Air Leak again

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Vanny
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Air Leak again

Post by Vanny » Wed Mar 22, 2006 10:51 am

Again with the air leaks! Had it since i go thte engine back in though its now quite a bit worse! It takes around a minute with the engine off for sufficient air to get into the fuel lines that the car wont start without priming!

I've sat for some ten minutes today priming the bulb and while it goes tight after about 10 presses there is no fuel coming out of anywhere! I can here the air being forced out/getting in somewhere around the rear of the fuel pump, but i really cant figure out where its coming from.

I have already changed the leakoff pipes (twice) in vain hope of stopping the leak with no success. Something else thats a little strange, the car WILL NOT start without the glow plugs being connected for at least 3(ish) seconds where there engine is blistering hot, freezing cold or if i sit on the button for an hour!


My thoughts are is it possible that one of the brand new glow plugs isnt seated properly and the air is getting in through the thread of the plug?? There not obviously loose.

Other options, leak of pipes AGAIN, one of the fuel send or return pipes, the priming bulb its self letting air in, the fuel filter not sealing or something totally different?

Aim is to do it a service ASAP to include the oil and the fuel filters and see what happens, but does anyone else have any ideas? Generally she's running fine once started, and pulls like a train (ragged the canoe trailer upto 70 up a big hill the other week, was only tring to make it to the top, got scared when i realised how bleedin fast she was pullin!

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cavmad
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Post by cavmad » Wed Mar 22, 2006 11:34 am

Vanny, whilst not wishing to teach my grandmother to suck eggs it won`t be the same problem as I had with the TGD (now owned by Matt) will it? I recall my desperate bodge to replace the fuel filter resulted in me accidentally making a pin hole in the housing and it wouldn`t run properly until it was pointed out (by you, as I recall!) and the filter housing replaced.
Just a thought so don`t shoot the messenger please!
Vauxhall apologist.

jeremy
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Post by jeremy » Wed Mar 22, 2006 12:19 pm

Vanny - These sort of things are complete pigs - and sadly after all your investigation your original problem is still there.

I'm sure you know most of what I'm going to write but its not easy for me to work out what's been done or what is relevant so please bear with me.

You have a 1.9TD - probably with a Bosch pump. If it a Roto-Diesel - you can forget the leakoff pipes as they will make no difference.

You probably have the later plastic fuel filter housing sitting on the clutch end of the engine high up. These have a heater in the bottom controlled by a thermostat and this can leak round its fitting and admit air. I think the thermostat is accessible from the outside and can be removed and its seal replaced. there were some postings and photographs somewhere - either here or probably the Frenchcar forum or even the Citroen Z formula but I can't find them at the moment.

If your glowplug is leaking I'd have thought that fumes and unburnt fuel would be blown out when the engine was running. There is minimal suction on a diesel engine as it has no throttle and so not only would any air leakage be minimal but as its just more air it wouldn't make any difference at all. It would reduce compression which would mean a weak cylinder which I think you would notice. You could test for leakage with soapy water and a brush - just like a tyre - but if it was significant you wouldn't be able to get anywhere near it.

Good hunting

jeremy

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Vanny
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Post by Vanny » Wed Mar 22, 2006 8:21 pm

cavmad wrote: I recall my desperate bodge to replace the fuel filter resulted in me accidentally making a pin hole in the housing
Pinhole? I had to chew up two packs of gum to stop that hole :D


Yes it is a later arrangement, bosch pump (originally with that stupid damper), plastic filter housing, priming bulb etc. Will investigate the thermo housing, but the soapy water and a brush sounds like a bloody brilliant plan!