Disco 1 300 Tdi High EGT and low power

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Rayajos

Rayajos

Member
Posts
23
Location
Spain
Hello folks

I need your help with a problem I've been trying to solve for over one year now. I'll try to explain it in the clearest way I can.

The car has very little power, especially above 2500rpm. EGT climbs very very fast whenever I step on the throttle. The problem is that having no power, and those crazy EGTs, the car is undriveable. Every time I face the slightest slope on the motorway, EGTs can easily get over 600ºC, which force me to lift the pedal and lose speed. And I lose a lot of speed, to the point that trucks overtake me. I never go above 100kmh, so it's not like I'm trying to race the car and expecting it to behave like what it's not.

This problem happened after I did a lot of mods during the quarantine, because that was the best way to not get crazy at that time, so I'll detail the mods:

- 32" tyres, 235/85/R16
- Airtec intercooler (side mounted)
- No EGR
- No cat
- Aftermarket boost pin (from previous owner)
- Suspicious origin turbo with supposedly good internals (I thought the stock one died, it was just a timing issue where it would throw a lot of white smoke....)
- Transfer Defender just fitted
- EGT, Boost pressure and coolant temp gauges

Now I proceed to detail the symptoms:
- EGT easily climbs above 600ºC, in a matter of 400m it can go from 300º to 600º
- Low power, but especially noticeable on the motorway. Can't climb the slightest incline without burning. In small roads it behaves OK

And the tests I've performed:
- Added some more boost pressure, from 1 to 1.2 bar. No difference at all. Pressure is measured at the intake plenum
- Removed the cat. No difference, maybe a bit more power
- New fuel filter. No difference
- Small timing advance, using a 8.8mm drilling bit. No difference
- Boost pin and star wheel turning at the FIP. No difference, I tried with two different pins, but not the OEM one as I don't have it
- THE MOST INTERESTING ONE: today I removed the boost line from turbo to FIP. Power was reduced, but not greatly reduced. Very noticeable on low gears, but I could reach the same speed on the motorway. Max boost was around 0.7 bar. The good thing is that EGT never climbed above 400ºC, and I drove pedal to the metal for several Kms. I can never floor it with the line attached because EGT climb really really fast

The next thing I want to try is getting a new lift pump, but I hope you can give some ideas, I'm starting to really hate the car now...

Thanks for your time, and sorry about my english!
 
No smoke at all! just a black puff when launching, and then nothing. Lots of black some would indicate a lot of fuel, right? so I think at least I would have power at the expense of high EGT, but it's not the case...
Thanks!
 
Rayajos said:
Hello folks

I need your help with a problem I've been trying to solve for over one year now. I'll try to explain it in the clearest way I can.

The car has very little power, especially above 2500rpm. EGT climbs very very fast whenever I step on the throttle. The problem is that having no power, and those crazy EGTs, the car is undriveable. Every time I face the slightest slope on the motorway, EGTs can easily get over 600ºC, which force me to lift the pedal and lose speed. And I lose a lot of speed, to the point that trucks overtake me. I never go above 100kmh, so it's not like I'm trying to race the car and expecting it to behave like what it's not.

This problem happened after I did a lot of mods during the quarantine, because that was the best way to not get crazy at that time, so I'll detail the mods:

- 32" tyres, 235/85/R16
- Airtec intercooler (side mounted)
- No EGR
- No cat
- Aftermarket boost pin (from previous owner)
- Suspicious origin turbo with supposedly good internals (I thought the stock one died, it was just a timing issue where it would throw a lot of white smoke....)
- Transfer Defender just fitted
- EGT, Boost pressure and coolant temp gauges

Now I proceed to detail the symptoms:
- EGT easily climbs above 600ºC, in a matter of 400m it can go from 300º to 600º
- Low power, but especially noticeable on the motorway. Can't climb the slightest incline without burning. In small roads it behaves OK

And the tests I've performed:
- Added some more boost pressure, from 1 to 1.2 bar. No difference at all. Pressure is measured at the intake plenum
- Removed the cat. No difference, maybe a bit more power
- New fuel filter. No difference
- Small timing advance, using a 8.8mm drilling bit. No difference
- Boost pin and star wheel turning at the FIP. No difference, I tried with two different pins, but not the OEM one as I don't have it
- THE MOST INTERESTING ONE: today I removed the boost line from turbo to FIP. Power was reduced, but not greatly reduced. Very noticeable on low gears, but I could reach the same speed on the motorway. Max boost was around 0.7 bar. The good thing is that EGT never climbed above 400ºC, and I drove pedal to the metal for several Kms. I can never floor it with the line attached because EGT climb really really fast

The next thing I want to try is getting a new lift pump, but I hope you can give some ideas, I'm starting to really hate the car now...

