Author Topic: Air in fuel Lines (Read 3032 times)

angryjoe · « **on:** September 16, 2007, 10:48:52 am »

Hello, I'm new to VW and wondered why I keep getting airbubbles in my 97 Jetta TD GL? I think I've fried the starter trying to get it started.....any ideas?

Vincent Waldon · « **Reply #1 on:** September 16, 2007, 10:59:31 am »

Lots of possibilities and no easy answers other than to be a detective and work your way back from the pump to the tank.

Common sites for leaks are:

- at the pump itself... often the pump will leak fuel when it sits overnight if this is the case
- the clamps on the tubing between the pump and the fuel filter
- o-ring on the fuel filter
- the fuel filter itself, particularly the drain at the bottom.. although again this usually drips fuel overnight
- the clamps on the hose between the fuel filter and the metal line in the engine compartment
- the clamps on the hose between the metal line at the back of the car and the fuel tank

If your fuel filter is due (or nearly due) for replacement perhaps start there... lots of reports of this being the culprit... although it's never happened to me.

Vince

burn_your_money · « **Reply #2 on:** September 16, 2007, 11:01:06 am »

It could be a few things. The easiest way to figure it out is to take the feed line between the pump and filter and stick it in a CLEAN jar of diesel or ATF. Run the car off of that and look for bubbles. Then turn the car off and see if you are getting bubbles. If no bubbles then your problem might be the fuel filter or further towards the tank.
If you do get bubbles you may have a bad seal in the pump or possibly a problem on the return path but I don't think that would effect you.

angryjoe · « **Reply #3 on:** September 16, 2007, 11:05:29 am »

Hey Thanks. It does seem to only happen after it sits overnight. I'll try the jar trick after I change the starter.....is it hard to change the starter on this car, again I'm new to diesle and VW......

burn_your_money · « **Reply #4 on:** September 16, 2007, 11:08:08 am »

You need to jack the car up from the oil pan (use a block of wood between the pan and jack) because the 3 starter bolts also hold the front motor mount and the engine will drop about 2 inches when they are removed. The hardest part is getting the bolts back in since the engine needs to be lifted/lowered etc to get it lined up. It's not overly difficult, the last time I did it it took maybe 30 minutes but I've done it countless times.

angryjoe · « **Reply #5 on:** September 16, 2007, 11:15:20 am »

Thanks again, is it worth getting a used one, or is new the way to go?

burn_your_money · « **Reply #6 on:** September 16, 2007, 12:59:24 pm »

Depends on the price I guess. I would either get mine rebuilt or get a used one.

sprstu · « **Reply #7 on:** October 07, 2007, 11:13:14 pm »

dont know if youve fixed it or not, but check the inside diameter of the lines you are using. if your lines are too big you could end up with an air gap at the connection points where the rubber meets metal. what happens is instead of their being a good seal between the hose and where its clamped, you get a teardrop shape because you are starting to fold the hose in half when you crank it down with the worm drive, thus causing a small gap for air to get sucked in.
Also, when you take anything in the fuel system apart it a really good idea to replace the crush washers when you put it back together. that can become warped or "crushed" into a specific shape and when you go to put them back on if they're not in the same exact place that could cause an air gap.

angryjoe · « **Reply #8 on:** October 10, 2007, 06:24:48 pm »

So I got the air out, changed the starter, put in a new fuel filter.... but now it won't start at all. It just keeps cranking. Before, it would crank but smoke like a tire fire. Now, cranks but no smoke almost like there's no combustion. I know it's sucking fuel into the injector pump, but won't catch and run?

Author Topic: Air in fuel Lines (Read 3032 times)

angryjoe

angryjoe

angryjoe

angryjoe