'03 ALH Jetta, 5Sp, Power loss/engine cut out climbing hills, P0252 code (Fuel Starvation)

mrGutWrench

Top Post Dawg
Joined
Aug 29, 2002
Location
Carrboro, NC
TDI
'03 Jetta Wagon, 5-speed, 563K Miles (July '23)
'03 ALH, 557,000 miles. I was having intermittent power reductions on the road, about once a week for 4 weeks - OK at 75 Mph cruise but stumbling on hills. Despite the intermittent symptoms, it was running fine, good mileage (about 52 Mpg/tank), easy starts. Then a couple of weeks ago, I went on a trip through the NC mountains. The first hill I came to, it threw a P0252 code and went to severe limp mode. Driving on shoulder in second and not exceeding 7.5 Psi boost, I got up that hill in about 15 minutes. From then on, It would cut out at any speed over 55 Mph and hill-climbing was the stuff of nightmares. Sometimes, it would just stumble and turn on the PO252 code (on Scan-Gauge) and go to limp mode. A couple of times, it cut out entirely and I had to bleed injectors but there was very little bubbling in the clear fuel pump line, and fuel came out of the injector fittings quickly -- then it would start easily. It seemed that either cooling down or letting the residual vacuum from the FI pump pull fuel up from the tank.
I got it home and started looking at fuel starvation There was nothing but clean fuel in the fuel filter but I changed it anyway (apparently the fllter was full of fuel at that time). I put my oil evacuator pump on the fuel feed line from the tank at the filter -- that pumps empties the engine in 30 seconds, so I know it really move fluids. It would pull a couple of ounces of fuel and then sputter and and not pull for 5 - 10 seconds, then spit a few ounces and the flow would stop for 5 -10 seconds. After about a minute there was less than half a quart of fuel in the catch bottle.
I took the fuel feed line off the "fuel level unit" (which is the fuel pickup on an ALH, no fuel pump just the fuel pickup is part of this assembly. The fuel pipe from the pickup to the under-hood filter was free and clear.
Next step was to remove the fuel level unit. It was impossible to pull air through the pickup fitting. It's just a rigid plastic tube with a sliding "telescope" extension at the bottom and a coarse strainer which seems molded into the tube. The strainer was blocked with black flakes. There's also a cup-type device on the bottom of the level unit that slides along with the telescoping part of the pick up. There was some black particle-type trash in the bottom of the cup but not a lot.
The unit itself is covered with a very thin coat of a light brown slime (but how do you differentiate between diesel fuel "oiliness" and contaminants??). I don't think that it's been removed or changed in 557,000 miles so who knows what's been through it in that time.

(History - about 8 months ago, I was going to a place that has always had good quality fuel at a good price but I was running low and I ducked into a nasty-looking truck stop. I splashed in 2 gallons to get me 50 miles to the preferred station. I pulled out on the Interstate and within 15 miles, I passed two big trucks running 15 Mph on the shoulder with smoke pouring out of their stacks. Then I passed a truck on the side of the road with the hood open and a mechanic (or driver) replacing a fuel filter, and in 10 miles another one exactly the same. As I pulled into the preferred station, my engine quit so I coasted up to the pumps. After I filled with fresh fuel, it wouldn't start -- no sign of life just like fuel starvation but I knew that I had enough to safely get there. I pushed over to the parking area, put in a new filter, primed it with Power-Service, cracked open an injector, and on the second starter cycle (10 seconds, then 1 minute cool-off), fuel was bubbling, so I tightened up the injector, it started and ran fine. But I always wondered why I had a fuel starvation problem -- and a few trucks within 50 miles of that place -- just after I put a little fuel in my car from an unknown source. In the months since then, I'd noticed very slight signs of fuel starvation, including random PO252 codes and I wondered if there was a bigger problem looming. Now I find out that there was.)

Since I haven't had a car payment in 19 years, I figured I'd invest a little in my '03 wagon so I ordered a new level unit from IDParts, with some new fuel line clips, etc. That should solve the immediate problem. (I know I could have flushed the strainer etc. or even drilled it out -- I drilled my '02 when it was showing signs of fuel blockage in cold weather about 2004, but I was worried about plastic chips and it just seemed best to start with new parts.)

