Air getting into fuel when parked uphill

Got an issue with air getting in the fuel system but only when the vehicles parked facing uphill. Will fire up straight away and will run on the fuel in the injector pipes for a few seconds and then will die.

However when jump leads are connected to another car and the engine turned over until air is expelled the engine will run fine, and will start up again about half hour later. But if its stood overnight it gets air in the system and wont run.

Ive checked all unions and jubilees fir tightness, where would the air most likely be getting in?

Its perfectly fine when facing downhill or on the flat.

Engine is 2.5na in an 88 s3

How much fuel is in it? The pick up pipe is closer to the front, so if it's uphill facing, that might be it, also I'd make sure you really know what's in there, Landrover fuel gauges have a habit of telling us lies now and then !

Got about a third of a tank

Well I guess the cheap way to find out is fill it up and see what happens!, I think the unions on the top of the tank are cast steel ( or similar) could have cracks ? Or even the pick up tube?

It's likely a pin hole in a feed pipe somewhere, also check all the priming points on the injector pump and the sediment bowl have gas tight seals - a set of copper washers for the priming points is worthwhile.

My bus had that problem and I had to prime by hand...a #### of a job with a 15' long fuel line...or risk a flat battery!

You need to fill to brim and try leaving on the hill again. If it still does it then as dom says a pinhole in a metal union or hose is likely. It will sometimes ****fuel if its big enough and in front of lift pump. Behind lift pump the fuel is sucked so a hole will suck air not puss fuel. So look in between lift pump and tank fittings.

Update, i swapped the washers on the leak off pipe just in case and i noticed the plastic drain key under the filter was wet.

Swapped the oring on that and fired up with the jump leads and let it run again.

Will try and start it again tomorrow to see if that was the culprit