406oc.co.uk

Just been looking at a 307 1.4 hdi with a lift pump that won't turn off even when the ignition is off. Starts fine but engine cuts as soon as revs drop presumably over pressure at the HP pump. Any thoughts?

Maybe a faulty relay, (contacts welded)?

Can't see why it would give high pressure with the engine running. The lift pump normally runs for a few seconds to supply enough fuel to start the engine, then restarts and runs continuously all the time the engine's running.

On the basis that there's usually only one fault, I think I would concentrate on why it's stopping - any fault messages to help?

Not had planet on it yet, any idea where the relay is located?

Engine fusebox, probably.

Maybe you can look it up here: http://petrila.org/repair/index.htm

Just been looking in Sedre, dear god, how many possibilities? I think I'd need a vin to stand any chance (and I sure hope it's not in the BSI like my guesswork brought up...)

On further examination it appears I'm a bit of a tool!
The 1.4 HDI 70 engine has a priming bulb and no lift pump!
I'm now assuming the HP regulator is measuring low and calling for more and more fuel hence the overly high pressure through the lines??
Strangely unplugging the in-tank gauge cuts the pump from working balls out and the engine runs better with less stalling

Next step will be changing the regulator on the rail I think

I have a feeling you should do some diagnostics (fuel pressure maybe) before you start the replacing parts game

gumby6371 wrote:Strangely unplugging the in-tank gauge cuts the pump from working balls out

The tank sender is part of the pump, on 406s anyway...

It will get a session on planet before any parts are purchased

It only twigged when I was looking at the fuel tank area on service box and it listed it as 'gauge no pump', the priming bulb in the engine bay was a small clue but I completely missed it!

gumby6371 wrote:Next step will be changing the regulator on the rail I think

The regulator fits into the HP pump, the gubbins you're looking at is the rail pressure sensor.

Cheers Doggy, hopefully Planet will pin it down a bit further.