Can you help me diagnose a fuel issue?

Jeepaholic

Well-known member
Joined
Feb 1, 2013
Location
Fenton, MI
TDI
1999 Golf, two door. Manual trans, manual everything else.
I did a lot of searching, and that was my downfall. There's so much information out there, and lots of it was conflicting. So, I'm just going to type my specifics here in the hopes that someone can help me out.
99 Golf, TDI, 250K miles
Friday I'm driving to work and after about 11 miles it starts to stumble. This happened on the highway, after about 9 miles of country road driving and 2 miles of highway driving. I pulled onto the shoulder and it seemed to idle fine. So, I puttered on the shoulder for maybe another 100 yards before it just died. Here's some info that might come in handy.
I've only owned this car since the spring and this is my first winter with it.
I don't use any fuel additives (like diesel 911 or other anti-gell additives)
Never had bio diesel in it.
The temp was 12 below zero at the time.
I had about 1/4 tank of diesel.
It has a long crank issue, has since I've owned it.

I had it towed home and later that afternoon, when the temps warmed to a balmy 8 degrees it started. I then drove it to the gas station 2 miles away, added some anti-gell, filled the tank, and drove back home. Today, temp was about 25 degrees and I took it for a longer drive. I only made it 1 mile to the highway, then 3 or 4 miles on the highway before it started to buck and stumble again. I pulled off and drove surface streets home and all was well. I decided to replace the fuel filter since I have no idea how old it is. I replaced it and primed it and it did start after lots of cranking, but wouldn't restart a short time later.

Fast forward to today. So I went out to the garage and primed the filter again. It only took a few ounces. It started up after a LOT of cranking and ran fine. I let it idle for an hour while I dug out from snowmageddon. It idled and revved fine. I shut it down and restarted immediately. It took maybe 5 seconds of cranking to start. I shut it down and restarted again, it took a bit longer to start this time. I'm suspecting the tandem pump but don't have a way of checking pressures.
I'll add this. After the initial failure, when I got it started the next day and pulled it out of the garage there was about an 8" puddle of oil on the floor. this car does seep oil, but does not spot on the driveway. I suspect the tandem pump leaked fuel down the engine, washing oil from the engine and skid plate? I cleaned the area under the pump and it looked dry after the hour of idling.
Any input before I drop a few hundred on the pump?

Sorry it was so long and blathering, but any help would be greatly appreciated.
 

CopaMundial

Veteran Member
Joined
Jan 30, 2011
Location
Southeastern PA
TDI
03 Jetta Wagon 5sp (New to me Oct 2014) 03 Jetta 5sp (RIP Aug 2014)
First things first, your car should have an ALH engine code. That engine does not have a tandem pump.

When you replaced the fuel filter, did you also replace the small O-rings on the tee fitting on top of the filter?

Check to see which version of the in-tank fuel sender you have. Here is how to check.
http://forums.tdiclub.com/showthread.php?t=98600


Can you describe on this diagram where the fuel and oil seemed to be coming from?

 

Lensdude_com

Veteran Member
Joined
Oct 31, 2004
Location
Edmonton, AB
TDI
99.5 MK4 Jetta (ALH) "Betty" (sold), 2005 MK4 Jetta (BEW) "Stinky-Pete"
Your '99 Golf has the ALH engine that uses a big belt driven injection pump with a separate cam-driven vacuum pump...
The BEW engine has a cam-driven injection pump with a vacuum pump in the same unit so that's why it's referred to as the tandem pump...
Get some rags/shop towels and wipe away the accumulated oil/fuel from the engine where you suspect it's leaking from.
 

Jeepaholic

Well-known member
Joined
Feb 1, 2013
Location
Fenton, MI
TDI
1999 Golf, two door. Manual trans, manual everything else.
Thanks for the replies. The rear of the head under what I understand is the vacuum pump. I sprayed that area off under that pump and it's staying dry.
I just started it and drove it about 20 miles and all seems to be ok, but tomorrow morning will be telling.
Thanks a lot folks, I appreciate your help.
 

Lensdude_com

Veteran Member
Joined
Oct 31, 2004
Location
Edmonton, AB
TDI
99.5 MK4 Jetta (ALH) "Betty" (sold), 2005 MK4 Jetta (BEW) "Stinky-Pete"
Thanks for the replies. The rear of the head under what I understand is the vacuum pump. I sprayed that area off under that pump and it's staying dry.
I just started it and drove it about 20 miles and all seems to be ok, but tomorrow morning will be telling.
Thanks a lot folks, I appreciate your help.
...actually, the side of the cylinder head closest to the air filter box is the location of the vacuum pump...
it will not have any liquid leaking from the pump but could have a leak from the valve cover seal where it goes over the camshaft bearing.
 