MY BIGGEST QUESTION AT THIS STAGE -- So, now, before I put the new level unit in, I was wondering if I should treat the tank for algae. I don't really have fuel storage or disposal capability -- and of course, since my car ran better and showed fewer symptoms with a full tank, I had just filled it before I began this work -- so I'd like to avoid emptying and cleaning the tank, but I expect it would be the right thing to do. My first plan was to inspect the tank, pull a bit of fuel out of the bottom of the tank with my vacuum pump to inspect for debris, and put anti-algae in the tank but after I do do that, would it just clog filters and cause trouble with dead algae, if I don't empty and clean the tank? (Of course, new under-hood fuel filter, filter prime and clear-fuel pipe prime, new sealing clips, new thermo-T and O-rings, etc.)

I really want this repair to be a reliable and complete repair so I can get my car back on the road. I'd appreciate any comments and suggestions. Thank you, Mr G

03 Jetta Wagon, ALH TDI 1.9L, 5-speed, 557,000 miles. Timing belt done approx. 5K ago by a trusted shop.
 

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis, MO
TDI
There are just too many to list....
Sounds to me like your injection pump needs to be rebuilt or replaced. N108 is inside the pump.

While that is not a common thing, I've seen plenty of ALHs over the years have all kinds of fuel starvation problems from bad fuel, severely neglected fuel filters, etc. but they never set any DTCs.

Every time I think I won't see another ALH with its original intact pump, another one comes in that needs one gone through. I have a few here right now, and I think all three of them combined have not covered the mileage yours has, so you did good. That pump owes you nothing. DFIS will make it like new again.
 

mrGutWrench

Top Post Dawg
Joined
Aug 29, 2002
Location
Carrboro, NC
TDI
'03 Jetta Wagon, 5-speed, 563K Miles (July '23)
Sounds to me like your injection pump needs to be rebuilt or replaced. N108 is inside the pump.

While that is not a common thing, I've seen plenty of ALHs over the years have all kinds of fuel starvation problems from bad fuel, severely neglected fuel filters, etc. but they never set any DTCs.

Every time I think I won't see another ALH with its original intact pump, another one comes in that needs one gone through. I have a few here right now, and I think all three of them combined have not covered the mileage yours has, so you did good. That pump owes you nothing. DFIS will make it like new again.
Thanks. I have always had in my mind that there was a good chance that the pump was toast. I've always been aware that no matter how sure you are that you've solved a big, obvious problem, you have to be sure that that was the *only* problem. The fuel pickup in the tank was about as solidly blocked as it's possible for a plastic tube to be and that's easily fixed. Being in my 70s, I have never felt that I could reasonably take on the physical job of changing a timing belt so I don't have timing tools to remove and reinstall the pump myself.

Oilhammer, if you were going to replace a pump on an ALH 5-speed, would you go to the 11mm injector pump -- I suppose that it might be difficult to find one without an 11mm core, so I suppose that the most cost effective way would be to have my existing pump rebuilt. Thoughts?

Thanks, Mr, G
 

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis, MO
TDI
There are just too many to list....
We send all our pumps to DFIS, I have one there now.

You can call and ask them if they have an 11mm pump core for you, or at least the 11mm pump head. They may still even be available new (the head).
 

BobnOH

not-a-mechanic
Joined
May 29, 2004
Location
central Ohio
TDI
New Beetle 2003 manual
DFIS is pricey (+/- $1000), but you'll end up with a better-than-new injection pump. For me, not worth messing with used pumps, my own rebuild or discount parts. If I'm reading accurately, your pump has 550k miles, it don't owe you nothing.
 

jettawreck

Top Post Dawg
Joined
Aug 2, 2004
Location
Northern Minnesota-55744
TDI
2001 Jetta and 2003 Jetta
I only read/follow a few of the forum sections these days but it's been a long time since I've seen mrGutWrench. Nice to see a long term name again.
Last summer I had my fuel tank pickup assembly crack around the supply tube nipple. It was almost impossible to see. Car (2003 Jetta that I converted/swapped from gas to TDI) ran fine when I left home and wouldn't start when I came out of the hardware store. Bled system in the parking lot and when it finally started it drove home (lots of bubbles in fuel line), no start after shut down. About drove me crazy finding the air leak.
Swapped the pickup assembly with my 2001 and problem solved while the JB Weld cured up around the crack on the top cover around the outlet nipple.
Hope the new pickup assembly fixes your issue and won't have to have the IP rebuilt (yet). Congrats on the mileage accumulated so far.
 

