Author Topic: 98 Jetta TDI (Read 7454 times)

coke · « **on:** September 14, 2006, 05:55:24 pm »

Persistent problem with my 98 Jetta TDI. It has 112k miles on the clock. I just replaced the fuel filter again, due to the massive amount of air traveling through the clear line. However, the only way I can get it started is if I fill the fuel filter first. It'll then start, but hauls still massive amounts of air after 30 seconds or so and after 60 seconds it dies and the filter is empty. Its as if the vane pump is not pulling fuel to the filter. Any ideas?

Slave2School · « **Reply #1 on:** September 14, 2006, 06:19:32 pm »

Does your filter have the thermostatic plstic "T" in it? I know the ones on the MK IV's will often leak air in there. Check to see if the O-ring is still fresh maybe? That's all I can think of.

SMOKEYDUB · « **Reply #2 on:** September 14, 2006, 07:36:12 pm »

i think there is check valves along the lines somewere. maybe there stuck? how much fuel is in the tank?broken line in the tank?when you get it running hold it at a steady fast rpm like 3000 or 3200

Slave2School · « **Reply #3 on:** September 14, 2006, 07:43:36 pm »

In my car the check valve was in the fuel sender, and I drilled that out (it restricted fuel flow when it got cold and I got got crap fuel in the winter)

coke · « **Reply #4 on:** September 14, 2006, 07:47:21 pm »

Im not entirely sure. I've blown air through both lines, feed and return. They aren't clogged up. The filter is new, so that rules that out. It could be the sender, im not sure. Where is the restrictor or check valve or whatever that you referred to Slave2School?

i've narrowed it down to two things. Internals in the pump (mainly the vein pump) or the lines to the tank. Or the sender, actually, thats 3.

QuickTD · « **Reply #5 on:** September 14, 2006, 09:16:28 pm »

Connect a hose to the filter inlet and stick it in a can of diesel, if it runs properly then you can look upstream, if it still acts up and draws air, then look downstream of the filter for the leak. The fuel pickup in the tank is craptastic, the little bellows on the pickup can come loose and cause air leak below 1/2 tank. Its not difficult to get to, so worth a look. The check valves, as mentioned, are of similar quality. They are located inline at the top of the tank and can be accessed through the removable fuel pickup/guage sender access panel in the trunk.

coke · « **Reply #6 on:** September 14, 2006, 09:19:38 pm »

I assume the check valves are the devices attached to the lines directly after the sending unit? I did notice these. I've had the sending unit out of the car. Its fairly accessible. Is there anything I should check on the sending unit itself to ensure proper function?

I just can't imagine the pump has 112k miles on it and the vane pump is already gone. My 90 Jetta has the original engine and pump with well over 263k miles and still draws fuel from the tank just like the day it rolled off the showroom floor. However, I do have a seperate issue with that.

QuickTD · « **Reply #7 on:** September 14, 2006, 09:26:26 pm »

The vane pump isn't gone, I can pretty much guarantee you that. Run the thing on a can of fuel to isolate the problem. It could be as simple as a bad crimp on the new filter, just because it's new doesn't mean that its good...

coke · « **Reply #8 on:** September 14, 2006, 09:42:21 pm »

Can't be that, tried it with the old filter too. No go. I too, thought of this. I will try it from a can of fuel, and let you know. Anyone else care to chime in?

Slave2School · « **Reply #9 on:** September 15, 2006, 04:17:07 am »

The check valve (in my car) is intergral to the sending unit, you have to take the sender out to see it.

coke · « **Reply #10 on:** September 15, 2006, 04:06:14 pm »

I've removed the sender, but I dont know what to look for. Any hints as to where it is and what I need to do to fix it?

Slave2School · « **Reply #11 on:** September 15, 2006, 04:15:23 pm »

Take the plastic basket off the bottom if it has it on there, I'm not sure if your style has that same setup. It was a pita to get out you have to drill the check valve out and pick the chunks out :|

Slave2School · « **Reply #12 on:** September 15, 2006, 04:22:39 pm »

ah here it is http://forums.tdiclub.com/showthread.php?p=647602

coke · « **Reply #13 on:** September 15, 2006, 04:43:35 pm »

My sender doesn't look like the one pictured there in that thread. Its very skinny on the underneath of the round portion, and it moves up and down on a spring. Im not having cold weather problems, i having all around problems. Temporarily I've installed a 2-5 psi fuel pump to keep the filter full of fuel, but without it, the fuel filter bails dry adn the pump wont haul any fuel. Even with the electric fuel pump, there is still an immense amount of air in the lines.

burn_your_money · « **Reply #14 on:** September 15, 2006, 04:54:03 pm »

Are there any fuel leaks? Perhaps try running the temp pump with the car off and see if you spot any leaks