CopaMundial

Veteran Member
Joined
Jan 30, 2011
Location
Southeastern PA
TDI
03 Jetta Wagon 5sp (New to me Oct 2014) 03 Jetta 5sp (RIP Aug 2014)
The rear of the head under what I understand is the vacuum pump. I sprayed that area off under that pump and it's staying dry.
Ok, so I understand the confusion a bit.
On later cars that similar location is the tandem pump. But on your ALH that's just the vacuum pump. There is no fuel in that location to leak. The more common issue with a leak in that area on an ALH car would be either oil (in small amounts) getting past the cam shaft bearing or coolant. The coolant there could be leaking either from the the flange where it meets the head or (more often) from the coolant temp sensor which is right there on the back side.

Here's a photo to help visualize the spot I'm describing.




So I'm suggesting that may be the source of leaking, if it was coolant.
It's possible, but not all that likely, for the Coolant Temp sensor to give you hard start symptoms. It's more likely that it's fuel starvation as you initially suspected.

Do you have air in the clear fuel line going from filter to injection pump, if so, how much air is in there and does it move when the engine is running?
When you replaced the fuel filter did you replace the O-rings on the tee fitting?

Also, since this is your first winter with the car, and you're in a cold climate you should double check which version of the fuel sender you have. There are multiple versions of this part, some versions have proven to be problematic in cold climates while others do much better.

How to see which version of the part you have:
http://forums.tdiclub.com/showthread.php?t=98600

When you're having this difficulty starting, how fast is it cranking? Often the initial source of difficult starts is obscured by the fact that the battery gets overtaxed, especially in winter. So while fuel may be the root issue, the symptoms may be complicated by a weak battery now.

(*edit* Since you mentioned that you had the car since spring and didn't know how long the fuel filter was on there, you may also want to check your air filter, snowscreen, and EGR valve to ensure that you don't have blockages limiting air flow to the engine as well)
 
Last edited:

Jeepaholic

Well-known member
Joined
Feb 1, 2013
Location
Fenton, MI
TDI
1999 Golf, two door. Manual trans, manual everything else.
Ok, so I understand the confusion a bit.
On later cars that similar location is the tandem pump. But on your ALH that's just the vacuum pump. There is no fuel in that location to leak. The more common issue with a leak in that area on an ALH car would be either oil (in small amounts) getting past the cam shaft bearing or coolant. The coolant there could be leaking either from the the flange where it meets the head or (more often) from the coolant temp sensor which is right there on the back side.
Thanks very much for the clarification.

Do you have air in the clear fuel line going from filter to injection pump, if so, how much air is in there and does it move when the engine is running?
When you replaced the fuel filter did you replace the O-rings on the tee fitting?
I had a ton of air this morning, I didn't look at that this afternoon because, quite frankly, I was surprised it started and wanted to drive it. I'll check later tonight when I go to shovel snow for the 5th time today. I did replace the two o-rings on the tee fitting.

Also, since this is your first winter with the car, and you're in a cold climate you should double check which version of the fuel sender you have. There are multiple versions of this part, some versions have proven to be problematic in cold climates while others do much better.
Again, thanks! I'll check that tomorrow. If I don't have the H version, should I go buy that version or is this something that can be modded?

When you're having this difficulty starting, how fast is it cranking? Often the initial source of difficult starts is obscured by the fact that the battery gets overtaxed, especially in winter. So while fuel may be the root issue, the symptoms may be complicated by a weak battery now.
Hmm, that's tough to answer. I don't know how fast it's cranking, but I did notice, when it wasn't starting (I'm assuming lots of air in the lines) it was cranking over much faster. The battery is new, and is a proper battery for a diesel, can't remember the CCA rating, but it was $160 at Nappa and is specific for the TDI. After a few tries, I put a small battery charger on Boost to help it out.

(*edit* Since you mentioned that you had the car since spring and didn't know how long the fuel filter was on there, you may also want to check your air filter, snowscreen, and EGR valve to ensure that you don't have blockages limiting air flow to the engine as well)
The air filter was replaced a few thousand miles ago when the oil was changed, but I'll check the snow screen and EGR tomorrow as well.
Thank you all very much for your help. I'm not a VW enthusiast like the rest of you here, but I appreciate the willingness to help me keep it on the road. Even though I'm not an enthusiast per se, I'm a TDI fan for sure. I get 50+ MPG (not in the winter haha) consistently, and the car is comfortable and much peppier to drive than my other diesels were. And at 250K, I expect things to crop up; another reason I appreciate the help.
 

CopaMundial

Veteran Member
Joined
Jan 30, 2011
Location
Southeastern PA
TDI
03 Jetta Wagon 5sp (New to me Oct 2014) 03 Jetta 5sp (RIP Aug 2014)
Again, thanks! I'll check that tomorrow. If I don't have the H version, should I go buy that version or is this something that can be modded?
If you have the older (non arctic approved) version, then some people have reported success from drilling out the check valve in the fuel sender. There are some details in this thread below.
One item to note, if you're pulling that fuel sender out for whatever reason then take care to avoid spilling diesel fuel all over the carpet. The lower the fuel level in the tank when you open that up the better. You probably shouldn't remove it with the tank full beyond say 3/4.

http://forums.tdiclub.com/showthread.php?t=68872
 
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