300tdi basic tune and high EGT’s what happening?

[TOR]

I’ve had a basic tune in my 300tdi, boost pin rotated and star wheel wound in. I then went away for the weekend and noticed the car floor seatbox was hot. I’ve decided to put an egt on and check what the exhaust temps were. Very shocked to find I could easily get to 730 (backed off at this point) unloaded and cruising up a slight hill near home. Now when I went away I was towing a smallish trailer and the car was more heavily loaded, so i can only assume I was reaching damaging levels. What else can cause such high EGT’s? Car isn’t blowing any black smoke at all and i can’t see any exhaust restrictions?

Where do I go from hear? And how should I check for damage?

[manic]

If not overfuelled, High EGT could be air intake restriction or boost leak. Do you have a boost gauge?

[TOR]

If not overfuelled, High EGT could be air intake restriction or boost leak. Do you have a boost gauge?

I do have a boost gauge, its a digital gauge and seems to be reaching around 19-20 max (takedn from the inlet manifold). It does however fluctuate up and down a bit as the boost is climbing but I always thought this may just be an issue with the gauge.

Regarding the air intake restriction, do just mean a dirty air filter or is there something else I should check?

[BigBlackDog]

That's a lot of boost if it's the standard turbo. Has it been fiddled with? The fuel pump mods won't effect it that much for boost. The compensator on the injection pump basically shovels in more coal when it sees more air. Restrictions, particularilly downstream of turbo compressor, are going to cause less air more temp.
Apart from the super boost I'd say you've just wound up the fuel too far.

[Blknight.aus]

I’ve had a basic tune in my 300tdi, boost pin rotated and star wheel wound in. I then went away for the weekend and noticed the car floor seatbox was hot. I’ve decided to put an egt on and check what the exhaust temps were. Very shocked to find I could easily get to 730 (backed off at this point) unloaded and cruising up a slight hill near home. Now when I went away I was towing a smallish trailer and the car was more heavily loaded, so i can only assume I was reaching damaging levels. What else can cause such high EGT’s? Car isn’t blowing any black smoke at all and i can’t see any exhaust restrictions?

Where do I go from hear? And how should I check for damage?

Call me :)

[Pedro_The_Swift]

^^^^^^ Just do it....[wink11]

[TOR]

Call me :)

Will do!

[incisor]

then let us know :p

[Pedro_The_Swift]

Road Trip? [wink11]

[Blknight.aus]

from the phone call...

sounds like its been overtweaked for the available boost.

[Red90]

No smoke and high EGTs?

[Blknight.aus]

No smoke is not confirmed,

alledgedly max fuel has not been touched, boost is only at stock settings and the egt's taper once the engine is getting up to speed and the boost is winding in then when the boost maxes the EGT's rise again.

I suspect from what was discussed in the phone call that the spring load has been dropped off too far on the boost compensators cam pin and its only overfueling while trying to accelerate under load and the turbo is lagging, the exhaust exits the rear on the vehicle and is not reliably visible without a trail vehicle or back spot mirror.

[AK83]

You won't really see 'exhaust restrictions', unless you have the ability to open up your mufflers and inspect and then close them up.
My front muffler was all carboned up(apparently) .. either way it was orginal, and the new less restrictive muffler I had them fit made a huge difference.
At that time, I had them leave the rear muffler off, but it caused too much droning on a gentle cruise, so I then had them fit a small muffler(also got them to redirect the rear tailpipe at 45° out to the left, instead of straight backwards and down)
Can now see smoke emitting from tail pipe if I turn mirror down and inwards, as I cruise along.

Anyhow, fitting that rear muffler was a mistake(yet to rectify). it added a minimum of 50°C to the EGT for a given piece of road/conditions, and now with many miles on it .. probably worse!
Exhaust can cause higher EGTs.

