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61K views 33 replies 9 participants last post by  rtroy 
#1 ·
Hey everyone, I'm new here.
Background: I recently acquired a 1981 diesel Rabbit as my first big "project car." The car was full of mice and had been sitting vacant for ~8 years. Paid $400 for it, as it was complete and body-wise good shape for Michigan (where I live.) The rig didn't run, but would crank. I stripped all interior once I got home, and focused on getting the engine running. I drained the tank, replaced fuel filter, all new clear fuel lines to the injector pump and between the injectors. Cranked it and she fired up, good. I had done my best to prim the system, had the fuel filter full of diesel, and the injector pump was primed via vacuuming the return line.
Now the problem: The "Pesky Wittle Wabbit" won't draw fuel. I'm sure there is no air in the injector, it's been primed and primed. (I hook my brake bleeder up to the return line and suck fuel from there.) When the brake bleeder is hooked up, and I start it, it will run beautiful, as long as the return line has some vacuum on it. But once the bleeder is removed and the return line is placed back on, the engine will slowly rev down, lope and finally quit. The whole time it's dieing, no fuel is being pulled from the filter to the injector. The engine will run fine if a jar of fuel is hung and connected directly to the injector pump. :confused:

Does anyone know why my injector pump wont draw fuel? Tank is clean, both incoming and return lines clear, no air leaks, new fuel filter.
ANY help would be appreciated. Thanks in advance :)
 
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#2 ·
Sounds like you either have a timing issue with the pump, or a air bubble in the manifold.

Crack each injector port at that manifold one a a time while the engine is cranking. Then tighten. If that
don't work then you are looking at a possible rebuild of the injection pump.
 
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#3 ·
Cracked the injectors as you said, and problem still resides. The only way I have found to get the engine running smoothly, is to put the brake bleeder on the return line and draw fuel manually into the injector pump. Could it be the fuel shutoff? I hear it pop when the key is on, but maybe it's gummed up and sticking? Thanks for the help, and the quick response!
 
#4 ·
If it will only work when you are pulling fuel through it, then you have a pump that isn't pumping as it can't draw. To see if it is external or internal If you take a bucket and fill it with fuel, can the pump pull it out of the bucket with no filter? As it could be just a bad pump.
 
#5 ·
Charlevoixboy, use a high pressure air hose and blow back through the pick up line there may lie 8 years of wee bits and pieces. if that don't work then do what brian said. If you need a pump I got one from Emiata.com 250.00 after i sent the core back, worked like a charm, you need the timing "tool set" too it's like 70 bucks i think, or borrow one from your local VW mechanic. Heres the other issue it may seem impossible but I bought my neighbor Diesel Dan a couple fuel filters on line and one was bad, his 1.6 loaped sputtered and stalled, he then put the other one on and worked like a charm. hope this helps..MM
 
#6 ·
Put fuel into a bottle and inserted the incoming fuel line (after the filter) as Brian said. It looks like it tries to pull fuel, but not very well at all. Still runs like crap. Guess I will look into a new pump. :/ Hey, at least I know the engine is good (no burning oil, leaks, good compression.) Is there a rebuild kit I could buy to rebuild the pump myself?
 
#7 ·
Hate to bump and old thread, but does anyone know what part of my pump is not functioning correctly? Personally, I'd like to try the rebuild myself. Symptoms are (and described as best I can) :
When a funnel attached to the incoming fuel line, is filled with diesel and attached to the hood (above the injector pump) the car will run just fine. When the incoming fuel line is placed in a jar filled with diesel (below the injector pump), it will not draw fuel into the pump and runs rough, misses and sputters to a halt. So as long as the incoming fuel is being forced into the pump, either by gravity of pressure, the engine runs smooth. But the injector pump wont draw fuel on its own power. There aren't any air bubbles in the system either. Any insight is appreciated!
 
#8 ·
You either have a air leak on one of the seals, or a problem internally.

The ip pump when you take it apart is a very simple thing you have a cylinder with 3 or 4 wiper blades that spin around in the chamber and create not only suction to pull the fuel out of the tank, but also pass it through a diaphragm to create pressure.

There are places where you can buy a new one that is tuned for a few hundred plus core. Mushroom Man can steer you there.
But I would verify that you don't have a leaky fuel line from the hard steel line to the ip. I had to replace that clear hose as I kept seeing bubbles in it, and finally fingered out that it was leaking at the filter banjo bolt.

Don't remember much more as it was 95 when I had to repair mine after 15 years of spinning.
and I had to repair it after having thrown away my spare about 6 months earlier....damnit.
 
#9 · (Edited)
#10 ·
Just to update the thread, I tore the IP down and sure enough, the vanes were varnished in place. I put a good polish on the vanes, and reassembled the pump. The Rabbit runs beautifully now. Made the 3 sided bolt removal tool by cutting out an old 1/2 socket. The whole rebuild cost was $0. It's nice to hear the engine purr on its own. Thanks for all the help!
 
