406oc.co.uk

Hi everyone,

I'm posting this on behalf of a friend who owns an 02-plate (2002 model year) 406 Estate TD as he's not got internet access and is thinking of scrapping his 406 for a fault that his garage can't seem to fix, and may have caused.

(Sorry for the long story)

He took it in to get a faulty fuel gauge repaired and the garage replaced the sender and fuel pump unit in the tank. All appeared well until the next day when the priming bulb exploded and about 20L of diesel was pumped out onto the road.

He thought that it was just a perished primer (the car's done about 220k miles) so had it replaced. Sadly the next day exactly the same thing happened again - the primer bulb failed and there was diesel everywhere. Other than this fault, the car runs perfectly, no smoke, great performance.

I've done a search of the Interent and also on this forum to see if anyone else has experienced the same thing, and so far nothing has come up.

I'm wondering if there's a simple explanation for this: e.g. I think this car has the siemens fuel system (as it has the priming bulb) so have they fitted the bosch pump (is it a higher-pressure pump?) or something silly like that? I know it's possible that a new pump might show up a pre-existing fault (e.g. a blockage in the fuel return line or something) but maybe there's an obvious answer.

Thanks for any help you can give - funds are a little tight so an easy DIY fix or even some pointers to give the garage would be very useful.

All the best,

Simon R.

I think you've hit the nail on the head, Simon.

406's have a combined level sensor / strainer / lift pump unit. On Bosch equiped cars this includes a lift pump, whereas Siemens systems don't they rely on suction from the engine-driven HP pump to draw fuel from the tank, (with a priming bulb, in case it doesn't). Bosch systems don't have the priming bulb.

The garage has obviously fitted a level sender / lift pump unit for a Bosch system to his car. Take it back & create hell over it.

FWIW, you can buy a new replacement sender unit from Eurocarparts, for a Siemens system for about £60, it's about £100 for one with a lift pump......

you wouldn't have thought there'd be power there for the pump but i guess there must be

what a stunning piece of cockuppery i think i'd be scared to take it back there in case they swapped the glowplugs for spark plugs or something.

seems you can get thicker than a quick fit fitter...

I think the lift pump delivery pressure is about 3 Bar, which sounds like rugger ball compared to the HP pump, but 40-odd psi is a lot for a priming bulb

My priming bulb normally feels quite loose!

Thanks for the replies, gents - looks like it'll be a reasonably easy fix in that case...

It'd be a shame to scrap the car after such a relatively simple fault but after losing control of it (due to diesel all over the road under the wheels) and about £100 worth of fuel wasted I think he's lost confidence a bit. Afterall, I'm given to believe that at 220k miles that engine on one of these things will nearly be run in!!

I'll get him to relay this info to the garage...

Cheers

Just a quick update: My lucky guess and your confirmation was correct!!

The supplier supplied the wrong pump when the garage gave them the VIN details so have agreed to supply a replacement free of charge and also pay for all the spilt diesel.

The garage owner (an independent one-man-band) is now busy repairing the mess and will also be out of pocket, poor chap.

Anyway - so to confirm, the wiring IS there to fit the wrong pump, so beware :-)