mrGutWrench

Top Post Dawg
Joined
Aug 29, 2002
Location
Carrboro, NC
TDI
'03 Jetta Wagon, 5-speed, 563K Miles (July '23)
I only read/follow a few of the forum sections these days but it's been a long time since I've seen mrGutWrench. Nice to see a long term name again.
Last summer I had my fuel tank pickup assembly crack around the supply tube nipple. It was almost impossible to see. Car (2003 Jetta that I converted/swapped from gas to TDI) ran fine when I left home and wouldn't start when I came out of the hardware store. Bled system in the parking lot and when it finally started it drove home (lots of bubbles in fuel line), no start after shut down. About drove me crazy finding the air leak.
Swapped the pickup assembly with my 2001 and problem solved while the JB Weld cured up around the crack on the top cover around the outlet nipple.
Hope the new pickup assembly fixes your issue and won't have to have the IP rebuilt (yet). Congrats on the mileage accumulated so far.
Thanks, JW. Life is been a little busy for me lately but the Jetta Wagon has served me well. About 5 years ago. I got married for the first time (age 69) to a Minnesota transplant to NC and - being married to a Minnesota Viking Warrior Queen - I don't have much time on my hands.
Thanks for the kind words. We're doing a couple of short vacations, just got back from one and going again this weekend, so work on the car will go slowly right now but I'm looking forward to tracking all this down.
I did a little summary a few years ago. As I figured it; comparing TDI mileage to a comparable gasser, factoring in for diesel being a little more expensive than gas since about 2006, doing my maintenance (except timing belts), etc.), I saved enough on fuel when I reached about 375,000 miles to pay me back the $20K initial cost of my first TDI. So, VW gave me a free car for about 20 years (so far) and I don't mind investing a bit in it. I just hope that I can get my trust in its reliability back -- I'm too old to be standing on the side of the road trying to figure out what's next!

Thanks for the kind words, best wishes for good times, good health, and good TDI'ing!
 

mrGutWrench

Top Post Dawg
Joined
Aug 29, 2002
Location
Carrboro, NC
TDI
'03 Jetta Wagon, 5-speed, 563K Miles (July '23)
Hi, JW. You were saying that you found a little crack in the fuel pickup assy? I didn't know that VW had fiddly little parts that can fail and spoil your whole day ... or week!

VW is back running again. It took two 10 second cranks to bleed the injectors (the fuel injector pump and all the lines must have been DRY!). Now to refill the fuel tank with algaecide treated fuel. Then a full-speed test drive.
Thanks for the info and encouragement. Best wishes, MrG.
 
Last edited:

jettawreck

Top Post Dawg
Joined
Aug 2, 2004
Location
Northern Minnesota-55744
TDI
2001 Jetta and 2003 Jetta
Great news when it's a simple inexpensive fix!!
Mine was sort of self inflicted. The 2003 gasser chassis that I swapped the TDI into from the one that was rear ended had the pickup crack because I left the gas lines and attached filter assembly in place and the fuel line(s) were slightly shorter than the diesel setup, so it stressed the nipple and cracked the base ever so slightly. I really should change those short lines and remove the gasser fuel pre-filter (mounted next to the fuel tank) to prevent a recurrence.
 

mrGutWrench

Top Post Dawg
Joined
Aug 29, 2002
Location
Carrboro, NC
TDI
'03 Jetta Wagon, 5-speed, 563K Miles (July '23)
Great news when it's a simple inexpensive fix!!
Mine was sort of self inflicted. (snip)
Thanks for that info. Just because I could, I took a look at the connector nipples on my fuel pickup assembly and they were OK, after 557K. But the pickup tube strainer was badly clogged (I couldn't pull fuel through it with my oil change pump) and then I found the broken Thermo-T.
Another illustration of a lesson that I had to learn the hard way. "You have a problem and you find something wrong -- Never assume that fixing that one thing has really solved all your problem."
 

mrGutWrench

Top Post Dawg
Joined
Aug 29, 2002
Location
Carrboro, NC
TDI
'03 Jetta Wagon, 5-speed, 563K Miles (July '23)
Sounds to me like your injection pump needs to be rebuilt or replaced. N108 is inside the pump.

While that is not a common thing, I've seen plenty of ALHs over the years have all kinds of fuel starvation problems from bad fuel, severely neglected fuel filters, etc. but they never set any DTCs.

