locating return line to fuel tank on xantia 1.9TD bosch pump

falling-out-with-my-car · 05 Mar 2010, 00:33

Hi, Id like to be sure that I have got the right line as the return line to my fuel tank as I would like to clear it with an air compressor because I fear it may be getting blocked by my using veg oil as fuel, can any one point to a diagram or the correct pipe line on the bosch pump please?

regards, N.

Xaccers · Unread post by **Xaccers** » 05 Mar 2010, 00:42

If memory serves Nigel, on the right hand end of the pump (where the injector pipes come out), above them is a black metal spiggot which bends towards the back of the car.
The return pipe slips onto the spiggot.

Unread post by **Dommo** » 05 Mar 2010, 11:05

That sounds about right Xac. Find the leak off pipes from the injectors, one will go back towards the fuel pump, it attaches to the return line on the fuel pump so you'll know when you've found it.

evilally · Unread post by **evilally** » 05 Mar 2010, 13:59

Not usually the return line that causes issues. More usual for the strainer in the tank to get clogged, or parhaps the line into the injector pump. You can tell the 2 lines apart as the line into the pump will have the primer bulb on it.

Unread post by **KennyW** » 05 Mar 2010, 17:14

Nigel,

Here is a photo of my pump and the return line is circled.

click for larger image
I hope this helps

Kenny

falling-out-with-my-car · 06 Mar 2010, 10:17

I'm sure I read somewhwere that running neat veg can block the return line because it is not under pressure esspecially over night in freezing temperatures but thinking about it the returnning fuel would be pretty hot and should clear the return line even if it was blocked, what do you think, is it worth checking before problems may occur or is it definately a non-issue to the FCForum for those who run straight veg oil using A bosch pump on a 1998 xantia TD?

regards Nigel.

Unread post by **CitroJim** » 06 Mar 2010, 10:24

I've seen the return line blocked on a car running veg for an extended period. It made the pump leak like a sieve and it took a 100psi air-line to clear the blockage.

Hot oil will polymerise (turn to a plasticky goo) over time. To see this, take a look at an old frying pan! This is what will block the line eventually I believe.

I've also seen the start of polymerisation in pumps I've stripped that have been running veg.

falling-out-with-my-car · 07 Mar 2010, 10:15

Jim,

this has been worrying me of late, because my dads Mk1 xantia Bosch pump showed signs of leakeage breifly on veg, once he put a tank of diesel in the car the Bosch pump re-sealed its self and has remained sealed ever since fortunately.(perhaps adding 7% petrol to the oil has made the pump work a little less hard) I am definately on the route of building some high heat fuel heaters this summer I want to raise the temperature of the veg to at least 150 degrees F before it enters the pump.

It is probably worth spending the money doing this esspecially when the pump struggles so during the winter months on a cold mornning.