01 alh nb fuel pump loosing prime help needed

BigVWman

Veteran Member
Joined
Feb 16, 2007
Location
Apex, NC soon to be back in the mitten of doom!
TDI
A1 cabriolet tdi and 01 nb tdi and countless gassers!
Hello everyone, i have an 01 nb alh around 166 on the clock. It has been having an issue lately with loosing its prime. It seems fine if i drive it everyday but if it sets for more than two days it seems to loose it. I can get it going by taking return off and filling pump manually and bleeding etc. I don't see any visible leaks that are obvious. I have changed the return lines, and reclamped the fuel lines to the filter. I even changed the orings on the filter T and still had no luck. Any thoughts what is next? I would think if pump itself needed resealing i would see some wetness on the exterior but i'm open to ideas! Thanks in advance
 

MrSafety

Newbie at Heart
Joined
Jun 27, 2010
Location
California... Novato... 25 Mi. N. of S.F.
TDI
2002 Jetta TDI/ALH/01M-'80 240D Mercedes/'81 Rabbit "Caddy"/'99 Lexus ES300
Hello everyone.
I have an 01 nb ALH around 166 on the clock.
It has been having an issue lately with loosing its prime.
It seems fine if i drive it everyday but if it sets for more than two days it seems to loose it.
I can get it going by taking return off and filling pump manually and bleeding etc.
I don't see any visible leaks that are obvious.
I have changed the return lines, and reclamped the fuel lines to the filter.
I even changed the O-rings on the filter T and still had no luck.
Any thoughts what is next?
I would think if pump itself needed resealing I would see some wetness on the exterior but i'm open to ideas!
Thanks in advance
"BigVWman" -
This malady your car is suffering is one of the most frequent problems I have seen since joining this FORUM...
and I am working on ideas to deal with this...
but first let me ask for some clarification:
Q1 - What do you mean by "nb" above?
Q2 - What specific symptoms do you have that give you reason to say that your engine/IP is "loosing prime?

In passing, let me relate a couple of things I have done to help me deal with this problem:
[a] I installed a see-thru InLine fuel filter in the fuel supply line to the IP...
..... between the fuel filter and the IP. I tried to locate this "sight-glass"
..... at the high point of this line so that I could see the air that would rise
..... to this InLine filter when the engine is shut down... and more important
..... see air passing through when the engine is running.
Using the above filter/sight-glass to watch for air ingestion,
..... have someone hold the throttle at about 2500 RPM(s),
..... you can wiggle fuel line connections and/or rap the main filter and
..... the thermostatic "T" that is inserted into the filter.
[c] I recommend you remove the "Thermostatic-T" from your main filter,
..... carefully remove the two "O-rings",
..... wrap 2 to 4 layers of plumber's "Teflon tape" loosely over the grooves,
..... roll the "O-rings" back over the layers of tape, and
..... carefully trim off the excess Teflon tape from the ends of the O-rings.
MY recommendation for [c] above is because I believe that many (if not most)
of the instances of air ingestion is due to poor QC dimension tolerances
by the often two different manufacturers of the fuel filter and the Thermo-T assembly...
and so the Teflon tape should resolve this.
You might find it very revealing IF you:
(1) install [a],
(2) perform ,
(3) then install [c] and finally
(4) perform again!
A separate thought on how to minimize air ingestion
is to (before you open any of the fuel lines) use some quality (effective)
hose clamps to clamp off the two hoses that come up from the fuel tank...
and do this just before they enter the main fuel filter.
Q3 - What method(s) do you presently use to "prime your fuel filter and IP?
Regards,
Sam Ross
 

BigVWman

Veteran Member
Joined
Feb 16, 2007
Location
Apex, NC soon to be back in the mitten of doom!
TDI
A1 cabriolet tdi and 01 nb tdi and countless gassers!
AGGGHhHHH hoping it wasn't the INj pump seals unless its ones i can change without having to pull pump and retime!
Q1= see above new beetle running gear mostly same as golf or jetta mk4 just vary a littl ein changeover years.
Q2= If car sits for more than a day or two it acts like its out of fuel and pump level seems very low leading to question 3
Q3= I fill the pump through the return with filtered diesel using a large syringe, after it dribbles out crack the injector nuts and crank a few seconds tighten them up and bang she starts right up. I used to use my Vac pump but it sucked some diesel and swelled the rubber now it no longer sucks!
I will give the suggestions a shot, it is really frustrating. I don't currently have a clear fuel line either making diagnosis all the more difficult!
 

chromeBuddha

Veteran Member
Joined
Jun 30, 2006
Location
Arlington, TX - DFW metroplex
TDI
2002 Golf TDI manual
The seals are able to be changed with the pump in the car. If you watch the videos, it should be no problem. Took me about 2 hours for my first one. Watched all the videos first, then would watch 2-3minutes, work on the car 2-3 minutes...= 2 hours total time. Parts cost about $65 shipped from DG, got the QA seal kit, the head seal and the metalnerd special tool. There are some threads on making your own tool, but at $22 it is more an experiment than cost effective to fabricate.
 

