo bolt. I removed it (and the turn back pipe that’s on it), and jammed my hand-pump tube into the hole (it’s just the right size; I actually screwed the hose directly into the hole threads).

sucked a little, the hand pump drew fuel, carefully pulled it off and reattached the bolt/pipe/hose/etc that’s supposed to be there…

Car started up just fine.
HURRAH!

I’m posting this in case someone some day follows the convo and wants to know. :D
 

Brett San Diego

Veteran Member
Joined
Jun 25, 2013
Location
San Diego
TDI
02 Jetta wagon manual
For what's it worth, I've never had a problem pulling a vacuum on the injector return line. On one ALH, the fuel pull was slow and it took a few minutes to have fuel flowing out of the line. On another, the flow was pretty fast and took little time to fill the pump. No need to unbolt any sealed fittings.

Brett
 

MMDillon

Member
Joined
Aug 4, 2023
Location
Oregon
TDI
2003 Beetle 1.9L
For what's it worth, I've never had a problem pulling a vacuum on the injector return line. On one ALH, the fuel pull was slow and it took a few minutes to have fuel flowing out of the line. On another, the flow was pretty fast and took little time to fill the pump. No need to unbolt any sealed fittings.

Brett
Yeah, that’s what I expected, but (oddly?) pulling from that return pipe pulled NOTHING.

I took it off and saw the banjo bolt isn’t simply hollow; there’s some little metal cylinder attached inside it as part of it. IDK if it’s literally a valve but it’s something there on purpose. :)

Pulled from the pump from the banjo hole with the banjo removed, and it pulled fuel. Put the banjo back on and then as a test tried pulling from the return pipe again, and STILL NOTHING. But it started this time.

So it definitely seems as though whatever structure is inside the banjo fitting makes it so the pump can push fuel out through the banjo, but I can’t PULL fuel out through the banjo.

Shrug. 🤷🏻‍♂️

it works now.
 

Brett San Diego

Veteran Member
Joined
Jun 25, 2013
Location
San Diego
TDI
02 Jetta wagon manual
Yeah, that’s what I expected, but (oddly?) pulling from that return pipe pulled NOTHING.

I took it off and saw the banjo bolt isn’t simply hollow; there’s some little metal cylinder attached inside it as part of it. IDK if it’s literally a valve but it’s something there on purpose. :)

Pulled from the pump from the banjo hole with the banjo removed, and it pulled fuel. Put the banjo back on and then as a test tried pulling from the return pipe again, and STILL NOTHING. But it started this time.

So it definitely seems as though whatever structure is inside the banjo fitting makes it so the pump can push fuel out through the banjo, but I can’t PULL fuel out through the banjo.

Shrug. 🤷🏻‍♂️

it works now.
Pulling a vacuum on the injector return line is a reverse flow situation. Maybe that is a check valve meant to prevent this reverse flow...

On my daily driver, I left it under vacuum for 10 min or so, and fuel finally filled the pump, and then there was a very slow but constant flow out of the injector return line. On a 2003 project car, it pulled fuel quite fast out of the injector return line. If that is a check valve, maybe it's just not functioning well on my 2003.

Good info you provided. Thanks for posting the resolution. I hate it when threads trail off without the OP coming back and posting a resolution.

Brett
 
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