Inlet restriction: do you have silicon hoses fitted to the turbo side of the inlet system? Do you have a raised intake/snorkel? if yes, is it home made, or a quality brand item ... etc. etc.
Rubber intercooler hoses can delaminate internally .. I think this could be what the guys refer too as intake restriction. As well as snorkel.

I fitted my snorkel myself soon after I did exhaust and a host of other stuff, and then started mucking about with fuelling. I know zero about fuelling, but just followed advice from here, and following the instructions on 300 tdi fuelling that floats around the internet.
It's an instruction set written by Ian Peterson .. google it.
The more you use it and do it, the more it makes sense on what it is you're doing!

Other thing you haven't specified is manual or auto?
Reason is, when going up this slight incline with trailer attached, if a manual, did you just lug it up in top, lower revs(say 2K) and just keep hard on the pedal? Did you drop to 4th, which allows faster revs, a bit of relief on the loud pedal, EGTs will drop.
Doing that is a bit harder(actually, not harder just more annoying) in an auto, due to the larger difference between 4th and 3rd, compared to the manual's difference between 5th and 4th.

[TOR]

Thanks everyone for the replies especially blknight for his help!

The vehicle has silicone hoses and a centre muffler delete. I’ll think I’ll pull out the intercooler and give it a clean for good measure. It does have a safari snorkel fitted. I didn’t have the egt gauge on when I went away and was towing the trailer. I suspect I was probably using the extra power from the tune a little and holding it in a higher gear than I may have previously.

I can’t visibly see smoke but would really need a vehicle behind to confirm this. I’ve only taken the defender for a quick squirt around the block since fitting the egt before i went away for weekend. I’ll drive it a bit this week and get a feel for how the egts behave.

I did have an egt gauge on it some time ago (was removed as blanking plate was leaking). At the time I did notice the egts could get rather hot up a long hill but not critical. The valve clearances were well out and needed a new air filter so was putting it down to that.

Perhaps I need to do a bit of investigating as potentially there is an underlying issue somewhere else? Perhaps I’ll check the exhaust as best I can.

At this stage I’ll see how it behaving then probably wind the star wheel back a little and rotate the cone to what it was, then I’ll get blknight to take a look and work his magic!

Anyone know the stock star wheel setting by the way?

[Blknight.aus]

Anyone know the stock star wheel setting by the way?

Not really a thing, every vehicle is different..

very unscientifically...

once you have the 4 screws off of the compensator and exposed the diaphragm the spring should hold it about 8-10mm clear of the body with the diaphragm flat.

If you have a look at the length of the original stroke mark on the eccentric cone that will show you the travel the eccentric has been moving up and down against the control pin.

[TOR]

Thanks Mate, I’ll turn it down a bit for now then I’ll come for a visit!

[TOR]

Still need to catch up with Dave! I did turn the pin back close to factory and wound the spring out. I fitted a new 2.5” inch exhaust from the dump back with a single straight through muffler. I’ve been driving around a bit and can still hit 700c if I’m not careful, especially with extra weight on board. I’m getting a little black smoke before it hits boost but nothing crazy. I also changed the air filter.

What else can I do? Could the timing be out? I’m maybe thinking that the wastegate might be a little faulty especially with those high boost levels, would the high boost create extra heat and contribute to high egt’s?

[DiscoMick]

I'm no expert, but I have heard it said they actually need some back pressure and a straight thru is not the best choice. Sounds like you need expert advice.

[TOR]

The exhaust is a recent addition and was having the problem before hand. From what I’ve read and the guy at the exhaust shop, back pressures not really an issue on a turbo diesel.

[weeds]

I had a straight through on my dirty old 300tdi and never had issue exhaust wise.

Shell out a few bucks and have it dyno turned, their instruments can be trusted and it will be setup up better than a tune guessing the best spot.

Is your thermocouple/gauge accurate??

[manic]

20psi on the standard turbo is too high IMO, it is likely increasing your intake temperature more than your IC can handle.

Set the wastegate to hold around 16psi under load (18psi peak/spike) and see if that helps reduce EGT.