#12 ·
Good to hear that shes on the road again. MM
 
#13 ·
Instead of making a new thread, I'll use this one. So I've been driving the VW for a while now and have been having this reoccurring problem. The car looked at though it was pulling air somewhere from the fuel tank to the IP. After some digging I found that the screen in the tank was plugged and causing the tiny air particles in the fuel to expand as the pump drew a vacuum on the line. After cleaning the tank screen and blowing the lines out, I have clean lines and filter. The bubbles have disappeared and the car runs with much more power. Now the kicker- the car will start and run fine, but after cruising at road speeds and coming to a stop, the engine will shudder to a halt (stall.) After waiting a couple of seconds, the engine will restart and go on it's way as if nothing happened, until the next stop. I'm stumped, fuel filter new, clamps on all the lines, tank appears clean from sending unit hole, supply and return line blow air freely. Problem still occurs without tank cap. I've read that there is a rubber piece in the bottom of the tank that will deteriorate and get sucked into the path of the pick-up line, and cause the stall and quick re-start. Anyone heard this?
 
#14 ·
I have heard of the pick up line in the tank rotting out and internally collapsing. I personally never have seen it.
 
#17 ·
No it is like sucking on a straw that you put your finger over the other end...

Since the tank is a bottom feeder, the fuel and air usually don't mix in the tank.
 
#19 ·
OK, I pulled off the fuel line to the IP and ran a piece of hose into a gallon of fuel. Started her up and it pulled fuel JUST FINE. After getting up to running temps, the throttle response started to get lazy and not as responsive. Then it wouldn't idle. I could turn the idle up but after revving the engine, the idle will hang (because of the screw being adjusted in.) I'm unsure if there should be a one-way in the incoming fuel line (I don't have one), but after shutting the engine down the line gravity feeds back and pulls a largish column of tiny air bubbles out of the pump. The problems only occur when the engine is at operating temps, so I have to ask the question: could my IP be timed off (too advanced) by a degree or 2? I've timed it the hill-billy method per instructions off another VW forum. Would this explain why it wont run right at warmer temps? Or could the IP be full of air? It runs fine cold. Thanks in advance
 
#20 ·
Yes that could be a very good reason.
2 get rid of that air. The air bubbles can eventually stop the ip from pushing fuel out to the injectors.
Air bubbles isn't a good thing.
 
#23 ·
After installing an inline fuel pump, the problem is still there. Then after peering over the hot engine and complaining about how the coolant system was pressurizing, one of my hoses blew (split right down the middle.) Replaced the hose and started her up with the coolant bottle cap off and had bubbles and lots of air in the system. Putting your hand over the hole would instantly build pressure. Will report back after head gasket replace. Does anyone know if you can see the number of notches in the head gasket before removing it? New bolts will also be purchased when doing the gasket.
 
#27 ·
First, check your glow plugs remove the number 4 and jumper it straight to the battery. Hold it with a pair of pliers as it will get hotter than a fire-cracker. If it don't then it is bad, weak glow plugs are the biggest cause for hard starts.

The other issue is if you have any air in the clear plastic tube going from the filter to the ip. If it is sucking air, then that is more the issue than an in-line fuel pump.

Usual places for it to suck air, are the banjo fittings on the ip, as well as the filter.
You can remove the bolt. The take the 2 copper washers and sand them smooth. Then holding them over a flame until they change from bright to dull.
This will re-condition them to make them seal better. Napa carries those as do some parts stores. (folks call them crush washers).

Verify the two things, and someone will be along to tell you where and which pump to buy and where to wire it in.
 
#34 ·
Usual places for it to suck air, are the banjo fittings on the ip, as well as the filter.
You can remove the bolt. The take the 2 copper washers and sand them smooth. Then holding them over a flame until they change from bright to dull.
This will re-condition them to make them seal better. Napa carries those as do some parts stores. (folks call them crush washers).

Verify the two things, and someone will be along to tell you where and which pump to buy and where to wire it in.
Please Note: Anyone who calls those "crush washers" are using the wrong term!

REAL crush washers are one-time washers that are typically metal on which one surface has some kind of sealing agent - cork, plastic, etc, depending on usage - that gets curled into the piece during manufacture. Once crushed, it cannot be uncrushed. Annealing gets you nothing. An example of these are on early, air-cooled Volkswagens like the Beetle and are famously used on the sump plate oil drain, and oil pressure control piston plugs.

THESE washers are properly called "sealing washers" and are typically available in three materials: copper, aluminum or a fibrous material usually just called "fiber." All three of these should work well with diesel, but copper is typically the choice for durability, cost, and availability. However, copper seals the worst of the three. I use aluminum for most applications - harder to find but seal MUCH more easily and are also reusable, typically without annealing, though they also can be annealed using a cigarette lighter...

Hope this helps you source parts more easily!

Richard
 
#28 ·
I just got my pump back on and getting air in clear line between filter and Injector pump. Bubbles are coming out of pump and fills up clear line. guessing from what I've read it could be from the copper washers atop the pump. But it was good to hear it come to life....finally....lol
 
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