Every time I think I won't see another ALH with its original intact pump, another one comes in that needs one gone through. I have a few here right now, and I think all three of them combined have not covered the mileage yours has, so you did good. That pump owes you nothing. DFIS will make it like new again.
I drove about 20 miles today. I had the first start yesterday after the new fuel pickup assembly and also a new thermo-T. It took a good bit of bleeding the injectors but it roared to life smoothly once it caught. This was Tuesday PM - I drove it about 3 miles on town streets and it was impeccable. Then today I drove it to run errands and did about 20 miles; with traffic lights, fairly heavy traffic (college town, kids coming back), and about 4 stops, all restarts quick, easy and smooth. I was mostly on 45 Mph streets and roads (or slower) so there was little chance to really get into it but I did a couple of stop light to stop light sprints to 4500 in 2nd and 3rd and it never showed any sign of a problem. No CEL, no codes (via Scan Gauge).

I'm assuming I'm going to need a pump soon but for right now, it seems to be running perfectly. Thanks for the help. Mr G
 

mrGutWrench

Top Post Dawg
Joined
Aug 29, 2002
Location
Carrboro, NC
TDI
'03 Jetta Wagon, 5-speed, 563K Miles (July '23)
Just after I wrote that post above, the Missus and I took off for a late-summer vacation. I got home about a week ago. Since then, I finished up a little clean-up work that I had to leave when we were on vacation and I've driven my TDI about 200 miles around town plus a 90-mile one-way round trip last Sunday. Every start was quick and easy - even after sitting in the garage for about 4 weeks - the engine never missed a beat and it's run sweet as coconut pie. I've continued to give it full accelerator when going up a hill at moderate speed (pulling up to 16 - 18 on the Scan Gauge boost reading when it would immediately go into limp mode at 6.5 to 7 before), it has not triggered any DTCs or limp modes since I changed the filter, the thermo-T, and the fuel pickup. I'm going to do that 180-mile round trip again tomorrow but I don't anticipate any issues. I'm going to continue to work on sourcing a replacement fuel pump (at 559K miles, the one on it owes me nothing!) but it appears that it will be fine until I can get that pump changed (no tools to do it myself).
Thanks for the info you've given me here, I'm hoping that I'll be 100% back in TDI-land again soon. Mr. G.
 

tripLr

Member
Joined
May 9, 2021
Location
Wa. State, USA
TDI
2002 Golf
'03 ALH, 557,000 miles. I was having intermittent power reductions on the road, about once a week for 4 weeks - OK at 75 Mph cruise but stumbling on hills. Despite the intermittent symptoms, it was running fine, good mileage (about 52 Mpg/tank), easy starts. Then a couple of weeks ago, I went on a trip through the NC mountains. The first hill I came to, it threw a P0252 code and went to severe limp mode. Driving on shoulder in second and not exceeding 7.5 Psi boost, I got up that hill in about 15 minutes. From then on, It would cut out at any speed over 55 Mph and hill-climbing was the stuff of nightmares. Sometimes, it would just stumble and turn on the PO252 code (on Scan-Gauge) and go to limp mode. A couple of times, it cut out entirely and I had to bleed injectors but there was very little bubbling in the clear fuel pump line, and fuel came out of the injector fittings quickly -- then it would start easily. It seemed that either cooling down or letting the residual vacuum from the FI pump pull fuel up from the tank.
I got it home and started looking at fuel starvation There was nothing but clean fuel in the fuel filter but I changed it anyway (apparently the fllter was full of fuel at that time). I put my oil evacuator pump on the fuel feed line from the tank at the filter -- that pumps empties the engine in 30 seconds, so I know it really move fluids. It would pull a couple of ounces of fuel and then sputter and and not pull for 5 - 10 seconds, then spit a few ounces and the flow would stop for 5 -10 seconds. After about a minute there was less than half a quart of fuel in the catch bottle.
I took the fuel feed line off the "fuel level unit" (which is the fuel pickup on an ALH, no fuel pump just the fuel pickup is part of this assembly. The fuel pipe from the pickup to the under-hood filter was free and clear.
Next step was to remove the fuel level unit. It was impossible to pull air through the pickup fitting. It's just a rigid plastic tube with a sliding "telescope" extension at the bottom and a coarse strainer which seems molded into the tube. The strainer was blocked with black flakes. There's also a cup-type device on the bottom of the level unit that slides along with the telescoping part of the pick up. There was some black particle-type trash in the bottom of the cup but not a lot.
The unit itself is covered with a very thin coat of a light brown slime (but how do you differentiate between diesel fuel "oiliness" and contaminants??). I don't think that it's been removed or changed in 557,000 miles so who knows what's been through it in that time.

