More questions on 1.9TD fuel air leaks.

[aerodynamica]

I am still having problems with the fuel system on the Xantia TD.

So far I have replaced the leak off pipes, the fuel pipe to filter connection clip and the 8mm fuel line from the filter top to the diesel pump. It was fine but this morning it almost cut out again and was really not willing to go. It never actually died though and nearing the journey's end it seemed ok if a little down on power.

A new diesel filter was fitted back in September and I have reseated and then resealed the filter housing including the thermostat thing at the lower side.

I can see absolutely no external sign of diesel getting out anywhere.

I notice that when I squeeze the primer bulb there is an audible slosh of fuel into the filter housing. It takes 4-5 full squeezes then the bulb goes hard - fully primed I thought. But wait a single minute and the bulb is soft again and will take a full 4-5 squeezes to prime to hard. It seems like the fuel is priming then internally leaking away somewhere. Or is this normal?

I don't know what it's supposed to be like as I don't know what a new car should do. I would expect the primer bulb to stay hard after priming for a long time after manually priming and at least until the thing is started. Is that right?

I just can't see any new source of leaking.

I also want to bypass the plastic filter but of course the inlet pipe is much wider than the outlet so need some sort of stepped connector. Has anyone done this and what did they use?

Any help greatly received !

[DickieG]

As the fuel line isn't under pressure it rarely leaks fuel but will let in air as the fuel level within the fuel line is higher than the tank level, apologies for the pun but the prime suspect if the fuel primer bulb. The behaviour you describe of the primer sloshing then going soft quickly after being primed is usual. Try parking the car downhill if you can as if this improves its starting then it confirms there is an air leak.

[aerodynamica]

Thanks, it's funny I had been parking it down hill but now it's raining and my sunroof can't cope with the rain when it's pointing downwards... I know! I asked about the front drain tubes before and I even recall that you don't blow them out from the top in case the pipes disconnect BUT I keep forgetting where the lower exit for the drains are..

As for the priming issue; it seems that the car starts and runs until I get to a set stretch of road about a mile or so away and this is its cut out zone. It seems to be running on the fuel in the line and diesel pump and then reaches an air bubble at this stretch of road.

So this bulb - it will have a sort of check valve in it that has presumably worn out. But the air getting in? could this be the join at the ends of the bulb? It does look like the rubbish 'pinch' type of clip it uses.

[robert_e_smart]

The body of these bulbs also deteriorates. I have seen them perish before. Try a new one, or fit a one way valve s well to stop the fuel running back to the tank.

Have you been using clear pipe to try and identify which sections have air ingress?

[DickieG]

Hmm, this stretch of road you mention is it where you'll be putting a greater demand on the fuel line as in accelerating? I'm wondering whether you have a build up of crud on the fuel strainer pick up in the fuel tank, I'll post a photo of one I found to give you some idea of how bad this crud can be.

[aerodynamica]

Hi Robert, no I couldn't find any clear pipes when I replaced them - just black pipes. Well, it's been a hellish day for many reasons including the 'will it make it' journey this morning so I'm shattered so night folks!

[robert_e_smart]

The Algae that grows in diesel is a nuisance. It amazes me how the cars can still run with so much of the gauze covered in crap.

[aerodynamica]

Hmm, this stretch of road you mention is it where you'll be putting a greater demand on the fuel line as in accelerating? I'm wondering whether you have a build up of crud on the fuel strainer pick up in the fuel tank, I'll post a photo of one I found to give you some idea of how bad this crud can be.

I'm back!
Hi Richard, no, it's the opposite: it's a stretch of road that having just left the town limits, gently descends for about a kilometer and ends in double lights. It sees you generally notch it into 5th and cruise down. If I am stopping at the lights, as I declutch to change down it often quietly cuts out. I roll up to the stop line and lights off, heater fan off switch the heater plugs back on, wait, crank over and after a good 10-15 sec of cranking it splutters to life and then is fine for the remainder of the 21 mile journey.

Today however, it was already losing power in little twinges on the cruise down to this stretch. Keeping the revs up by doing the stretch in 4th seems to be the only solution so far.

[aerodynamica]

Still, I'll certainly be looking at the pick up gauze in the tank. It can be accessed via a plastic bung under the rear seat right? You need to be careful with the pipes in case they fall down the side if I recall.

[robert_e_smart]

Thats it, I'd be more careful to not break the threaded sealing ring that holds the pick up unit in the tank than loosing hoses.

[aerodynamica]

Threaded ring? I've not investigated this - I'm more familiar with what CX and GSA had: a pick up/ sender unit that slotted into the top of the fuel tank and had a locking ring around it that you used a small drift to tap round.

[DickieG]

Crud on the fuel pick up

[Xaccers]

Put cable ties around the pipes to stop them falling down the side of the tank.
Another hidden place of air ingress is the white thermostat on the driver's side of the fuel filter housing.

[aerodynamica]

Good grief that's bad. Well, it's coming out!!

Xac, I'm hoping to bypass the entire fuel filter housing for a period. I have used a stretch of rubber glove cutting jubilee clipped to seal off that thermostat at the side purely temporary to try and eliminate it from the inquiry - still got the probs though!

[aerodynamica]

Cheers all, I'll get on the case. night!