Fuelling, Diesel injection, etc help/suggestions

Before the rebuild my Landy ran quite well. However, every now and then it would run REALLY well. Pulled much better than normally which created a more relaxed driving experience. Otherwise, you always felt as though you were pushing it really hard and it made it harder work to drive.
Anyway, since I got it back on the road I've felt it's been in the 'slower' mode. The Mrs uses it as her daily drive to work and this week reported it pulling REALLY well, so it must have been in slower mode. This has galvanised me in to trying to sort it out, I'm going to need help though!
I did nothing with the engine when I did the rebuild. The only thing that I did was flush/clean the intercooler.

I've been looking through existing threads on LZ and googling elsewhere too. I thought I'd make a list of possible issues and would appreciate you adding to the list of things to check.
So, in no particular order,
injectors
boost pipe from turbo to FIP
Turbo
FIP
Intercooler
Injector pipework
Turbo pipework
wastegate
Lift pump (already renewed this, forgot to mention that above)
fuel filter
air filter

To recap, it drives ok, but occasionally I seem to get it's true potential. I'd like to get the true potential all the time.
Anything else I should consider and what is worth checking first given the symptoms?
Cheers.

Mine seems to vary a bit too, however I think mine seems to be affected by general weather conditions i.e. damp/dry/hot/cold. Need to do a bit more record keeping to see if there is a trend. I use the same fuel (Shell standard) so hopefully can eliminate different fuel blends although I do believe summer and winter fuel differs.

Our disco came with a layer of crud in the fuel tank - clearing it out had real benefits.

Did you look in the tank on your build? Might have shaken something that is intermittently blocking / unblilocking the pickup.

Also maybe make up a custom fuel line with the correct banjos but a bit of clear nylon, just to make certain you don't have a tiny air leak.

Kwakerman said:

Mine seems to vary a bit too, however I think mine seems to be affected by general weather conditions i.e. damp/dry/hot/cold. Need to do a bit more record keeping to see if there is a trend. I use the same fuel (Shell standard) so hopefully can eliminate different fuel blends although I do believe summer and winter fuel differs.

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Looking for patterns is a great idea. Mine's been fairly sluggish since it went back on the road last July, so it's had summer and winter driving and both have been the same. Neither I nor the Mrs can think of any unusual variable. I've just asked her if she put different fuel in and no.

julianf said:

Our disco came with a layer of crud in the fuel tank - clearing it out had real benefits.

Did you look in the tank on your build? Might have shaken something that is intermittently blocking / unblilocking the pickup.

Also maybe make up a custom fuel line with the correct banjos but a bit of clear nylon, just to make certain you don't have a tiny air leak.

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New tank, Julian. I used the old fuel lines though, so I could put new fuel lines on the list. Cheers.

Something interesting has happened.
The Mrs has reported the Land stalling several times. Reversing off the drive on the way to work first thing. Pulling away in the car park from work, so engine cold each time. Then, she says, restarting easy but when pulling away it suddenly lunges forward when the power suddenly comes on.
Does this sound like a familiar symptom to anyone. Perhaps FIP going west. I'm not sure how they work, I know there's a rubber diaphragm involved.

Wont be the diaphragm as that only comes in to play when the boost pressure is up (not reversing out of a drive), sound more like air in the fuel lines or leak-off pipes leaking air in.

Kwakerman said:

Wont be the diaphragm as that only comes in to play when the boost pressure is up (not reversing out of a drive), sound more like air in the fuel lines or leak-off pipes leaking air in.

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Cheers, Kwakerman. I've no idea what else can go wrong with them. It's looking like a learning curve might be coming around the corner.

Al2O3 said:

Cheers, Kwakerman. I've no idea what else can go wrong with them. It's looking like a learning curve might be coming around the corner.

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If you still have the original leak off pipes fitted then they will be past their best and due for replacement, a quick and easy job which may sort your issue out.

Kwakerman said:

If you still have the original leak off pipes fitted then they will be past their best and due for replacement, a quick and easy job which may sort your issue out.

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Cheers, mate. I'll investigate

The fuel leak off pipes are not showing any signs of leaking, if you know what I mean! I'll still buy some new pipe though.

The Mrs has reported more symptoms tonight which, hopefully, might indicate something more clearly to you peeps. My fingers are crossed.

• Very lumpy this morning when she started it up. It wouldn't tick over on it's own without her putting a bit of pressure on the accelerator. She said it would have cut out. She had to sit and throttle it to get it warmed upIt was -2/-3 here, but that shouldn't make a difference.
• White/grey smoke out of exhaust until it's warmed up a bit.
• She thinks it's using more fuel, but it's early days on that for checking. That might be auto suggestion from me asking that question last week.
• Even when warmed up a bit it's not pulling away very well at first, but then lunges forward. Like a delayed throttle response. This seems to be more noticeable than it was before. She has a tricky junction to pull out of at work where she has to turn right across a narrow road which cars speed down.

Any thoughts very welcome.

Cheers.

Stabbing in the dark here but keeping thread alive. Could one of the injectors be blocked restricting fuel to one pot intermittently.
( I,ll get my coat)

mick the builder said:

Stabbing in the dark here but keeping thread alive. Could one of the injectors be blocked restricting fuel to one pot intermittently.
( I,ll get my coat)

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Not sure, Mick. I've been reading @Saint.V8 thread on his timing issue. Mine smokes the same colour, but only for a minute or so. The fact that it's getting 'lumpy' when started in the morning (this morning had to be revved to keep going) is making me think injector, but I don't really know.

