OT: Pinking Diesel Engine

[Bob Eager]

Because the detonation is caused not by compression ignition these days, but by the injector timing.

[Bob Eager]

Probably. Certainly pre-dates the early 1990s, when Tubular Bells II was released.

(many tracks on TBII are named after science fiction stories, and one of them is Dark Star)

[Dave Plowman (News)]

Crank position sensor and trigger wheel or whatever on production engines are generally fixed. The ECU, however, can fire the injectors at any point according to its mapping.

[Cursitor Doom]

it used to be how it worked donkey's years ago, though. In a normally- aspirated diesel engine (they don't make 'em any more 'cos they're s**te) the diesel is sucked in along with air and spontaneously combusts when the compression level and cylinder temperature reach a certain point. But I don't think they've been made that way for decades now.

[Dave Plowman (News)]

I'm rather surprised at that. Don't know every engine of course, but sensors are usually rigidly mounted - and designed to a tolerance whereby changing them doesn't involve any re-programming.

A VR type sensor has an input stage on the ECU which looks for the zero crossing point - so the varying voltage output doesn't matter. Hall effect give a constant voltage output regardless of speed.

And the timing is only critical for best running. Most modern engines with a cam position sensor will run in a limp home mode if the crank position one fails.

[Clive George]

They never made them that way. The diesel was always injected into the compressed air near TDC.

Have a read of

Now glow plug engines, the tiny two strokes used for models, are a different game - but they're not diesels.

[Clive George]

It always was injector timing. These days the injectors are controlled electrically, but they were mechanical in the past - the diesel pump was a timed device, sending a pulse of fuel to each injector at the appropriate time.

[Weatherlawyer]

Diesel valves do need de-coking quite regularly. I think it just means a polish with grinding paste, which should have been done at the time but was unlikely to; however its arriving with the new part sounds fishy.

[Clive George]

Regularly as in once every million miles or so, if that? I'll admit mine have only done 200-230K, so haven't had that much time to get coked up yet.

[Mike Tomlinson]

En el artículo , MrCheerful escribió:

*tumbleweed rolls*

You'll have a long wait; he's off his meds again.

[The Natural Philosopher]

every 1/4 million miles or so,. yes.

I think it just

[The Natural Philosopher]

Absolutely. Do you?

[The Natural Philosopher]

HE said 'check the timing' and that implies altering it. I am just asking how he proposes to do either.

[The Natural Philosopher]

That wasn't what I said.

He said 'check the timing'?

My question was 'how' and 'if its wrong how do you propose to change it'

The point being he doesn't understand how a modern diesel works, if he thinks there are easy answers to the above.

[The Natural Philosopher]

Unbeleivable.

Do you people actually READ what other people write, or its it always just what you THOUGHT they wrote.

It the crank sensor - or other sensors - is out, the computer will not have the correct info to compute the correct injection point.

*whoosh*

What determines the injection level and timing, if not the EMUS 'thoughts'?

[The Natural Philosopher]

Where did I say that it couldn't?

[The Natural Philosopher]

Very old diesels work that way. Fuel-air is compressed and goes bang under compression.

But not seen it for about 40 years...;-)

[The Natural Philosopher]

Well *diesel* engines for model aircraft ARE diesels and they DO work that way.

Some old agricultural diesels inject into the inlet manifold

[MrCheerful]

Who mentioned easy??

Do you understand what pinking is? Do you know what are the likely causes? Do you understand the consequences of ignoring pinking?

Modern diesels work in the same way they have for the last 150 or so years. The method of timing and controlling the timing has changed.

Tiny model aircraft diesel engines are not the ones under discussion.

There is no mention of what the actual engine type is. Checking the timing on a diesel may be done merely with a strobe on some engines, or via computer hookup on others. I would not expect any ordinary person to have the equipment to do so. The results will determine what course of action to follow subsequently. Best bet for the OP is to take the vehicle to a diesel specialist.

[Chris Green]

So very old diesel engines had a carburetter of sorts rather than injectors?