DRT A3. Theories anyone ?

DRT= Dead Right There (FYI). A3 died while driving. Severe power loss, eventual stall - wouldn't restart. No fuel. Will run/sputter on ether. My assumption was a clogged check valve (top of fuel tank). I've had that happen in the past. Same exact symptoms. No dice. Check valve was clean and moving freely upon inspection. Next I changed the fuel filter. Didn't have the opportunity to cut open old filter to check it (got tossed) so I don't know how bad it was. Fuel looks good, truck has been run quite a lot lately. Probably 8 or 9 tankfuls in past 2 months or so (not old fuel). Also more than half tank of new fuel had been burned prior to shut down (not bad fuel. Well, could have been bad fuel, but not likely). Cranked her and cranked her, not pulling fuel. Next, I opened the drain valve on filter housing, pressurized tank w/ air to get fuel moving through new filter. Note: I was not able to get any fuel flow to/through the filter housing drain with air pressure. I was using a 20 gal air tank that initially had 125psi and an air gun/fuel soaked rags as seal. Didn't have an air supply where I was. Perhaps I ran out of air too soon, but perhaps there is a blockage between tank and filter. Sooo, I disconnected the supply line from the pump and ran a hose directly into a 5 gal fuel can sitting on the fender (higher than pump) and cranked some more. Still wouldn't pull fuel. Next, checked voltage to fuel shutoff solenoid - checked good at 24V. Solenoid switch tested good as well. Lastly, pulled solenoid and checked plunger - clean and freely moving. operates correctly with 24V applied. Guys, I'm out of ideas now. Anyone have any theories ? I hate the thought of towing the poor girl somewhere and paying somebody to figure out just what the @#$% is going on. Thanks in advance for any ideas.

Could be sucking air in the line between the tank and the injector pump.

rivercreek said:

I disconnected the supply line from the pump and ran a hose directly into a 5 gal fuel can sitting on the fender (higher than pump) and cranked some more. Still wouldn't pull fuel. Anyone have any theories?

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Try hooking a hose up to a gravity fed tank and see if it will run. Sounds like a problem with the injection pump.

Geat title that will really help future searches.

I thought A3s didnt have an injector pump??? Algae in lines? get some Biocide! was the oily water seperator peeing like a faucet before this happened? I might suggest the fuel pump taking a dump but, you said you couldnt pressurize with air... Please keep us posted!

wreckerman893 said:

Could be sucking air in the line between the tank and the injector pump.

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Go to part store get a small electric fuel pump and you can feed fuel through filter housing drain to purge system. You can even run it home this way. If it doesn't run you have other problems. There is an injection pump. Its low pressure. It feeds the back of the head. I can give you my number if needed if you need more help from there.

It's possible that the fuel line has deteriorated and is collapsing internally, sealing itself off. I've seen this happen and the exterior of the fuel line still looks perfect. I would try bypassing the flexible fuel line to see if this is the problem. Also, open the drain cock on the bottom of the fuel filter housing. Make sure the drain cock isn't plugged up. They often fill up with crud and need to be rodded out with the drain cock open. Crank the engine and see if fuel squirts out. When I first got my A3, the drain cock was plugged tight and took quite a bit of rodding out to get it cleared.

My a3 was acting up bad,It ended up being algae in the fuel..

There are check valves before and after the piston pump and a regulator after the head to maintain fuel pressure in the head. If either one of the check valves go bad or get crud in them, they won't seal. The fuel actually passes through the piston pump before the filter. That is why I installed an in-line water separator just after the tank on mine. You can force feed the fuel through the system but you have to disconnect the return line and build more pessure in the tank than the regulator restricts. And that may be too much pressure for the tank. Usually you can just add some pressure to the tank and crank the engine till it fires. We are in Marshall, so if you need help let us know.

Just get some one with an a2 to tow you home.

Monkeyboyarmy said:

There are check valves before and after the piston pump and a regulator after the head to maintain fuel pressure in the head. If either one of the check valves go bad or get crud in them, they won't seal. The fuel actually passes through the piston pump before the filter. That is why I installed an in-line water separator just after the tank on mine. You can force feed the fuel through the system but you have to disconnect the return line and build more pessure in the tank than the regulator restricts. And that may be too much pressure for the tank. Usually you can just add some pressure to the tank and crank the engine till it fires. We are in Marshall, so if you need help let us know.

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What you did is what the military should have done. It looks like a very good professional installation.