Thread: Air leak, where?

Park it nose down - the leak should reveal itself overnight with the slight pressure of the fuel in the tank on the joints.

typically 1 of 3

1. check valve for the lift pump.
2. the lift pump is leaking
3. the injector pump is leaking ing down

you might also have a dodgy return line seal OR an injector thats putting bubbles into the return line and pressurising it from within the filter. While its running or starting it regulalry you wont notice it to check for this run the engine to temp then crack of the return line from the top of the filter if it comes out a creamy white thats the problem.

Same symptoms on mine a while ago. Turned out to be the crush washers on the inlet pipe into the lift pump.

Mine showed up with a decent puddle on the driveway after a few minutes of parking nose down with a full tank of fuel.

I'd also ordered one of the bosch priming pumps off ebay around that time as I though that maybe it was leaking back through somehow since it leaked out quite a bit while priming.
Now much easier to prime, and I reckon a good investment for around $25

Steve

Originally Posted by steveG

...

I'd also ordered one of the bosch priming pumps off ebay around that time as I though that maybe it was leaking back through somehow since it leaked out quite a bit while priming.
Now much easier to prime, and I reckon a good investment for around $25

Steve

Mine cost me more than that, as I needed one in a hurry, but I agree. So much easier to prime now...

Pressurise it from the tank supply end or just pressurise the whole tank slightly. You'll find the leak immediately.

A few summers ago I chased the perfect leak in a connector. It would suck air in, but absolutely nothing got out. I was able to liven up the 12v pump that was still in the system and found it in seconds (after two weeks of hunting).

I also had an intermittent cut out problem a few years back- where engine would start & travel anywhere from 200km to 2km before cutting out by the side of the road,in the dark, not always in the best spot & a long way from anywhere- -no rhyme or reason why it was 2 or 200km between stops (didn`t relate to fullnes of fuel tank!) - just cracked the bleed nut on the injector pump , hand primed & away again. Got a bit sick of this on a trip Syd- Melb-Syd!
I had recently replaced the hand primer - studied this very forum & came up with pressurising the fuel line from the tank end - then went along the fuel line with a torch looking for air bubles/fuel leaks - discovered small air bubling ( not present during normal "running" ) where hand primer screwed into lift pump. All it required was literally a tenth of a revolution with a spanner to tighten the hand primer & no more problems!
Also make sure that the copper washer is correct - a slightly smaller OD & ID washer may not sit properly in lift pump/hand primer "Seat" resulting in potential air/fuel leak problems.

Thanks for the replies. Full tank of fuel and parking nose down on a hill found it. Slight weep from the banjo bolt under the fuel pump (where the strainer is).

Tightened it up, so will see if that fixes it.