MrSafety

Newbie at Heart
Joined
Jun 27, 2010
Location
California... Novato... 25 Mi. N. of S.F.
TDI
2002 Jetta TDI/ALH/01M-'80 240D Mercedes/'81 Rabbit "Caddy"/'99 Lexus ES300
Thanks " chromeBuddha " for pointing out the above for although I just successfully changed out my Son's IP,
I share the reluctance of most on this FORUM to take on the task of first re-adjusting the IP's "static" timing and then also using a VAG-Com system to fine tune the IP's timing!
Luckily for me I have access to a Kent-Moore 3100 [ "K-M" ] black box that allows me to check the "dynamic" timing on all diesels like our VE(s) that have the high-pres heavy steel lines that run to the injectors... unlike the PD(s) and now Common-Rail engines!
With our "K-M", I was able to very "dynamically"/precisely set up our newly installed IP such that when I took it to my trusty VW "INDY",
he found it unbelievable that his VAG-Com system found the IP's timing precisely on!
I still think that some of this was LUCK!
Thanks,
Sam Ross
 
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BigVWman

Veteran Member
Joined
Feb 16, 2007
Location
Apex, NC soon to be back in the mitten of doom!
TDI
A1 cabriolet tdi and 01 nb tdi and countless gassers!
Hello guys! just realized i never finished up this question. I ended up going down the line of possibilities and finally landed on inj pump seals. it wasn't as bad as i feared! it only took a few hours and a few fresh seals and we are leak free now for several weeks!It was the head seal oring that was the culprit i believe! thanks!
 

MrSafety

Newbie at Heart
Joined
Jun 27, 2010
Location
California... Novato... 25 Mi. N. of S.F.
TDI
2002 Jetta TDI/ALH/01M-'80 240D Mercedes/'81 Rabbit "Caddy"/'99 Lexus ES300
Hello guys! just realized i never finished up this question.
I ended up going down the line of possibilities and finally landed on inj pump seals.
It wasn't as bad as I feared!
It only took a few hours and a few fresh seals and we are leak free now for several weeks!
It was the head seal o-ring that was the culprit... I believe!
Thanks!
Thanks "BigVWman" for remembering and for coming back to put finality to your project!
I have One 2-part question...
Q1a - Can you describe what you mean by the "Head Seal O-ring"?...
Q1b - was this simply the round but irregular shaped seal/gasket that
seals the top section of the IP?

"chromeBuddha"
Q2 - Can you shed any light on what he is calling an "Oj-ring"??
=======================
I'd like to take the subject of this short THREAD a slightly
different direction... by asking
Q3 - Can anyone share with us how you would go about detecting
such leaks on the main body of the IP?

Q4 - Is it possible/practicable to spray the outside of the IP
with something that would facilitate finding such leaks?

Q5 - What about putting a dye into the fuel via the filter that
would make it easier to spot such leaks?

Thus far I have limited my curiosity and hands on work on the task
of finding air leaks that are at fittings that are external to the IP...
and mostly at or inbetween the main filter and the IP.
Regards,
Sam Ross
 

BigVWman

Veteran Member
Joined
Feb 16, 2007
Location
Apex, NC soon to be back in the mitten of doom!
TDI
A1 cabriolet tdi and 01 nb tdi and countless gassers!
1a. I was calling the head seal oring, the large diameter oring on the inside where the steel hydraulic head with the 4 pressure valves seals into the aluminum body. The most nervous part for me was worrying about that shim drop, i actually didn't even use the longer bolt offered by DG, i just used one of the two longer bolts that attach it to keep it from coming out too far.
1b. I don't think so, we ended up using a section of tubing and listening to the various joints of the pump after shutdown and could hear a slight bubbling sound almost to the head joint at the pump body. I did change those seals as well since they came in the kit, i wouldn't want to try and reuse them if one rubber seal had failed after that time period i'm sure the rest weren't far behind. The new ones were def more supple than the old ones!
3. Mine wasn't really a fuel leak that i could see at least not a dripping problem i never left any puddles.It made it harder to find. I suspect the former owner may have been running higher concentrations of bio since its fairly popular here in nc, but when i got it my usual station has only regular ulsd and maybe caused a shrinkage issue.
4. I would love to hear about it if someone knows of something, i have several of these and many reg diesels, now and over the years and have never had this issue before but then again the fuels are changing pretty fast lately, advent of various bio fuels and such.
5.I wonder if the dye in off road shows up with a black light or something, if it does, maybe feed the pump off a small tank of off road and look with the black light, kinda like looking for a/c leaks.
 

