More DPF info

[Scruffy Member Find all posts View Profile Close Scruffy]

Need to remove the DPF and the Adblue - from one of my mates who sells diesel engine parts for trucks & buses where adblue has been in use for years - you'll all want to reinstall EGR valves as adblue makes the EGR problem look like a picnic! it is highly corrosive and rots engine parts (manifolds etc) from the inside out!

He loves Adblue it provides well for his family!

[Lski Member Find all posts View Profile Close Lski]

I have just completed a burn while Techstream was active. What I found is the following

1. The DPF filter temperature matches the normal exhaust output temperature until a burn it initiated by the ECU.
2. Sitting stationary and letting the engine idle via ECU control at 900rpm obtains a max temp of around 585 deg
3. Revving the engine to 2000rpm while stationary brings the DPF temp up to 697 deg.
4. Once the filter reaches 8% full the burn ceases and temperatures drop rapidly so any further revving does nothing to the DPF.
5. Driving while doing a burn gives a far lower temperature of around 525 deg.

Some interesting information there cuda!

[Phs Senior Member Find all posts View Profile Close Phs]

I did notice today that the car was ideling at 900rpm does that mean it was in a burn cycle ?

Is there a way to initiate a burn cycle ?

[cuda Advanced Member Find all posts View Profile Close cuda]

I did notice today that the car was ideling at 900rpm does that mean it was in a burn cycle ?

Is there a way to initiate a burn cycle ?

The 900 rpm can happen if your a/c is running. To confirm just switch off the a/c and if it stays at 900rpm thats a burn taking place. There is only one way I know of to initiate a burn and that is through Techstream.

[Phs Senior Member Find all posts View Profile Close Phs]

Thanks for the info cuda

I'll hook techsteam up when I get a moment and have a look

[geo Junior Member Find all posts View Profile Close geo]

I have just completed a burn while Techstream was active. What I found is the following

1. The DPF filter temperature matches the normal exhaust output temperature until a burn it initiated by the ECU.
2. Sitting stationary and letting the engine idle via ECU control at 900rpm obtains a max temp of around 585 deg
3. Revving the engine to 2000rpm while stationary brings the DPF temp up to 697 deg.
4. Once the filter reaches 8% full the burn ceases and temperatures drop rapidly so any further revving does nothing to the DPF.
5. Driving while doing a burn gives a far lower temperature of around 525 deg.

Based on this info I would suggest a 2000RPM burn would be a good idea every 5 to 10,000km. This would ensure most particulate would be removed from the filter increasing the longevity of the filter. It took approximately 12mins to complete the burn from 100% to 6%. I tried to see if there was a difference in DPF differential pressures and catalyst differential pressures. I started with 100% full at Cat at 0.054 and ended at 0.036, and DPF started 3.05kpa and finished with 2.42kpa.

So cuda, running the motor @ 2000rpm for 10-12 mins won't start a burn cycle? You've got to have access to this Techstream to make it work, is that correct? If so why?

[cuda Advanced Member Find all posts View Profile Close cuda]

So cuda, running the motor @ 2000rpm for 10-12 mins won't start a burn cycle? You've got to have access to this Techstream to make it work, is that correct? If so why?

No not quite correct. The ecu initiates a burn approximately every 250 - 300km. I caught the ECU initiated burn at the start of the cycle as I have been watching it very carefully. What I am saying is if you think a burn has started via your observations it may be pertinent to help the burn by raising the rpm's while stationary to 2000rpm. From my observations it seems as though the burns post this burn are taking less time to complete. This may be due to the filter being less clogged.

Thanks
Doug

[Phs Senior Member Find all posts View Profile Close Phs]

I had a burn take place on my way to the bush
Pulled up at near bright and it was idleing at 900rpm. A/C was off so it must have been a burn.

I would always keep an eye on my 79 series exhaust temps, Around town they would sit about 250-350c on the hwy and freeway they would go up to about 350-500c 35" tyres also saw the temps about 50c higher than running 33s

The biggest thing was how quick and low temps would drop from engine braking, or idleing at speed, going down long hill descents with engine rpms at 2000-3000 they would plummet to 150c
Would be interesting to see what a difference running 2" bigger tyre would make on a Burn
A manual burn function would be great, Lots of hills where I live would see exhaust temps get up fairly high

[cuda Advanced Member Find all posts View Profile Close cuda]

I had another burn yesterday and I experimented with the burn temp with respect to rpm while stationary. What I noticed was I was able to achieve 704 deg running the engine at 1400rpm. 2000rpm made little difference to the temp. If I let the engine idle at 900rpm I was getting 545 deg. So it would seem you only need a small increase to the programmed rpm to have a more intense burn.

[Lski Member Find all posts View Profile Close Lski]

It would be great to have a button on the dash to bump up to 1400rpm for a 'intense DPF burn'.

[Phs Senior Member Find all posts View Profile Close Phs]

Had a burn today, noticed it as I pulled into the driveway. So I ran the RPMS upto 1400 for a few mins, I put my hand 300mm from the exhaust tip and it was extreamly hot with no smoke colour or even smell. Odourless. Even with the Auto 900rpm you could really hear the snorkel working

[Bushbasher Out of control poster! Find all posts View Profile Close Bushbasher]

If I let the engine idle at 900rpm I was getting 545 deg.

Where is your temperature sensor for the EGT? When I had my D4D Prado it would idle below 200 degrees at 750rpm. My EGT probe was in the dump pipe right behind the turbo. I'm talking celsius.

[cuda Advanced Member Find all posts View Profile Close cuda]

Where is your temperature sensor for the EGT? When I had my D4D Prado it would idle below 200 degrees at 750rpm. My EGT probe was in the dump pipe right behind the turbo. I'm talking celsius.

I'm not too sure of its location but yeh when cruising I'm running mid 300's. Pulling the caravan up a steep hill pushes it towards the 500's. The 545 relates to when the DPF is burning particulate in its burn cycle. It dumps extra diesel into the DPF unit which increases the temp high enough to burn the soot down.

Regards
Doug

[Phs Senior Member Find all posts View Profile Close Phs]

At a guess it's factory fitted and in or around the DPF

As cuda said the temp is up due to diesel being injected into the DPF.
My 79 series would idle about 190-200c ( dump pipe )