mjb wrote:I think you're left with a lack of fuel. I'm sure we've seen instances here in the past where someone's had an air leak in fuel lines causing fuel to seep back towards the tank? Would turning the ignition on a few times before trying to start in order to prime the fuel system prove/disprove this theory?
Yep, possibly. The fuel filter is about 20k miles old - perhaps this is one of things to change first. Could also be a lift pump? Though I do hear it humming when I turn the key on.
Will give the suggestion of turning the key a few times before cranking over a go.
Did this make a difference? Wouldn't you need to turn the ignition on and wait a few seconds for the low pressure pump to prime the system? It still sounds likely.
My 407 is similar but not as bad -- always more cranking on the first start of the day. It has a priming bulb, however.
Welly wrote:I'm wondering if the fuel pressure regulator on the end of the rail is causing problems i.e. it's not letting the fuel rail get up to full pressure (might account for power loss sometimes) does the engine run-on sometimes when you switch off?
It would be nice to kill two birds with one stone. The engine stops as instructed - it doesn't run-on. At least it never happened. The power issue has been happening for months now whereas this has only been happening over the past few weeks. The power issue doesn't seem to have gotten worse (or better)...related? Don't know.
Will definitely change the fuel filter as that was on the list of things to do anyway.
Could the in-tank pump be starting to fail? It doesn't seem to make a difference if I turn the key to ignition a few times before cranking either.
Glow plugs are definitely getting power. Measured with multimeter and can hear the relay click.
Welly, where's the fuel pressure regulator? Is it on the common rail or on the end of the HP pump? A chill has gone through my bones - could it be the HP pump failing slowly?
Maybe PP2000 would be a wise investment just to see what's what....
The pressure regulator is in the HP pump, (can be changed separately). It regulates the HP pump output in a continously variable manner under control of the engine ecu, based on the fuel pressure measured by the sensor on the common rail.
PP2k and tell you the set and actual fuel pressures, plus the amount of current supplied to the pressure regulator.
There is no pressure sensor for the LP side, but a healthy lift pump will make the filter lid 'bulge' a little when you turn the ignition on.
2002 HDi 2.2 Exec Estate, (2008-12) (wonderful)
2003 HDi 2.2 6-speed Exec Estate (2012-19) (also a gem)
2009 Citroen C5 2.0 HDi VTR+ Estate (godawful heap)
2008 BMW E91 330i touring (great fun - murdered by a reversing SUV)
2007 BMW E91 325i touring (slower smoother quieter)
When my Lift Pump was crapping out it was making a very low pitched 'grumble' almost a hammering sound and used to stick (not deliver any fuel) and the car wouldn't start without me running round the back and twatting the tank with my fist. I suppose it's possible the LP is getting slow, you'll know more when you whip the old filter out and look for metal swarf in there.
I'm not sure about the fuel pressure reg now as Doggy's thrown me a bit, I though there was a regulator on the rail which holds fuel pressure and also allows fuel to return to the tank when there's no demand, I might be wrong now.
Cars in my care:
2021 Kia Spottage 1.6 Pez Turbo Dual Clutch Gearbox Trickery
2013 Renner Twingo - donkey work
Welly wrote:When my Lift Pump was crapping out it was making a very low pitched 'grumble' almost a hammering sound and used to stick (not deliver any fuel) and the car wouldn't start without me running round the back and twatting the tank with my fist. I suppose it's possible the LP is getting slow, you'll know more when you whip the old filter out and look for metal swarf in there.
There are always some "gold bits" at the bottom of the fuel filter housing in the past. Thought they were signs of a failing HP pump but since there were no ill-effects, I ignored them. Had the same in 2.1TD.
I'm not sure about the fuel pressure reg now as Doggy's thrown me a bit, I though there was a regulator on the rail which holds fuel pressure and also allows fuel to return to the tank when there's no demand, I might be wrong now.
The fuel is returned from the injectors themselves, as far as I am aware....?
The arrangement welly describes is what you get with petrol injection systems, where the rail pressure is in the region of 3 - 5 bar. The pump delivers as much as it can and the regulator allows the excess to return to the fuel tank.
The HDi system doesn't regulate in the same way, it only generates the required pressure so there is no excess.
You're quite right that fuel is returned from the injectors, this is necessary because the electromagmetic valve at the heart of the injector could never operate under the differential pressure of up to 1350 bar on one side and virtually nothing on the other. To get round this, HP fuel is delivered to two chambers in the injector - one to be injected and the other to counteract the pressure of the first. when the injector 'fires' fuel from the first chamber is squirted into the cylinder, that from the second is released into the leak-off pipes and eventually back to the tank.
2002 HDi 2.2 Exec Estate, (2008-12) (wonderful)
2003 HDi 2.2 6-speed Exec Estate (2012-19) (also a gem)
2009 Citroen C5 2.0 HDi VTR+ Estate (godawful heap)
2008 BMW E91 330i touring (great fun - murdered by a reversing SUV)
2007 BMW E91 325i touring (slower smoother quieter)
To try and get to the bottom of this quicker, I decided to buy PP2000.
Now, will this ONLY work in Windows XP or will it work in Windows 7 under XP mode? Not really a problem as I have two XP laptops gathering dust but they are quite old and annoyingly slow so might need to reload XP from scratch on those.
I've only ever used XP, (but some others have found ways with newer kit). I would go for one of your old laptops and keep it just for this, it's a very undemanding application and will run on just about any relic.
(I invested a whole £27 in replacing mine last year).
2002 HDi 2.2 Exec Estate, (2008-12) (wonderful)
2003 HDi 2.2 6-speed Exec Estate (2012-19) (also a gem)
2009 Citroen C5 2.0 HDi VTR+ Estate (godawful heap)
2008 BMW E91 330i touring (great fun - murdered by a reversing SUV)
2007 BMW E91 325i touring (slower smoother quieter)
Mine almost didn't start this morning. Kept spinning and spinning... until AIRBAG FAULT came up on the MFD. I am now more and more veering towards it being the battery as definitely turns it over slower first thing in the morning than after a short drive, where the electricity will have been replenished by the alternator. It starts straight away if I turn the engine off and back on after a short run... but still turns over for a while (but not as long) if I try restarting it after the first start.
I don't have a battery booster/charger so can't test the battery theory. Perhaps, I should go to a motor factors and ask them to test it as suggested here. How do they test it? Would it give true results after a run?
PP2000 should be here next week, so that's another thing to do. I also, inadvertently, bought a fuel pressure regulator on eBay. I put a bid on it, then thought I should way but forget to retract the bid. So it's mine for £14....
Alex, a dodgy battery springs up all sorts of gremlins - a new one should sort it them out
2003 2.2hdi estate - mine 1998 Volvo 940 auto estate - also mine 2019 Citroen C3 something - the wife's PP2000 user, can help with faults / diagnostics in the Bournemouth area.
What's the correct battery type? It's a minefield over there. At the moment, I have some Bosch one I bought at the start of 2010... though need to open the bonnet to check the exact type.
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