Fuel draining back to tank?

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shezads
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Fuel draining back to tank?

Post by shezads »

I have a problem with my 94 zx td when starting from cold.
The engine cranks for about 10-15 seconds before catching. After this it starts fine all day.
This problem has started to occurr after I had the head rebuilt and replaced after a cambelt snap. The mechanic did take the engine out to do the job - due to restricted access in the bay.
The car was a first time starter before this.
Apart from this the car drives fine. The glow plugs are new - original Beru ones- so it is not that. Whilst the head was off the mechanic checked the injecters - they were fine also.
If I bleed the fuel system by pumping the bulb about 10-12 times then the car starts fine - straight away.
I think that the fuel is in the line is draining back into the tank. How can I rectify this?
What else could be causing this?
Stuart McB
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Post by Stuart McB »

The hand primer dosen't bleed the fuel system it only primes the fuel pump. To bleed the system first turn on ignition so that the stop solenoid is energised pump the primer bulb untill resistance is felt, that's the low pressure fuel side done now bleed the high pressure side by undoing the pipe work / nut at the injectors preferably one at a time then crank over on the starter motor, stop and tighten up the pipe work / nut. Do each one in turn. That should get rid of any remaining air in the fuel system if you don't have any air leaks. You may have the hand primer beiging to fail and so allowing fuel to pass back to the tank but do a search on this site under 'hand primer' or 'bulb' hope this helps.
monkeyman
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Post by monkeyman »

1). The first thing that comes to my mind is the thickness of the relaced head gasket, and was the head skimmed? If the head gasket is incorrect and is too thick this can lessen the compression and make starting more difficult from cold.
2). From memory there are 2 types of glow plugs, one type for turbo, one type without. Incorrect type of glow plugs can cause poor starting.
Hope that helps.
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AndersDK
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Post by AndersDK »

Since your starting problems disappears when priming the fuel bulb - there is clearly one distinct diagnose :
you have a (smallish) leak in the feed fuel line from pump and rearwards to tank.
Rubbish talking wrong HG, wrong glows and lo compression here, as then it would NEVER help to prime the bulb, and the engine would NEVER run good.
As the complete engine was removed for the repair job, it is in fact MORE than likely that one of the fuel lines has been disturbed.
rotodiesel
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Post by rotodiesel »

Your mechanic damaged the spill lines from the injectors, which had probably gone hard and brittle. A leak here can cause fuel drain back, which is undoubtedly your problem, without necessarily causing a visible fuel leak.
shezads
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Post by shezads »

Just to give feedback:
Finally got round to looking at the problem - would have gt garage to do it- but quicker to do it myself.
It was the return or spill lines on the injectors (as mentioned by Rotodiesel). - Had very minor splits - only one was leaking - the others were not but were split at the ends. Changed these - and result - started first time instantly, just like it used to.
Thanks for the help. Was getting tired of pumping that primer - had to pump it about twenty-five times just to get it started in the mornings!!
I ended changing all the spill lines - Citroen dealer wanted about £10 - for the pipe!! Got it from local GSF for £2.00 (1 metre)!
Stuart McB
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Post by Stuart McB »

Hey thats good and cheap news. At least we all going it the rite direction. [:D]
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