AAZ Diesel Return Feed

[Wilma]

Hi there,
I wonder if anyone else suffers from this problem - in any case it may be useful information to some. About once a year mine won't start from cold in morning. Heater plugs OK and it was running perfectly the night before. Engine turns over fine, plenty of battery life. Removing the diesel feed to the pump shows the pipe is dry - its all gone back to the tank! Problem originally solved by friendly AA man. The little tiny rubber pipes which link up the excess fuel nipples on the injectors crack at the ends. This lets air into the system very slowly, so left overnight the air leak allows the fuel in the supply pipe to go back to the tank - or at least to the filter. Remedy is to replace the cracked rubber pipe (s), then bleed the system. For that I use one of those little bulb pumps you get for outboard engines, copper pipe in one end and rubber in tother, then disconnect main feed at pump end and put your bulb pump in line. (make sure its the correct way round - they carry an arrow to show direction of flow.) Pump away merrily , usually about eight to ten pumps, but in my case I start to feel some resistence. Start the engine, perhaps three or four goes and away it runs. Let it run for some time to clear the air in the pipework. Mine has a clear plastic section of return pipe and I can see the bubbles passing. The bulb you have put in the system can stay in place while it runs as it is designed to pass fuel in one direction only. Stop the engine after a bit and quickly disconnect the bulb and replace the feed on to the injector pump. There will be enough diesel in the system to allow you to start again, so do so and let it run once more to clear the air you have just allowed in.

If you have a problem finding the culprit in the first place, as I did today, go through the business with the bulb connection and start the engine. Let it run with the bulb in place. After three or four minutes I could see a tiny diesel leak at the end of the beastie.

Does anyone else have this problem? Its now happened to me three times, about twelve months intervals, and I carry a spare length of tube so I can cut it to size if needed. I now use unbraided tube as it's easier to examine. Each piece is only about 4 - 5 inches long. Any one know how to stop it happening? It catches you out when you least expect it but will not stop you once on the move as the injector pump capacity is greater than the air leak.

Incidentally these tank pumps are invaluable. Cost about £5 - £6 from a chandler. I carry one ready made up and use it any time I need to bleed the system. Saves that nasty tasting diesel.

Malcolm

[famous phil]

Hi, if your having problems with the fuel spill pipes I'd check for restrictions in the main return from the pump , there's a large volume of fuel that heads back to the tank , the reason is to help keep the pump/injectors cool .
the return pipe needs to be at least 5mm ID , if not you'll end up with pressure build up at the injector spill pipes+pump - also meaning that the timing advance curve of the pump will be affected , The palm (bulb) primers can also be found on PSA group vehicles , when priming up- the ignition should be on - to open the pumps shut off valve , I've seen a couple of pumps with blown seals where people have used the palm primer too forcefully