Thanks for your time, and sorry about my english!
Click to expand...
Your English is fine! Better than some natives on here!
 
300tdis are brilliant.
If it was me I'd take it back to standard then modify just one thing at a time to see how it goes, what is worth doing and what is not.
It is just too easy to go for loads of mods, some of which fight with others.
Best of luck!:):):)
 
Rayajos said:
No smoke at all! just a black puff when launching, and then nothing. Lots of black some would indicate a lot of fuel, right? so I think at least I would have power at the expense of high EGT, but it's not the case...
Thanks!
Click to expand...

On your boost pin what does the governor pin mark look like? How much of the slope on the boost pin is it using? is the pin mark central on the boost pin flat?
Have you checked the daiphragm to make sur it has not splits?

Cheers
 
neilly said:
On your boost pin what does the governor pin mark look like? How much of the slope on the boost pin is it using? is the pin mark central on the boost pin flat?
Have you checked the daiphragm to make sur it has not splits?

Cheers
Click to expand...

Diaphragm is fine, I just checked. I'm not sure about what you ask about the pin, I'll try to take a picture of it tomorrow. It's not using the complete slope if I remember correctly, but I need to check.
Thanks!
 
Stanleysteamer said:
300tdis are brilliant.
If it was me I'd take it back to standard then modify just one thing at a time to see how it goes, what is worth doing and what is not.
It is just too easy to go for loads of mods, some of which fight with others.
Best of luck!:):):)
Click to expand...

I wish I could, but some original parts are gone...so I'll have to find a solution with what I have. Thanks!
 
Rayajos said:
Diaphragm is fine, I just checked. I'm not sure about what you ask about the pin, I'll try to take a picture of it tomorrow. It's not using the complete slope if I remember correctly, but I need to check.
Thanks!
Click to expand...


Would be useful to see. The std pin is an eccentric cone and can be rotated to adjust fueling. The "boost" pin has a flat surface and the flat is orientated to allow the small internal governor pin to run against it on the centre line of the flat.

It may be the previous owner has played with the adjustments and made it worse.

Seeing how the governor pin runs on the surface will show the stroke and see if it is travelling correctly. It is a good starting point.

Also, is the white nylon ring still in place? if it is how thick is it?

Cheers
 
@Rayajos
For reference,

Here is a picture of a std pin and a "boost" pin , showing the governor pin witness marks.

Cheers
IMG_0580.JPG
 
neilly said:
@Rayajos
For reference,

Here is a picture of a std pin and a "boost" pin , showing the governor pin witness marks.

Cheers View attachment 241554
Click to expand...

Sir, I think you may be pointing in the right direction. I took a picture of the pin, and, as you can see, the mark is quite shorter than yours (which should be worrying especially near the top of the mark, right?). I moved it a little bit so I would get a new mark, and it's the same (grease was removed for the picture). Any idea of how this could be affecting my car and how to solve it? Something tells me this is a minor part of a bigger problem, but I don't know. The nylon ring looks ok

I also took a picture of the star wheel to check the spring preload, it looks to me that the star is too deep inside the thread.

photo_2021-06-30_18-36-28.jpg

photo_2021-06-30_18-36-14.jpg



Thanks!
 
Rayajos said:
Sir, I think you may be pointing in the right direction. I took a picture of the pin, and, as you can see, the mark is quite shorter than yours (which should be worrying especially near the top of the mark, right?). I moved it a little bit so I would get a new mark, and it's the same (grease was removed for the picture). Any idea of how this could be affecting my car and how to solve it? Something tells me this is a minor part of a bigger problem, but I don't know. The nylon ring looks ok
Click to expand...

You definitely are not getting the stroke you should be on that pin.

Has the max fuel screw on the rear of the pump been moved? it should have an anti tamper cover on it.

If I was to hazard a guess, it looks to me like the previous owner has made adjustments , got confused and reduced the max fuel screw to stop black smoke. But you need to look to see if that screw on the rear of the pump has been moved.

Write down where you are starting and count the turns or adjustments you make.
I would wind the starwheel up until diaphragm sits about 4mm above the pump surface before you put the cap on. The threaded black coloured centre of the pump should show about 2 to 3mm above the starwheel.

