steveo

steveo

Well-Known Member
If the thin pipe from the turbo to the Injection pump was split, what symptoms would you expect? Off boost black smoke when accelerator pressed hard? Lack of guts at higher boost and speed?

the pipe itself is quite bendy and long (technical term), so replacement just to try it doesn't seem to be a viable option.

Whats your thoughts, or is anyone keen to split their pipe and report back? :)
 
Is that a yes to splitting your pipe? :) Thought not... finally found the part number, and for 20 quid, its worth a try.
 
it needs replacing or you wont get the extra fuel with the extra air turbo chucks in and so the extra power
 
jamesmartin said:
it needs replacing or you wont get the extra fuel with the extra air turbo chucks in and so the extra power
Click to expand...
That was my thinking - the boost is good, but there's no corresponding power when pushed that bit harder - such as 50mph uphill in 4th/5th - that boost is escaping somewhere!
 
steveo said:
If the thin pipe from the turbo to the Injection pump was split, what symptoms would you expect? Off boost black smoke when accelerator pressed hard? Lack of guts at higher boost and speed?

the pipe itself is quite bendy and long (technical term), so replacement just to try it doesn't seem to be a viable option.

Whats your thoughts, or is anyone keen to split their pipe and report back? :)
Click to expand...
Why not just try it yourself? Disconnect the pipe at the banjo on the injector pump and go for a drive, would give the same results as a big split
 
Then if you did it, and you had even less power you could be fairly confident it is ok. Could always try disconnecting it at turbo T piece and blowing down pipe, if you get airflow you have a leak, if not then to prove its not blocked disconnect at FIP and trying again. This time you should get airflow. At the end of the day it is a single pipe and not that hard to prove a leak or blockage.
 
Kwakerman said:
Then if you did it, and you had even less power you could be fairly confident it is ok. Could always try disconnecting it at turbo T piece and blowing down pipe, if you get airflow you have a leak, if not then to prove its not blocked disconnect at FIP and trying again. This time you should get airflow. At the end of the day it is a single pipe and not that hard to prove a leak or blockage.
Click to expand...
How did I not think of that? What a muppet I am today. I blame alcohol. Thank you :)
 
Turns out, the t-piece clamps were loose just after the boost gauge fittings. Note to self, look for the obvious first! While fiddling, took the time to adjust the injection pump too :)
 
Sorry to revive an old thread, however it seems proportionate.

My 300tdi is sluggish, pump rebuilt injectors rebuilt etc and um just slowly making my way round checking then lines. Boost is fine when it revs but if I try to pull away in second at 20-30kph it has no power whatsoever until the turbo kicks in much higher up the rev range...

Now I was checking the turbo to IP line which is not leaking. However blowing into the pipe at the IP side the air slowly hisses out of the intake side of the turbo. Is this how it should be?

I'm a little lost with it at the moment and having driven another 300 tdi defender recently which felt like a sports car compared to my old trusty disco...
 
Yes normal, blow it the other way and there should be no air leak,
The turbo blows air into that small pipe, which signals the IP to add more fuel as the turbo makes more boost.
 
Does it have a new fuel filter on it?
On my son's 200tdi the fuel filter starts to deteriorate after about 6 months, don't know why. Anyway put a new one on and its OK again.
Has the Defender you drove been tweeked in some way.
 
The pipe people are talking about "tells" the injection pump to dump in more fuel when on boost.

Off boost it does nothing at all. It's all (more or less) at atmospheric.

If you're problem is off bost, than it's not that pipe, irrespective of how stuffed that pipe may or may not be, it's still not that pipe affecting an off bost situation.


In more detail -

Turbo pressure increases.
Pipe from the pressure side links to both the waste gate actuator and the injection pump "flying saucer".
Flying saucer is actually a diaphragm, with a shaped pin connected under it.
Pressure rises, diaphragm bends, pin is lowered (or raised, I can't remember - one or the other)
Pin on the bottom of the diaphragm works against another pin that joins to other stuff etc etc and dumps in more fuel.


So none of that happens when off boost. If the issue is off boost (but not on boost) it's not the pipe.


A similar (but opposing) issue is if the pin that the diaphragm pin works against gets jammed, you get the opposite. Works ok off boost, but on boost there's no extra power, as all the pneumatic stuff works but, if the pin is jammed in to the side of the IP enclosure, it never comes out to add more fuel.


I mention this, not to just rant (even though it's Saturday lunchtime) but to explain how it works.


It sounds like your on boost fueling is working, so the pipe is working etc, but the off boost adjustment is out. Which is an IP setup issue, not a pneumatics issue.
 
lynall said:
Yes normal, blow it the other way and there should be no air leak,
The turbo blows air into that small pipe, which signals the IP to add more fuel as the turbo makes more boost.
Click to expand...
Thanks, I did think as much but at whits end with the lack of power. But makes sense as its fine when it boosts!
Anaconda said:
Does it have a new fuel filter on it?
On my son's 200tdi the fuel filter starts to deteriorate after about 6 months, don't know why. Anyway put a new one on and its OK again.
Has the Defender you drove been tweeked in some way.
Click to expand...
New filters all round, it's been like this since I've had it - about 40,000kms. Defender was bone stock, completely original and never been fettled with!
julianf said:
The pipe people are talking about "tells" the injection pump to dump in more fuel when on boost.