(History - about 8 months ago, I was going to a place that has always had good quality fuel at a good price but I was running low and I ducked into a nasty-looking truck stop. I splashed in 2 gallons to get me 50 miles to the preferred station. I pulled out on the Interstate and within 15 miles, I passed two big trucks running 15 Mph on the shoulder with smoke pouring out of their stacks. Then I passed a truck on the side of the road with the hood open and a mechanic (or driver) replacing a fuel filter, and in 10 miles another one exactly the same. As I pulled into the preferred station, my engine quit so I coasted up to the pumps. After I filled with fresh fuel, it wouldn't start -- no sign of life just like fuel starvation but I knew that I had enough to safely get there. I pushed over to the parking area, put in a new filter, primed it with Power-Service, cracked open an injector, and on the second starter cycle (10 seconds, then 1 minute cool-off), fuel was bubbling, so I tightened up the injector, it started and ran fine. But I always wondered why I had a fuel starvation problem -- and a few trucks within 50 miles of that place -- just after I put a little fuel in my car from an unknown source. In the months since then, I'd noticed very slight signs of fuel starvation, including random PO252 codes and I wondered if there was a bigger problem looming. Now I find out that there was.)

Since I haven't had a car payment in 19 years, I figured I'd invest a little in my '03 wagon so I ordered a new level unit from IDParts, with some new fuel line clips, etc. That should solve the immediate problem. (I know I could have flushed the strainer etc. or even drilled it out -- I drilled my '02 when it was showing signs of fuel blockage in cold weather about 2004, but I was worried about plastic chips and it just seemed best to start with new parts.)

MY BIGGEST QUESTION AT THIS STAGE -- So, now, before I put the new level unit in, I was wondering if I should treat the tank for algae. I don't really have fuel storage or disposal capability -- and of course, since my car ran better and showed fewer symptoms with a full tank, I had just filled it before I began this work -- so I'd like to avoid emptying and cleaning the tank, but I expect it would be the right thing to do. My first plan was to inspect the tank, pull a bit of fuel out of the bottom of the tank with my vacuum pump to inspect for debris, and put anti-algae in the tank but after I do do that, would it just clog filters and cause trouble with dead algae, if I don't empty and clean the tank? (Of course, new under-hood fuel filter, filter prime and clear-fuel pipe prime, new sealing clips, new thermo-T and O-rings, etc.)

I really want this repair to be a reliable and complete repair so I can get my car back on the road. I'd appreciate any comments and suggestions. Thank you, Mr G

03 Jetta Wagon, ALH TDI 1.9L, 5-speed, 557,000 miles. Timing belt done approx. 5K ago by a trusted shop.

Yes. Treat the fuel... regularly.
Better to pull the tank and take it to a steam clean.
Starving fuel pressure causes pump wear.
Always keep spare filters, and don't use diesel 911.
That's pure ethanol and will dissolve water enough to run thru your pump. As a trucker on older nozzle type injectors like the ALH or 2003 or earlier Cummins, or electric/mechanical fuel injection on bigger engines I always use Howes, naptha based injection cleaners, and in a pinch, 2cycle engine oil blended to the diesel, or ATF.
ATF is mostly oil based detergent, 2 cycle is mostly another solvent.

It's important to remember that once you have run any flavor of water or run dry any high pressure fuel pump , they will go bad quick
 

tripLr

Member
Joined
May 9, 2021
Location
Wa. State, USA
TDI
2002 Golf
Yes. Treat the fuel... regularly.
Better to pull the tank and take it to a steam clean.
Starving fuel pressure causes pump wear.
Always keep spare filters, and don't use diesel 911.
That's pure ethanol and will dissolve water enough to run thru your pump. As a trucker on older nozzle type injectors like the ALH or 2003 or earlier Cummins, or electric/mechanical fuel injection on bigger engines I always use Howes, naptha based injection cleaners, and in a pinch, 2cycle engine oil blended to the diesel, or ATF.
ATF is mostly oil based detergent, 2 cycle is mostly another solvent.

It's important to remember that once you have run any flavor of water or run dry any high pressure fuel pump , they will go bad quick

I mean methanol for the 911
 
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