Hdi not starting occasionally

[aaron_one]

Hi guys, for the past few days the 306 has been iffy starting up, I wait for the plugs to warm and I've owned a couple of hdis but this hasn't ever happened before. It fails to start and then if I try again it starts, I'm worrying that one day it just won't start! It's had a recent service, the basic oil, oil filter, air filter and fuel filter but I did notice the gold ring wasn't there when changing the fuel filter, not sure if this matters at all? I never seen the glow plug light on but it briefly flashed when I started it up last.

[Poodle]

Need to get it on diagnostics really, but it's probably lift pump or immobiliser/ecu related if it's starting second time.

[aaron_one]

One thing I didn't mention is the alternator is dodgey, I'm currently buying one off a member of the forum. I hope it wouldn't be the ecu I've just had it remapped by prosteve and he checked it before and after with diagnostics

[Toms306]

Glow plugs shouldn't cause you an issue, they're not needed to start a HDi. Does the pump prime when it doesn't start or not?

[aaron_one]

I can't hear a pump sound at all if I'm honest

[Toms306]

Hmm, I'll suggest a hearing aid then. But seriously, the lift pumps aren't quiet, you should hear it whine when you turn the key to ignition. If it isn't when it doesn't start then it's most likely the pump or the brown relay at fault.

[Magenta Sunset]

no gold ring in filter? I be thinking that's a missing 'spring washer' which holds the filter down under the cap.

[aaron_one]

I can hear the whining noise but I'll keep an eye out when it doesn't start next time. Is the spring washer needed?

[Magenta Sunset]

as I recall, it keeps everything in place. goes on top of the filter followed by the rubber o-ring for the cap
could it be a possible air leak?

[Piggy]

Yeah you need that brass O spring thingy

[aaron_one]

I've had a look around but can't find one, would I have to buy the actual housing all over again?

[Magenta Sunset]

vaguely recall may come in box with new filter - - - anyone care to confirm?

[Jimmy-hdi]

think you'll be best off plugging diagnostic in and read any fault codes if theres any

[aaron_one]

I replaced the fuel filter a week ago but nothing was in there :/

[Poodle]

I'd be surprised if it was the ecu at fault then. Especially since i now know you changed the fuel filter a week ago, as this is classic fuel pressure problems. Did you use a genuine/high quality aftermarket filter? Could be not flowing enough if it's not a decent one. Could be muck finding its way past the filter if you haven't got that spring washer. Did you drain the filter housing when you changed the filter? If not that could have also let some crap through into the high pressure system.

[aaron_one]

I drained it yeah, I'll have to find a washer somehow and see if that sorts it. No idea where to get one, can't find one online with places such as euro car parts

Failed to start again this morning, when I turned the key to ignition, I have to admit I only heard the light whirring of the fan inside the car, I couldn't hear anything else

[Magenta Sunset]

tried local pug dealer? (look-up microfiche)

[Toms306]

I think they've moved on a bit from microfiche these days.

I can post you a brass ring if my HDi breaker still has one.

If the lift pump isn't prolong though, you'll have no start anyway.

[aaron_one]

That would be great if they have one, I live in the stigs of Oxfordshire and there aren't any hdis about! Pm me if they have a ring and if obviously pay postage etc

[Magenta Sunset]

one thing to remember,
when you've got the spring in the top, it will be very stiff to fully tighten.
so, if you don't have a 6-sided spanner, I strongly recommend using a strap-wrench around the lid.
I do, works every time.

[aaron_one]

Thanks for the heads up, I've got a strap wrench so I'll use that

[aaron_one]

Yeah it just didn't make a sound when trying to start it. Does that mean it's the lift pump? Also what exactly is the lift pump?

[Magenta Sunset]

the lift pump is the low pressure pump the sits in the tank. under the O/S rear passenger seat.
when you turn the key (window down) you should hear a short whirring sound. a bit like your washer jet pump.

[Toms306]

I'm going over to the breaker later today so will check then.

As above, the lift pump 'lifts' the fuel from the tank and sends it to the high pressure pump. If it doesn't prime when you turn the key, no fuel will leave the tank. They're usually quite loud, shouldn't need the window down, but keep the fans off (never fully off on 306s tbf) ad radio off, lift up the rear seat base behind drivers seat and you'll be almost deafened by it.

[aaron_one]

Yeah there's no sound then, how easy and expensive is that to replace?

[Toms306]

It may not be that at fault, could be the relay that controls it.

No idea what they cost new, I do have both used pump and relay from the breaker for sale though.


Can someone confirm immobiliser doesn't cut fuel pump on these? I'm pretty sure it cuts injectors and that the pump still runs though?

[aaron_one]

I'll check again later and I'll let you know, completely in the dark about these two parts though no idea how to fit them or even get to them

[Toms306]

Lift pump is easy, lift up rear seat base and pop out the black plastic cover (hardest part of the job!!). Then it's there lol... You can test it by putting a direct 12 volts to it - if it primes every time then it's the relay at fault. If it's still not priming, it's the pump at fault. To replace it you just unplug the power plug and pop off the 2 fuel pipes. Then remove it's ring and pull it out. Easy enough but the more expensive part.

Relay is a bit more difficult to access and is bolted behind the ECU which is behind the battery.

[aaron_one]

Would a 12v small battery and a couple of wires be good to test it? Could do that tonight to see.

[Toms306]

As long as it's 12v yeah that'll work. There are 4 wires on the pump, 2 for the fuel gauge and 2 for the pump, so you'll need to find out which are the pump wires - I think it's the middle 2 but hopefully someone on here can say as I can't remember off the top of my head lol.