STILL needing to Prime fuel in the morning

citroenxm · Post by **citroenxm** » 21 Apr 2011, 21:00

Right then heres a good one for you lot.

FIRSTLY. I dont need the obvious causes! Its NOT causing this problem, thats why im putting this now up here...

Car: 1994 TD Xantia. Bosch Fuel.

Problem: Morning starting.

Firstly the AA advised Heater Plugs... So I duely bought a set of new plugs, and fitted them one by one.. however, as I removed each old plug, everyone was working! If the owner primed the fuel up on the squeeze bulb the car would then start instantley! So that prooved that the heater plug cuircuit IS working. So thats part one ruled out.

I then replaced the Squeeze bulb - same result still needed a morning sqeeze prime.

Checked the return pipe on the back of the engine, that was all intacked with no leak..

So the next thing, ** NAUGHTY BUT NO CHOICE ** I have now removed the fuel filter temperary from cuircuit and put the fuel direct from the primer to the Pump.. surely that must cure it..??

NO!

They still need to prime the fuel in the morning.

Thankyou for reading this far if you have got this far.

My Q is.... What next????

Pump seal is fine, no leaking fuel, no fuel on the cam belt either.

Cheers
Paul

Chlorate · Post by **Chlorate** » 21 Apr 2011, 21:34

Not sure why the AA would advise glow plugs there, not being connected to the fuel plumbing and whatnot...

How are your injector leak-off pipes? They do tend to harden and split over time that could cause a slow air leak.

Although that didn't solve the air leak problem in my car, was something else fuel filter related.

-Alex

Xaccers · Post by **Xaccers** » 21 Apr 2011, 21:36

Crack in the fuel line between the tank and the primer, crack in the fuel line between primer and filter housing.
Leak off pipe's cracked and letting air in, pump seals perished and letting air in.

Have you replaced any of the fuel lines with clear piping yet?
Do that.
Rev the car hard once you've done it (from the lever on the pump) and look for bubbles.

vince · Post by **vince** » 21 Apr 2011, 22:09

Hi Paul,

I once had this on a VW TD. We solved it by starting athe pump and working backwards as follows. We disconnected the fuel lines to the pump and put the feed line into a jug of diesel. The car started and ran fine = no problem with the main pump. moving backwards along the line we hit the fuel filter housing. Re connected that back into the circuit and problem returned. Bypassed that connecting the tank to the pump lines and again it ran fine....Changed the complete fuel filter housing and it still had the problem.....turned out that the fuel hose clips were not completely round and so had the tiniest gap that was drawing in air and vacating the pump on start up. Once it was running it always ran fine with no problems whatsoever. The clips were ditched in favour of cable ties and the ends of the fuel filter housing pipes coated in a thin covering of vaseline before the pipes were reconnected. = 100% CURE

It seems you have done some of this already so if it isnt that im stumped

dave2011 · Post by **dave2011** » 22 Apr 2011, 06:29

seams like the theres air leak some where causeing the system to depressurise.got this problem on mine due to a leaking bosch pump.

AndersDK · Post by **AndersDK** » 22 Apr 2011, 09:00

Using weak air pressure (hand/bike pump) pressurise the feed line from filter back to to tank.
That will instantly show any pinholes in the fuel line.

spider · Post by **spider** » 22 Apr 2011, 09:23

Air ingress in the union on the pump inlet (the copper seals)

Less likely but not unknown, the high pressure pipes are not sealed properly. I've had this no leak but it misfired a bit from cold, took ages to work it out then I nipped them up a bit more (pump end) and it stopped doing it.

citronut · Post by **citronut** » 22 Apr 2011, 12:07

one of my customers had aufull prob's for quite some time startting his berlingo,

on one visit to me to check it i found fuel around the base of the primmer plundger, this being part of the filtter houseing i fitted a new one at around 80 quid or so,

this still did not fix the fault,

eventualy he was recomended to a diesel specialist, who found the fault to be a one way valve either not sealing fully on the fuel feed or return at the fuel,

so the fuel was syphoning back to the tank every time he turned the engine off,

regards malcolm

Post by **Peter.N.** » 22 Apr 2011, 15:24

Hi Paul

As already mentioned leaky leak of pipes will allow air ingress on the Bosch set up. If you can park on a very steep slope so the fuel tank is above the engine, you should have a fuel leak where the air is getting in.

Peter

spider · Post by **spider** » 22 Apr 2011, 15:25

Ah, I had forgotten about that even though I had that problem too. It took a while and a bit of headscratching (including replacing the filter assembly with a third party one and bypassing / making a new heater) A couple of non return valves from Ebay 'fixed'.

I fitted mine one just before the pump inlet (about two inches away) and the other at the top of the bulkhead before it moved along to the filter.

I figured the one before the pump would stop that issue and the one in the highest point of the line would stop any syphon effect.

Did not have any problems after that at all.