Car engine turns, but won't start sometimes

I've got a Passat B5.5, 1.9l AVB engine. Starting half a year ago, every couple weeks it refuses to start in the morning. Now this is happening more often and over the last few days it also happened in the afternoon after not using the car for about 5 hours. The problem is intermittent, but happens more often lately. Sometimes the engine won't start at all, other times it starts for a second, then dies and doesn't start again. In the latter case, holding the gas pedal down seems to help avoid the engine quickly dying on occasion.

The engine turns, battery is new, when turning the key lights show up and then go off as usual. When it won't start, the only way to start it is to manually close the EGR valve (I think that's how it's called) for about 10 seconds (so no air goes into the engine) while another person tries to start the car. After that, releasing the valve usually causes the engine to start.

The glow plugs have been replaced. A year ago an injector and the o-rings on all injectors have been replaced. A few days ago all filters have been replaced. Immediately after replacing the fuel filter, the car took very very long to start. I checked all the fuses. I have a VAG COM but apart from checking injector values I don't know what to check with it to figure out the problem; there are no errors showing up. It seems that air temperature and fuel level in the tank don't influence this behavior.

My mechanic thinks it might be the fuel pump in the fuel tank; he says that also caused the difficult start when fuel filter was replaced. Others think it might be the high pressure pump, or something about the injectors, but basically what I'm told is I have to keep replacing parts until the problem goes away. Unfortunately, some of these parts are not cheap and am hoping I won't have to replace expensive ones that are not broken.

I found a few threads on the forum loosely related to my problem, but now I'm stuck, so I am hoping you guys can guide me as to what else I should check or which parts are more likely to be causing this behavior.

Thanks a lot,
Mihai

If you have a pump in the tank, when you turn the key to ON, you should hear the pump. If you don't, then most likely the pump is dead, but even if you do, you may still have a dead pump.

Pull the hose coming out of the filter at the head and put the hose in a container and turn the key on. You should get a god supply of fuel there. There is a link in my signature about how to test this with pictures and numbers and other stuff.

Check your No 219 ECM relay. Maybe that is the issue.

Yes, check the relay for the power relay (219).

It could also be the "in tank" tandem fuel pump.

When you turn on the key (where the dash lights come on) NO Cranking-- have someone put their ear to the outside rear quarter panel of the car.
They should hear the pump coming on and pressurizing everything.

Your post states you are in Romania and that you have the 1.9 engine.
I am making the assumption the BHW engine is similar to your car.

Thanks

To check the fuses and relays (assuming no power, at the pump connector, when you turn the key to on:

1. Check fuse #28. If you don't get 12V at the fuse, and the fuse is good, replace the 219 relay in the ECM box.

2. if you get 12V here but not at the pump connector replace the 373 fuel pump relay. As a short term fix you can steal the one labelled cooling fan in the picture ( it is only used for an overheating condition IIRC).


My 373 relay failed a few months ago.

Anybody have a VW part # for 373 relay (fuel pump) ?

May not be a bad idea to have one on hand.

Anybody have the VW factory part number for the fuel pump relay (373) ??