Inside the fuel pump cap the smoke screw ( torx locked with nut) should be about 3mm proud of where it pokes throught the cap.

Take it for a spin.


Those are the basic measurements my pump is set to. But I do run a higher boost pressure.

If it still has no go, then I would say you are either losing turbo pressure to the pump or your fuel pump is running lean on fuel and needs the max fuel screw wound in a little bit, ( only change by 1/4 turn at most and test).


You do not say whether the 600C is during boost or not or on the flat, FYI, at 70 MPH I see 450C on the flat cruising.

Cheers
 
neilly said:
You definitely are not getting the stroke you should be on that pin.

Has the max fuel screw on the rear of the pump been moved? it should have an anti tamper cover on it.

If I was to hazard a guess, it looks to me like the previous owner has made adjustments , got confused and reduced the max fuel screw to stop black smoke. But you need to look to see if that screw on the rear of the pump has been moved.

Write down where you are starting and count the turns or adjustments you make.
I would wind the starwheel up until diaphragm sits about 4mm above the pump surface before you put the cap on. The threaded black coloured centre of the pump should show about 2 to 3mm above the starwheel.

Inside the fuel pump cap the smoke screw ( torx locked with nut) should be about 3mm proud of where it pokes throught the cap.

Take it for a spin.


Those are the basic measurements my pump is set to. But I do run a higher boost pressure.

If it still has no go, then I would say you are either losing turbo pressure to the pump or your fuel pump is running lean on fuel and needs the max fuel screw wound in a little bit, ( only change by 1/4 turn at most and test).


You do not say whether the 600C is during boost or not or on the flat, FYI, at 70 MPH I see 450C on the flat cruising.

Cheers
Click to expand...

Thank you so much, those measurements look nothing like what I have right now, so I'll check it and let you know.

The problem I see is that I get those temps before going full throttle, because whenever I step on it it rises way too quickly. 60mph flat I see about 0.8 bar and 450C, but when a slope comes.... Not enough power to keep the speed up and high temps all over the place. If the slope is long enough, I may go down to 60kmh or even have to stop and let it cool down, because it loses all the power.

Thanks for your answer
 
Think logically, high egt is because of to much fuel or not enough air, what is a std 300tdi egt readings? I would not have thought 600 was excessive by any stretch, I have seen 1000degc on a mad tuned td5.

I would bin that boost pin and fit a std one.

I have no egt gauge on my 200, and that can run about 1.2/4 bar boost under hard load, std boost pin, max fuel screw tweaked, star wheel std setting, been like this for 10 years now.
 
lynall said:
Think logically, high egt is because of to much fuel or not enough air, what is a std 300tdi egt readings? I would not have thought 600 was excessive by any stretch, I have seen 1000degc on a mad tuned td5.

I would bin that boost pin and fit a std one.

I have no egt gauge on my 200, and that can run about 1.2/4 bar boost under hard load, std boost pin, max fuel screw tweaked, star wheel std setting, been like this for 10 years now.
Click to expand...
General consensus is not going above 650C, but as always those are things you read on forums. Aluminium starts melting around those temps hahahaha.

The thing is, adding extra boost didn't make any difference in EGT or in power, and I have no black smoke under heavy throttle. I don't know, I'm completely lost here...
 
Rayajos said:
General consensus is not going above 650C, but as always those are things you read on forums. Aluminium starts melting around those temps hahahaha.

The thing is, adding extra boost didn't make any difference in EGT or in power, and I have no black smoke under heavy throttle. I don't know, I'm completely lost here...
Click to expand...


To make more boost you need more fuel, the issue comes when you add to much fuel and you start rolling coal as the yanks like to put it.

Tuning diesles WITHOUT making smoke is a real art form.

Dont forget you are running defender sized wheels (32 inch versus 29 inch) with disco transfer box, all this will load the motor up even more.
 
lynall said:
To make more boost you need more fuel, the issue comes when you add to much fuel and you start rolling coal as the yanks like to put it.

Tuning diesles WITHOUT making smoke is a real art form.

Dont forget you are running defender sized wheels (32 inch versus 29 inch) with disco transfer box, all this will load the motor up even more.
Click to expand...

The thing is that I'm not rolling coal, which makes me believe that there's not too much fuel, but I can't explain why EGT climb so fast. Timing maybe?

I fitted a defender transfer box recently, and there's an improvement... But not a permanent solution. Thanks for your answer!
 
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