Off boost it does nothing at all. It's all (more or less) at atmospheric.

If you're problem is off bost, than it's not that pipe, irrespective of how stuffed that pipe may or may not be, it's still not that pipe affecting an off bost situation.


In more detail -

Turbo pressure increases.
Pipe from the pressure side links to both the waste gate actuator and the injection pump "flying saucer".
Flying saucer is actually a diaphragm, with a shaped pin connected under it.
Pressure rises, diaphragm bends, pin is lowered (or raised, I can't remember - one or the other)
Pin on the bottom of the diaphragm works against another pin that joins to other stuff etc etc and dumps in more fuel.


So none of that happens when off boost. If the issue is off boost (but not on boost) it's not the pipe.


A similar (but opposing) issue is if the pin that the diaphragm pin works against gets jammed, you get the opposite. Works ok off boost, but on boost there's no extra power, as all the pneumatic stuff works but, if the pin is jammed in to the side of the IP enclosure, it never comes out to add more fuel.


I mention this, not to just rant (even though it's Saturday lunchtime) but to explain how it works.


It sounds like your on boost fueling is working, so the pipe is working etc, but the off boost adjustment is out. Which is an IP setup issue, not a pneumatics issue.
Click to expand...
Thanks, yes on boost works fine IP & injectors were overhauled by a reputable diesel shop, which I hoped would help resolve the issue. I ended up tweaking the fueling slightly on the pin which helped slightly but didn't want to push to much without egt sensor...

Its all off boost issues, theres no exhaust leaks either pre or post turbo & everything else is in ok condition or been replaced. Im considering replacing the turbo cartridge with a billet one which should spool up quicker to see if that helps. Otherwise I'm just going to have to put up with it 🥲
 
StewartB said:
Thanks, I did think as much but at whits end with the lack of power. But makes sense as its fine when it boosts!

New filters all round, it's been like this since I've had it - about 40,000kms. Defender was bone stock, completely original and never been fettled with!

Thanks, yes on boost works fine IP & injectors were overhauled by a reputable diesel shop, which I hoped would help resolve the issue. I ended up tweaking the fueling slightly on the pin which helped slightly but didn't want to push to much without egt sensor...

Its all off boost issues, theres no exhaust leaks either pre or post turbo & everything else is in ok condition or been replaced. Im considering replacing the turbo cartridge with a billet one which should spool up quicker to see if that helps. Otherwise I'm just going to have to put up with it 🥲
Click to expand...
Same size tyres as the defender?
 
StewartB said:
Thanks, I did think as much but at whits end with the lack of power. But makes sense as its fine when it boosts!

New filters all round, it's been like this since I've had it - about 40,000kms. Defender was bone stock, completely original and never been fettled with!

Thanks, yes on boost works fine IP & injectors were overhauled by a reputable diesel shop, which I hoped would help resolve the issue. I ended up tweaking the fueling slightly on the pin which helped slightly but didn't want to push to much without egt sensor...

Its all off boost issues, theres no exhaust leaks either pre or post turbo & everything else is in ok condition or been replaced. Im considering replacing the turbo cartridge with a billet one which should spool up quicker to see if that helps. Otherwise I'm just going to have to put up with it 🥲
Click to expand...


It's going to be fuel pump setup.

The pin on the bottom of the diaphragm is commonly called the "boost pin".

That works against the "fuel metering pin"

The boost pin is kind of vertical, and the fuel metering pin comes in perpendicular to it.



The boost pin is an asymmetric cone shape. So you can adjust fueling by rotating it. At different rotations it will control the fuel metering pin to greater or lesser extents.

But...

I can't remember if the off-boost is affected by the pin rotation. It may be, or may not be - I just can't remember.

It's dead easy to get to have a look. 4 screws on the flying saucer and you're in. The diaphragm and the pin lift out and you can rotate them both.

Take note of the position when you start. Mark the top of the diaphragm with the front of the vehical or something. You will be able to see a "witness mark" on the pin but it's worth marking the diaphragm before you take it out.


So, have a look at the pin. See if rotation will help you.


Also... (and I don't know so much about this) there is a "star wheel" that controls, either (and again I can't remember) the slackness of the diaphragm. The spring pressure on it. Ie how easily it moves. I'm not sure if it controls the "off boost" position though. Have a look on youtube. Most of the vids just say "turn this" or "turn that" without an explanation but you'll probably find something.

It may be, for example, that you need to turn up fueling across the whole range, and then rotate the pin to reduce the fueling on boost. It's a balancing act.

But, whatever, it seems like you have too little fuel off boost. I doubt a new turbo will make any real difference as it's fuel pump setup rather than turbo.
 
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