MrSafety

Newbie at Heart
Joined
Jun 27, 2010
Location
California... Novato... 25 Mi. N. of S.F.
TDI
2002 Jetta TDI/ALH/01M-'80 240D Mercedes/'81 Rabbit "Caddy"/'99 Lexus ES300
Q1a - Can you describe what you mean by the "Head Seal O-ring"?...
Q1b - was this simply the round but irregular shaped seal/gasket that
seals the top section of the IP?

Q2... ( no longer applicable! )
Q3 - Can anyone share with us how you would go about detecting
such leaks on the main body of the IP?

Q4 - Is it possible/practicable to spray the outside of the IP
with something that would facilitate finding such leaks?

Q5 - What about putting a dye into the fuel via the filter that
would make it easier to spot such leaks?

1a. I was calling the head seal oring,
the large diameter O-ring on the inside where the steel hydraulic head
with the 4 pressure valves seals into the aluminum body.
The most nervous part for me was worrying about that shim drop,
I actually didn't even use the longer bolt offered by DG,
I just used one of the two longer bolts that attach it to keep it from coming out too far.
1b. I don't think so,
we ended up using a section of tubing and
listening to the various joints of the pump after shutdown and
could hear a slight bubbling sound almost to the head joint at the pump body.
I did change those seals as well since they came in the kit,
I wouldn't want to try and reuse them if one rubber seal had failed after that time period
i'm sure the rest weren't far behind.
The new ones were def[initely] more supple than the old ones!
3. Mine wasn't really a fuel leak that I could see,
at least not a dripping problem.
I never left any puddles.
It made it harder to find.
I suspect the former owner may have been running higher concentrations
of bio since its fairly popular here in nc,
but when i got it my usual station has only regular ulsd and maybe caused a shrinkage issue.
4. I would love to hear about it if someone knows of something,
I have several of these and many reg diesels,
now and over the years and have never had this issue before
but then again the fuels are changing pretty fast lately,
... [I'm speaking of the] advent of various bio fuels and such.
5. I wonder if the dye in off road shows up with a black light or something,
if it does, maybe feed the pump off a small tank of off road and look with the black light,
kinda like looking for a/c leaks.

Thanks " BigVWman " for your responses to my Q(s)...
(both above to make it easier on the reader!)
Also thanks for expanding upon YOUR the original THREAD subject/title!
First let me explain something...
I am a former military communications officer (USN) who firmly believes that
written dialogue has a far better potential for clarity than verbal dialogue...
but I also realize that not everyone types at my 150 WPM speed (in bursts only)!

Q1 - in your response above to my "[Q3]" what does the abbreviation "ulsd" stand for?
--------------
[3] Expanding upon your response to [Q3], let me say that we should remember that the IP
and certainly the fuel filter and the final delivery/return fuel lines and fittings/connections...
all of these are above the level of the fuel tanks under below the back seat...
and thus there is the potential that a leak could develop where
no fuel leaks out of these elevated components and/or fittings & connections...
but rather what happens only air leaks into these fuel delivery system components
because of the partial vacuum created by the fuel trying to drain back into the tank!
Some such leaks can also leak diesel fuel and create "wetness" that we can detect...
but IMO this should only happen IF the leak location ends up being at or below the level of fuel left in your fuel tank...
and this might not be the case !
===============
[5] So my earlier thought of using dye to detect leaks would not always readily work...
that is unless we use something your comments above just gave me...
unless we temporarily change from supplying the fuel using a partial vacuum...
change to using a positive pressure...
like using an elevated bottle of fuel (with dye) by hanging it off the hood latch...
as I have done for a Diesel Purge apparatus...
my transfusion bottle method!??
Q2 - So what do you think of this leak diagnostic idea
.......that just came to me while composing this POST...
....... a method that should pickup all leaks ??

Regards,
Sam Ross
 
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