Al2O3 said:

Not sure, Mick. I've been reading @Saint.V8 thread on his timing issue. Mine smokes the same colour, but only for a minute or so. The fact that it's getting 'lumpy' when started in the morning (this morning had to be revved to keep going) is making me think injector, but I don't really know.

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I'd first start with looking at the FIP timing....(not just because I have a current thread about it either ), but FIP timing is simple enough to check and can tell you a lot...and is one of the most common causes of smoke.

Just to FYI as you were asking about the rubber diaphragm etc....Now I am no expert but this is a rough explanation on how the pump works.

A top the pump is what is known as the Automatic Fuel Control set up.... under the cap is a rubber diaphragm that is connected to a plunger, the diaphragm is held in its upper most position by a spring that is under the diaphragm pushing it upwards, the spring tension is set by using a 'nut' on a threaded shaft....(this nut is known as the Star Wheel).

The Plunger has a particular eccentric cone shape to it and is to control Fuel Delivery Rate.

Inside the pump is a pin that is the Fuel Stop Lever.....this pin runs on the Plunger Cone section.#

The top side of the diaphragm is acted upon by the boost pressure from the Turbo causing the diaphragm to push down against the spring pressure.....as the diaphragm deflects, the plunger moves with it allowing the Fuel Stop Lever pin to move inwards (as it is following the eccentric part of the plunger cone) and increases the Fuel Delivery Rate as boost pressure increases.

The Diaphragm and Plunger can be rotated around so a different profile of the eccentric Cone is aligned with the Fuel Stop Lever pin - factory set is quite lean, it can be rotated to increase fuelling during boost.

The Star Wheel adjusts the pretension on the spring that pushes up against the Diaphragm. This can be adjusted to adjust when the Diaphragm and Plunger react to the boost pressure applied to the Diaphragm. Screw the Star wheel down to reduce spring tension and allow additional fuelling due to boost to come in sooner.....screw the Star Wheel up to increase spring tension and delay when the Plunger moves thus introducing additional fuelling later in the boost charge.

On the back of the pump is the Maximum Fuel Quantity adjuster, this sets the maximum fuel that can be delivered to the pump regardless of the plunger position.

Under a protective, anti-tamper cap is the Smoke Screw.....this is to set the amount of smoke when the engine is at idle or off boost. Screw it in to increase fueling (it pushes the Plunger down against the spring pressure) or screw it out to reduce fuelling.

The way the pump delivers is pressured charge to the injectors is for another discussion.......

Here is quite a good article about the tuning process.....

http://dividingcreekimports.com/TdiInjectionPumpTuning.html

There are also videos on Youtube about tuning the Bosch VE pump....makes interesting watching and reading.

Note: Adjust one setting, and you may have to adjust another.....our other 110 (the '91 Defender 110) uses a 300Tdi and I went through a few different settings of the pump, and she now runs sweet, smooth and powerful while not smoking any colour....

Remember Black is burnt fuel with not enough oxygen, White/Grey is unburnt fuel.....

Cheers, Saint.V8. I think that is a very clear start for me to begin getting my head around the complexities of fuelling. I'll do more reading and watching with the links you have given me. Thanks again.
Is it possible for one of the adjustments to move on it's own? Obviously, I'm wondering why there is a change in what's happening with the engine.

Have you changed the fuel filter yet.
No mention of it being changed.

Simple things first, as others have said clear pipe to check flow from tank, [no air] new fuel filter, lift pump working properly.

Yeah, bought a new lift pump and made the mistake of testing the old one when I got it off. Got a face full of diesel, cos it was still working a treat. Put the new one on though. Fuel filter was changed about 6k miles ago, but I'll change it again. I'll buy new fuel lines.
I'll do a search for checking and testing injectors.
Thanks for your thoughts guys, much appreciated.

Weather has been terrible this weekend and did not fancy standing on the drive in it, so I've not done any investigations.
I did pop out and stood in the rain to take a short video of the exhaust as she started up.


You can see how 'lumpy' the engine is when it first starts up. Takes a few minutes before it starts to run smoothly. When you first pull away in first it's very sluggish, then surges in to life, change in to second and it's slightly better but you still get a surge. Then it gets warmed up and starts to behave.I reckon the surge will be less noticeable in third anyway.
Does this give anyone any further thoughts?

Sounds like pump timing to me, as others have said it's easy to check, set engine to tdc, there's a slot in the flywheel which can be seen through the hole in the bellhousing. If you've got one, insert locking tool here. Whip small cover off front of timing case and you should be able to slip a 9.5mm drill bit into the locking hole of the FIP pulley.
If not, slack off the 3 10mm bolts, rotate pulley slightly using 22mm socket until you can slide the drill bit right through to lock the pump in place before re-tightening 10mm bolts. You can get cheap locking pins off eBay for a couple of quid to help with this.

300tditoy said:

Sounds like pump timing to me, as others have said it's easy to check, set engine to tdc, there's a slot in the flywheel which can be seen through the hole in the bellhousing. If you've got one, insert locking tool here. Whip small cover off front of timing case and you should be able to slip a 9.5mm drill bit into the locking hole of the FIP pulley.
If not, slack off the 3 10mm bolts, rotate pulley slightly using 22mm socket until you can slide the drill bit right through to lock the pump in place before re-tightening 10mm bolts. You can get cheap locking pins off eBay for a couple of quid to help with this.

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Cheers. I'll do that as soon as I get a chance. Unfortunately, I'm away for the next few weekends, but as soon a I get back I'll try that.
What can cause the timing to move?