306td Bleeding Fuel System

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Tue 3 Oct 2006 17:47
306td Bleeding Fuel System - thomp1983
hi, '94 306td just had head rebuilt and replaced after seized tensioner.

could anyone tell me if there is a bleed nipple on the bosch fuel pump for removing air from the system? i know there is on a lucas pump, but not sure with the bosch.

basically it is taking a long time to turn over and fire which i know is air in the system as you can see it in the clear pipes. i have cracked off the injectors and turned it over for awhile which has helped improve things but thee's still air there

chris.
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Tue 3 Oct 2006 17:52
306td Bleeding Fuel System - 659FBE
No there isn't. You could release the pump return union whilst you prime the system but there's not a lot of point. Remember there is a pressure release valve in the low pressure side of these pumps, so a significant bleeding pressure is needed to prime the pump. This is usually achievable with hand pressure on the primer, and will often cause the valve to buzz - this is normal.

When you get the engine running, operate the primer whilst the engine is at fast idle - this shifts the air trapped in the filter head, but otherwise, these pumps vent themselves.

659.
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Tue 3 Oct 2006 18:03
306td Bleeding Fuel System - thomp1983
ok thanks, may have to investigate the system some more then as the air is there consistently so may be a pipe join ive overloked and not tightened properly

chris
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Tue 3 Oct 2006 19:37
306td Bleeding Fuel System - 659FBE
If you have recently disturbed an old XUD engine, check the injector leakoff rubber pipes - they go hard, crack and leak. This problem would give the continuous air ingress you describe. New pipe from GSF.

659.

Change the blanking cap on No 4 injector leakoff also.
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