300tdi boost pin wear

Hi new to the forum and in need of help
I have a defender 300tdi auto and was having trouble with black smoke when I hit kick down or low end in 4th on the motorway (lack of power came with this), the injector pump has obviously been messed with in the past so I decided I would try and turn the fuel down, this is after I have replaced all hoses, injectors and intercooler, broke into the top of the pump to see if there was a boost pin fitted and there was, but when I pulled the pin I noticed that it has only been wearing in one spot, and here’s my problem, what would cause this? And would fitting a standard pin back on cure it?

Thanks in advance
Woolfy

Is that a hole?

Cheers

neilly said:

Is that a hole?

Cheers

Click to expand...

Pretty much yes

OK, very strange, as normally the wear is a line where the fuel pin has been moving against the boost pin.

Is the spring in place?

Does sound like someone has been playing, I would fit a std pin or a pin from a reputable supplier and see how you get on.

Cheers

neilly said:

OK, very strange, as normally the wear is a line where the fuel pin has been moving against the boost pin.

Is the spring in place?

Does sound like someone has been playing, I would fit a std pin or a pin from a reputable supplier and see how you get on.

Cheers

Click to expand...

Spring is in place yes, going to try taking the pin out of my 200tdi to see if that fixes it, will order a new pin as I’ll need it anyway, just can’t figure out how it could happen

1st - That hole / spot is at the top end of the slope (looks like it's been stuck in max setting
2nd - it should be a straight line up & down, where the pin moves with pressure from the diaphragm.
potentially it looks like it's been stuck in max fuel setting, despite boost pressure from turbo.
That's really weird.
It hasn't snapped the tip off the other pin that meets it at 90 degrees, has it?

exmed wayne said:

1st - That hole / spot is at the top end of the slope (looks like it's been stuck in max setting
2nd - it should be a straight line up & down, where the pin moves with pressure from the diaphragm.
potentially it looks like it's been stuck in max fuel setting, despite boost pressure from turbo.
That's really weird.
It hasn't snapped the tip off the other pin that meets it at 90 degrees, has it?

Click to expand...

Pin seems to be complete as far as I can see, I have noticed that after looking at my 200 and then looking at this there is a lot of diesel in the area under the diaphram

Woolfy96 said:

Pin seems to be complete as far as I can see, I have noticed that after looking at my 200 and then looking at this there is a lot of diesel in the area under the diaphram

Click to expand...

That area should be dry.

Cheers

neilly said:

That area should be dry.

Cheers

Click to expand...

+1
The most obvious thing is that someone has spun the star wheel so much, there is no resistance and the "boost pin is constantly down at it's max setting?
but that wouldn't explain why there is diesel in there.
How long have you been driving normally, before you noticed there were problems?

exmed wayne said:

+1
The most obvious thing is that someone has spun the star wheel so much, there is no resistance and the "boost pin is constantly down at it's max setting?
but that wouldn't explain why there is diesel in there.
How long have you been driving normally, before you noticed there were problems?

Click to expand...

Is it even possible to wind the spring down that much?? Maybe someone did a hack job and reduced the spring, seems very odd. Or has the off boost screw been changed to keep the boost pin in that position.



Cheers

exmed wayne said:

+1
The most obvious thing is that someone has spun the star wheel so much, there is no resistance and the "boost pin is constantly down at it's max setting?
but that wouldn't explain why there is diesel in there.
How long have you been driving normally, before you noticed there were problems?

Click to expand...

Converted it from a trialer Back to a truck and had these problems since I got it back on the road, only just started driving it daily the past month but I only really noticed the the smoke on the motorway (first big journey it’s ever done)

Sounds like someone has wound it to the max and beyond.

Cheers

neilly said:

Is it even possible to wind the spring down that much?? Maybe someone did a hack job and reduced the spring, seems very odd. Or has the off boost screw been changed to keep the boost pin in that position.
Cheers

Click to expand...

Intriguing....
If there was a leak in the pipe from the turbo to the injector, losing boost pressure, then the pin would not go down and the marking would be at the bottom of the slope, not the top.
If the boost pin is moving up and down as it should, with the changing boost pressure, then there would normally be a vertical wear mark on the slope of the pin.
this has confused me - especially the presence of diesel in the chamber?
I'm going to hunt for a tech drawing of the pump.

Update, just put a boost pin out of the 200 in it and ragged it round the block, pulled it to bits again and there’s now a fresh mark running the length of the pin in the position I placed it, I tried to match the angle of the standard pin to that of the aftermarket one so I wouldn’t have to change the fuel setting so I could test it, what I have noticed is the the mark it made is half the length of the mark made by my 200 which is standard with all the anti tamper things In place

Sounds like the spring has beeen wound right out. so it takes less turbo pressure to move the pin downwards ,

I reckon you have a knackered pin in there originally and I would fit a new hardened boost pin. Then look at resetting the pump as you want it.

Cheers

was the mark left by the fuel pin on the boost pin top or bottom?

Cheers

Woolfy96 said:

Update, just put a boost pin out of the 200 in it and ragged it round the block, pulled it to bits again and there’s now a fresh mark running the length of the pin in the position I placed it, I tried to match the angle of the standard pin to that of the aftermarket one so I wouldn’t have to change the fuel setting so I could test it, what I have noticed is the the mark it made is half the length of the mark made by my 200 which is standard with all the anti tamper things In place

Click to expand...

a picture of this new mark would be really useful

Oh....
and ideally, mop out all the diesel from the chamber with some kitchen roll, until it's as dry as possible and then have a drive and see if there's any wetness / diesel returned.

exmed wayne said:

a picture of this new mark would be really useful

Click to expand...

I’ll see if I c

exmed wayne said:

Oh....
and ideally, mop out all the diesel from the chamber with some kitchen roll, until it's as dry as possible and then have a drive and see if there's any wetness / diesel returned.

Click to expand...

trying to get a picture at the moment, I did forget to mention that I dried up the diesel before reassembly and it’s doesnt seem to have come back, I did however only drive it for 20 mins

Unfortunatly it’s really hard to get a pic as the line is very faint but the little drawing explains what I’m seeing.
Also cheers for the help guys as I’m not the brightest spark when it comes to the techy bits