Exhaust Gas Temperature gauge

[rambada]

Hi all,

Re Exhaust Gas Temperature gauge please


Who runs one?
Worth worrying about?
Can the Gap diagnostics be used for this?
If not, is there a bluetooth or app based version?


TIA

[Tombie]

Not required.. 3.0L engine runs its own EGT so the ECU has you covered.

I believe you can monitor using GAP tool in instrument mode

[DiscoDB]

Not required.. 3.0L engine runs its own EGT so the ECU has you covered.

I believe you can monitor using GAP tool in instrument mode

And how’s the kit coming along so we can fit to the 2.7?

(Sorry - not a hijack here).

[BradC]

And how’s the kit coming along so we can fit to the 2.7?

(Sorry - not a hijack here).

I have EGT. I wonder if it became a part of the harness with the MY08 upgrade to accommodate the DPF? If so you might be able to just add it in.

[shack]

And how’s the kit coming along so we can fit to the 2.7?

(Sorry - not a hijack here).What kit are you referring too?

Irrespective of that, I'm not sure any 2.7 had the EGT, we have a late 2.7 D4 and I don't think it's got one.

[Tombie]

What kit are you referring too?

Irrespective of that, I'm not sure any 2.7 had the EGT, we have a late 2.7 D4 and I don't think it's got one.

2.7 dont have built in EGT. I havent worried about fitting it (I did on all previous vehicles) as the tune remains well inside parameters.

[BradC]

2.7 dont have built in EGT.

Mine does.

[shack]

Mine does.Import?

[Tombie]

Mine does.

Yours is a grey import IIRC with DPF?

[BradC]

Yours is a grey import IIRC with DPF?

It was a personal import, and it did have DPF, yes. There were a number of changes to the MY08 to accommodate EU4 and DPF (such as setting faults on EGR flow). I wonder if the EGT connector is in the MY08-> harness.
It'd be interesting to see if the GAP list on other cars has the "catalyst temperature sensors" elements listed in the "complete" list. The one I use is the "Pre-catalyst Exhaust Gas Temperature".

[DiscoDB]

What kit are you referring too?

Irrespective of that, I'm not sure any 2.7 had the EGT, we have a late 2.7 D4 and I don't think it's got one.

Tombie was working on a kit to completely remove the EGR piping which would then provide a blanking plate on the drivers side exhaust manifold where an EGT probe could then be fitted.

[DiscoDB]

2.7 dont have built in EGT. I havent worried about fitting it (I did on all previous vehicles) as the tune remains well inside parameters.

Would be easy to add once the EGR piping is all removed. The blanking plates you are making up would make an ideal place to add a probe to the RH exhaust manifold.

Pretty sure this is where Dazza fits the probe on the 2.7 using a modified TD5 EGR blanking plate that can be made to fit.

[Tombie]

Would be easy to add once the EGR piping is all removed. The blanking plates you are making up would make an ideal place to add a probe to the RH exhaust manifold.

Pretty sure this is where Dazza fits the probe on the 2.7 using a modified TD5 EGR blanking plate that can be made to fit.

I have plenty of plates ready if people are looking to do this....

I just havent had time to pull my vehicle apart

[Discodicky]

Hi all,

Re Exhaust Gas Temperature gauge please


Who runs one?
Worth worrying about?
Can the Gap diagnostics be used for this?
If not, is there a bluetooth or app based version?


TIA

I have a Scanguage 2 and regretfully it doesn't give the opportunity to see EGT's on a D4. I'd like to see my EGT for interests sake more than any other reason.

However, if it's any help to you for your peace of mind, generally speaking, the best way of keeping your EGT down is to keep your revs "up", thus not having the situation whereby your foot on the accelerator is through the floor with the engine labouring in too high a gear and masses of unburnt fuel in the combustion chamber with detonation etc. etc.

Not so much an issue in a D3/4 as the ECU helps control such things by changing gear etc.

And pretty much the only occasion you'd likely have a high EGT in a vehicle is say towing under extreme load up hill under the conditions I mentioned, etc.

[scarry]

I'd like to see my EGT for interests sake more than any other reason.


Same here,i have them on an Ultra guage,on the Tojo,just cos i can.
I am more interested in other parameters,and it displays heaps of them.

We dont tow,only time i have ever seen them in the 500's is in soft sand,slogging along,in very high ambients.But as others have said,once it is knocked back a gear,they come down.Same for auto pan fluid temps.
Up the Toowoomba bypass,locked in 5th,loaded,not towing,36 ambient,on the speed limit,they didnt get to 450.

I dont think monitoring them is important unless you do a lot of towing,particularly in high ambients,or the vehicle is tuned.
Or you just want to.[smilebigeye]

[rambada]

So I worked out that I can now use the Gap Diagnostics Live values for viewing these. Next question...


There are 2 banks and several sensors. - Which sensors are better to use please, 1 or 2?
What is an acceptable or unacceptable temperature?

[Discodicky]

So I worked out that I can now use the Gap Diagnostics Live values for viewing these. Next question...


There are 2 banks and several sensors. - Which sensors are better to use please, 1 or 2?
What is an acceptable or unacceptable temperature?



If you were heading towards/or around 800 deg C for a long time it would be a good idea to change down a gear to get the revs up and temp down.
Depends on the composition of pistons/cyl head etc etc but over 1000 deg for a long time would not be nice.

