HP pump leak

TD4 2006 70k miles
Hi, it's time for the Freelander to go wrong again!
Anyone got ideas about this one - The High Pressure fuel pump has started to leak at a rate of 1 or 2 drips per second. It leaks generally from the pump body which leads me to suspect a seal has let go, so a new seal kit should fix it. BUT here is the question> Why does it leak then the next time it starts it's completely dry when run for over 15 minutes then when started again it might decide to leak. To sum up, it randomly leaks badly or not at all, completely dry.
Part 2 – Has anyone rebuilt a CP1 HP pump? Anything special required apart from the sprocket extractor tool, any advise generally? Over to you, thanks in advance.

Hi, I have not changed one, my local garage did it because I didn't have time.

However, mine eventually blew the seal and forced diesel into the crankcase breather causing much smoke and the engine to run on after turning it off. Quite scary and it revved itself into a frenzy before I stalled it - so beware !

Your intermittent leak may be the fuel regulator adjusting for loss of pressure and reducing the fuel feed to prevent damage - just a thought??

Garage changed mine o.k - about 2 hour job with release tool.

Good luck !

Thanks for the info. I'll probably start this job next week. The intermittent bit makes me think that it might be an electrical fault sort of pressure regulator not regulating down enough then blowing fuel out of ? one of the pump cylinder heads (or all 3). It's gone out on a 4 mile test, dry when it started (or it obviously wouldn't have gone out) and dry at the end of the run. It does run great?

Hi.
Check out my website.
Andy.

Hi Andy, your website - just what the doctor ordered, spot on.

MoreWork said:

Thanks for the info. I'll probably start this job next week. The intermittent bit makes me think that it might be an electrical fault sort of pressure regulator not regulating down enough then blowing fuel out of ? one of the pump cylinder heads (or all 3). It's gone out on a 4 mile test, dry when it started (or it obviously wouldn't have gone out) and dry at the end of the run. It does run great?

Click to expand...

Unlikely - the fuel pressure regulator is like a 3-port valve, it constantly bleeds off fuel through a tank return to control the pressure in the fuel rail, at tickover more fuel will be being bled off than sent to the engine.

Hi Tannaton, 'the fuel pressure regulator is like a 3-port valve' fair enough that makes sense but what I was thinking is this – on the end of the common rail is the fuel pressure switch, does this tell the HP pump when to 'blow off' excess fuel to the return line if not what does or does the switch only report a low pressure condition? How is the over pressure controlled? This is acting like an electrical control fault, for 2 days now the car has been run about all over the place as normal and it is perfectly dry. Which is entirely opposite when it decides to leak, the whole of the pump body is wet and dripping. The next time it is started it could be nothing, perfectly dry, drive where you want no bother. If I'm going fix this I'd like to know I'm shooting in the right direction. I can't yet understand why it's so extreme good, bad, good etc. Seems to drive ok leaking or not. Still thinking!

The hp pump leaks when cold as a rule , when one of seals go , could not find the leak visually , local cowboy did mine a bosch service centre , source of replacement pump was dodgy , he had to replace it after 4 months which has been fine , touch wood since !

Update: First of all thanks for all the replies. The news is – it's done! Recap: The HP pump was dripping wet then bone dry for 4 days then dripping wet randomly. So that's it, I thought, it's off the road. The first thing to do with a job like this is to have a holiday, so I did that. Then I ripped it all down (using the special puller for the pump) and got the pump off. I had no instructions on how to rebuild the pump, just 2 Bosch drawings in exploded view (when I examined these drawings I found a few mistakes – Bosch unable to draw things correctly, what hope could we have after that!). I stripped and built the pump, made a nice job, reassembled everything and it runs beautifully. Along the way I did the breather modification, which needed a modification!?! (a location notch needed cutting) and found a broken wire to a sensor. Apart from an old Rave disc I used what was on Andy McIntyre's site, very useful take a look there. Thanks again everyone for your comments/suggestions. I am now going to look on ebay for a zipper conversion for the under tray as it seems to need to be removed every couple of weeks for some MOREWORK.