200 TDI injector pump

[drmike]

I have had a growing problem with the turbo boost kicking in later and later and suddenly – as if a switch had been turned on. Now the boost fails to happen at all. I have checked all the usual suspects leaks etc.

Anyway after much looking I took the top off the boost pump and exposed the diaphragm. I pressed down on it and it didn’t move to the extent that I wondered if it went up not down! One mighty shove later and it suddenly gave way and moved. It felt like something was gummed up if you know what I mean and gave way under pressure. Not a snap but like pulling a sticky toffee off a chair.

I haven’t taken the diaphragm off yet as I’m not sure how to do that.

What’s the probable cause?

I’m hoping to find some build up of gunk somewhere

I fear it’s the injector pump failing

Any ideas?

Mike

[Porny]

Mike,

Sorry I haven't replied to your email via difflock.... been having a few computer problems.....


Various causes....

Will take a while to write this post.... will be right back


Ian

[drmike]

Ian

I have made considerable progress.

The diaphragm was clearly sticking, it took considerable force to make it move downwards so the poor old boost pressure would have struggled.

To me this implies the rod attached to teh diaphragm is probably rusted or in some way dirty.

I have applied copious WD40 and it now moves freely but won't come out.

I think it might work now but ...

I think the reason it won't come off is because the rod it is meant to operate is seized and is trapping the taper against itself.

Therefore I think my problem is freeing off teh rod the tapered end bears against.

Deep breath. I further believe I can get at this thing via a hex headed bolt that hides behind the throttle arm which has all the springs and things on it. I have been advised I must be very careful to mark the throttle arm before I remove it - although I have no idea why.

I am hoping that if I leave evrything soaking in such WD40 as I can get in there it may free off in the morning.

I'm learning! I really need to get this done by Sunday as I have a trial then.

Mike

[Porny]

I’d agree….

By the sounds of it the operating pin that slides onto the concentric shape of the diaphragm is partially seized (which does happen)...
If you lift up the rubber section of the diaphragm, copious amounts of WD40 should help.

Then you ‘should’ be able to gently ‘work’ the diaphragm out.



The pin….

Deep breath. I further believe I can get at this thing via a hex headed bolt that hides behind the throttle arm which has all the springs and things on it. I have been advised I must be very careful to mark the throttle arm before I remove it - although I have no idea why.

Not sure about that… see pic:

Pin is part no: 4

This cannot be removed without stripping more of the pump down.

[drmike]

I see what you mean about getting at that pin. Maybe I misunderstood the advice I was given.

Is M1 and pivot that lets 3 move 4?

I need to free off 4 - well at least I think that's the case as I think 4 is stuck and won't let me withdraw the rod as it is trapping the taper.

What lubricates the innards of the bits around M1?

To quote the advice I was given:

'Basically you need to remove the throttle lever, after marking EXACTLY where it is, then in the body of the pump, there is an allen key bolt head. Remove this and squish wd40 into the hole and work the lever inside back and forth. You will need the diaphragm out for this.'

I can see the pretty large allen key bolt head but looking at your diagram it's not clear to me where it fits in!

My issue for now is that the diaphragm won't come out but I'm hoping that WD40 and plus gas will work their way down there.

Many thanks for the picture it was justw aht I was looking for and couldn't find.

I'm learning but I'd really like to fix it!

Mike

[Porny]

I see what you mean about getting at that pin. Maybe I misunderstood the advice I was given.

Is M1 and pivot that lets 3 move 4?

I need to free off 4 - well at least I think that's the case as I think 4 is stuck and won't let me withdraw the rod as it is trapping the taper.

What lubricates the innards of the bits around M1?

To quote the advice I was given:

'Basically you need to remove the throttle lever, after marking EXACTLY where it is, then in the body of the pump, there is an allen key bolt head. Remove this and squish wd40 into the hole and work the lever inside back and forth. You will need the diaphragm out for this.'

I can see the pretty large allen key bolt head but looking at your diagram it's not clear to me where it fits in!

My issue for now is that the diaphragm won't come out but I'm hoping that WD40 and plus gas will work their way down there.

Many thanks for the picture it was justw aht I was looking for and couldn't find.

I'm learning but I'd really like to fix it!

Mike

M1 - Pivot for stop lever
3 - stop lever
4 - guide pin

What lubricates the innards of the bits around M1?

Not sure, probably just a lithium based grease (though I may be wrong)

I really one one of these pumps to take apart!!!


I think what you've been told, refers to removing the full load adjusting screw (part no 10) and then giving everything a good spray inside.


Ian

[drmike]

I was wondering if it was grease as I think that can either go hard after some years of service or if it gets wet and muddy goes hard as well which is presumably what's happened here.

No 10 doesn't look like what I am proposing to remove but I think in general terms the idea will be to take out this bolt with the allen head and squirt WD40 in there. I'd rather do it a bit better and get some decent lubrication in there for fear of the problem returning but we'll see.

In fact if 10 is the full load screw that's the other side to what's being suggested. Isn't that the screw that's under where the pipe goes into the cap from the turbo end of things?

I think it's more probably not on your picture at all - incidentally where did the picture come from?

Mike

[drmike]

OK so now I'bve reached ths stage where I have to remove the throttle assembly from the pump.

This assembly sits on a splined shaft and must be replaced onto the same splines.

I can't see any convenient and reliable way to mark this - can anyone advise please?

Mike

[drmike]

Just for anyone's interest  I took the throttle assembly off reasoning I would get nowhere if I didn't. Much tipex all round to mark the position although there seem to be some radial marking on teh arm whcih I hadn't seen last night..

Then the blessed plug with the allen head didn't want to leave but eventually I got that out.

But I seemed to be looking at the back of an arm so squirting WD really just splattered it all over the place.

Plan B dribble plus gas oil down the shaft from the top and fill up the recess the rod on the diaphragm goes into with penetrating oil. Still no joy.

Then I thought well I have to move the pesky arm and I got a small drift and hammer and gave it a bop. It did move and then I had to force it back using the diaphragm. As you can guess it was lots of small steps, millimetres only and eventually out popped the diaphragm.

At this stage I could begin to really work the rod back and forth and it's pretty well freed up but I'm not totally happy that it's not still got dirt in there. However, I can't rotate it (nor get it out) so I'm stuck with moving it a very small amount to ease it off.

I have some liquid grease in a aerosol can which I think I'll use as the final lubricant but I'm not sure how much more waggling I should do.

Will it work though? I see no reason why not but since when has that mattered?

There's a moral here. If you lose all boost don't despair as it might just be seized up bits so don't rush to get a new pump fitted at huge coost.

Also there is a breather in the boost pump and that is probably what let the damp in that caused the problem so extend that breather I know I shall. It's the dippy little rubber cap with a spout near where the pipe arrives from the turbo. I bet loads of people just chuck that away!

I'd like to record my specific thanks to Andy at Allipsort who was really very helpful sharing his expertise freely. Top man and while I'm here top products I have one of his bigger intercoolers on the Disco and it works!

Mike - thanks to anyone who gave this some thought! I was VERY intimidated by getting into the pump.