Scarry's quoted temps are very interesting and about what I'd expect in a modern diesel engine in a vehicle.

As an example, if I was towing my 3.0T van up Toowoomba Hill in my 8 speed 3.0 litre D4, I would expect to be in 4th (maybe 3rd, its been some years since I went up in in my 2009 RRS TDV8 with my van, so memory of steepness not so good...) at around 2400 rpm and I'm sure the EGT would be fine.

[scarry]

If you were heading towards/or around 800 deg C for a long time it would be a good idea to change down a gear to get the revs up and temp down.
Depends on the composition of pistons/cyl head etc etc but over 1000 deg for a long time would not be nice.

Scarry's quoted temps are very interesting and about what I'd expect in a modern diesel engine in a vehicle.

As an example, if I was towing my 3.0T van up Toowoomba Hill in my 8 speed 3.0 litre D4, I would expect to be in 4th (maybe 3rd, its been some years since I went up in in my 2009 RRS TDV8 with my van, so memory of steepness not so good...) at around 2400 rpm and I'm sure the EGT would be fine.

Gee i have never seen anything like those temps,but it could also depend on where the EGT sensors are located in the exhaust system.
i will have to find out.
Cruising at 100km/hr,they are usually around mid to high 300's,maybe just touching 400 on a hill,not towing.

I was talking about the newish Toowoomba bypass,it is still pretty steep,but much straighter and longer, with a speed limit of 90Km/hr,from memory.
The old road is still there,but i havent been on it for years.

[rambada]

Ok - ignorance about to show.

Why would the EGT drop if it was dropped down a gear? Wouldn't the increased revs/workload increase the temp? Or does the hot gas get blown out?

If the EGT drops with increased revs, then I assume this needs to be balanced out with coolant and transmission temps? Is this correct?

[PhilipA]

Well usually you will drop speed a bit so have a lower accelerator position, to maintain similar not excessive revs.
regards PhilipA

[BradC]

Why would the EGT drop if it was dropped down a gear? Wouldn't the increased revs/workload increase the temp?

The only increase in workload is the increase in frictional losses due to the higher engine speed, which is minimal when measured against the work required to keep the train moving.
If you look at it from a power perspective, the lower the engine speed the more torque required to make the same amount of power. The only way to make more torque is more fuel and a bigger bang.

I see a coolant and oil temp difference of ~15 degrees C between 6th and 5th gear when towing at 100KPH on the flat. EGT difference is more like 70C and I use less fuel in 5th.
The engine is making the same power, it's just not working as hard on a per-stroke basis to do it.

[Discodicky]

Ok - ignorance about to show.

Why would the EGT drop if it was dropped down a gear? Wouldn't the increased revs/workload increase the temp? Or does the hot gas get blown out?

If the EGT drops with increased revs, then I assume this needs to be balanced out with coolant and transmission temps? Is this correct?

A high EGT is (generally) due to incomplete/substandard/poor/inefficient (call it what you like) combustion occurring, basically with too much fuel going into the combustion chamber ('cos your foot is flat to the floor) and lots of unburnt fuel still in the combustion chamber.

Some call it "over-fuelling", however there are other reasons for this such as faulty fuel pump/injectors, etc.

The 'easiest' way of causing this situation of high EGT in a passenger vehicle (we are not talking earthmoving equipment here) is by having your foot flat to the floor and the engine labouring at lowish rpm.

Essentially, by dropping a gear or two you are raising rpm and in the process causing a more efficient combustion process to happen.

I think pretty much the only time we'd be likely to get a high EGT is by driving our auto in "manual" and in the process not paying attention to which gear we are in, and then by allowing the engine to labour (as above) in too high a gear then you'll see a high EGT. We'd be towing a heavy load (and probably a hot ambient temp) to exacerbate the situation.

In my opinion, a high EGT is not a problem in the modern diesel passenger vehicle because its basically very under stressed, and the ECU's controlling fuel 'mixture' and other things do such a great job in controlling such parameters.

In the case of a D3/4, and other modern cars such as Scarry's LC200, I assume it would decide that the driver is an idiot and the ECU would message the auto to change gears accordingly??

Coolant/auto temps are less likely to be affected by higher rpm than the engine using lower rpm. They depend much more on ambient temp/load/ and duration of the 'pull' up the hill. We are speaking very generally now.

Having said all the above, I just remembered one of my boys just pre COVID was with his family towing his 21ft van with Nissan Navara (about 2014 model I think) on a very hot day heading south into Sydney from Newcastle.

He was driving the auto in "manual".

Climbing one of those steepish hills on that Expressway, without warning the engine management system shut the engine down to idling and he nearly sh.t his pants. He pulled over and long story short after idling for around 20 mins he managed to get going again. Not sure if it was due to high coolant or auto temp or high EGT. The ECU had detected the situation and acted accordingly.

[DiscoDB]

I have plenty of plates ready if people are looking to do this....

I just havent had time to pull my vehicle apart

PM sent. Cheers.

[PerthDisco]

I have plenty of plates ready if people are looking to do this....

I just havent had time to pull my vehicle apart

Looking forward to the complete DIY sheet complete with tools you’ll need to do this job. I’m keen to say goodbye to the EGR coolers.

[Tombie]

Received. I’m off travelling for the weekend. I’ll revert upon return home