diesel rattle in D4D Prado

[Chippy]

.. and I thought I was Robinson Crusoe!

Why's that ... did it only happen on Friday ?? :lol: :lol: :lol:

Sorry Masso .... I must work on my self control, I must work on my self control, I must work on my self control ...... :wink:

Cheers
Chippy

[Steve & Sandra]

this new common rail emission technology has the injectors firing every stroke apparently, sounds like something a miss. Does it sound like the fuel timing is advanced too much. Ive worked on cummins engines that used to rattle until the lube oil was up to temp, it was called step timing i think. Its been years since i was in the trade.

[clifton]

Hi Steve /Sandra,

No they do not inject on every stroke otherwise we would get severe fuel dilution and high bearing surface wear, but I know where you are coming from.

The 1KD-FTV engines are HCCI Engines which stand for Homogeneous Combustion Compression Ignition Engines what a lovely acronym Aye.

The Toyota IKD-FTV engine uses UNIBUS (Uniform bulky combustion) which comprises a combination of early and late injection timing.

The operation is up to half load and speed. The concept is described by
Toyota Engineers and many papers have been written on the subject.

The early injected fuel undergoes a low temperature
reaction while the late injection serves as an ignition trigger and sets off
the high temperature reaction. The first injection or pilot injection quantity is small.

Hope this helps a little

[sacred cow]

I wonder if the unacceptable noise in some D4D engines has something to do with the oil used and/or age of the oil. Those of you with this problem could you please advise the following;

(1) How many kilometres after the oil was changed did the noise first appear?

(2) What is the viscosity of the engine oil?

(3) Is the oil fully mineral, partly synthetic or fully synthetic?

(3) Can you please advise the brand and type of oil?

Thanks
Glenn

[Steve & Sandra]

I was under the impression they also injected on the exhaust cycle to improve the stoichiometric condition, also to reduce NOx and PM.
I have been out of the trade a long long time. So im trying to learn again.

Cheers

Steve

[Steve & Sandra]

for others that may be interested.

UNIBUS ( uniform bulky combustion system )

Technology that enables rapid combustion at low temperatures, by dividing fuel injection into a diesel engine into two stages, first creating a preliminary air-fuel mixture and then delaying the injection timing for the remaining fuel.

Also used to reduce the combustion noise at lower engine loads and speed.

its also related to the exhaust emissions

Cheers

Steve

[ronb1002]

My D4D is doing exactly the same. Started about 1000Kms ago at 31000Kms. Sounds like one cylinder only. Stops after 2 minutes. Loudest at 2000rpm under modest load. Oil change made no difference. Quite scary!

[Dieselman]

I drove a mates Hilux one cold morning and it definately made the same noise under slight throttle at about 2000rpm. This is a work ute and now has 145,000kms under its belt with the noise being the same since new.
Very wierd after getting used to a 1kz when cold.

From what I understand it is just a common rail thing of injecting a very small amount of diesel very early in the cycle to get ignition and then injecting the full fuel load at the correct time. This is all to meet emissions which are now very strictly controlled even with a cold engine (previously emission levels only needed to be met with hot engine).

Ive worked on cummins engines that used to rattle until the lube oil was up to temp, it was called step timing i think. Its been years since i was in the trade.

The old Big Cam 4 is not even in the same universe but even in 1986 they where trying to advance the timing when the engine was cold to cut down on smoke. The rattle is not that much different though


Ben

[clifton]

Hi Steve,
You are correct there is a post injection, the whole reason for the HCCI engine development was to meet Euro NOx and particulate emissions from diesel engines, I didn't elaborate on the techo bits as I didn't want to bore our members with Diesel Theory.

[Walter]

Yep - mine has just started to do this at 17,000km / 6 months old