1991 Mercedes 300D

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SandMAuto - 14 Dec 2006 20:25 GMT

The #4 cylinder is has a low pinging or knocking at idle but the noise
stops when I hit the accelerator. Anybody knows what the problem can
be? Please advise.

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Richard Sexton - 14 Dec 2006 20:56 GMT

>The #4 cylinder is has a low pinging or knocking at idle but the noise
>stops when I hit the accelerator. Anybody knows what the problem can
>be? Please advise.

They're supposed to sound that was. #4 is good the others may need
rebuild injectors. Quiet diesls need work, they're supposed to sound
like a loud bucket of bolts at idle.

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Richard Sexton | Mercedes stuff: http://mbz.org
1970 280SE, 72 280SE | Home pages: http://rs79.vrx.net
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Tom Plunket - 15 Dec 2006 17:43 GMT

> They're supposed to sound that was. #4 is good the others may need
> rebuild injectors. Quiet diesls need work, they're supposed to sound
> like a loud bucket of bolts at idle.

So when my Mercedes guy tells me "your car has the smoothest-running
pre-81 diesel I've ever heard," something's up that this guy doesn't
know?

Here he was asking me about the veggie oil I'm running and what sort of
blends I use...

-tom!

--

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Richard Sexton - 15 Dec 2006 19:02 GMT

>> They're supposed to sound that was. #4 is good the others may need
>> rebuild injectors. Quiet diesls need work, they're supposed to sound
[quoted text clipped - 3 lines]
>pre-81 diesel I've ever heard," something's up that this guy doesn't
>know?

Most people don't.

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Tom Plunket - 20 Dec 2006 00:14 GMT

> > They're supposed to sound that was. #4 is good the others may need
> > rebuild injectors. Quiet diesls need work, they're supposed to sound
[quoted text clipped - 3 lines]
> pre-81 diesel I've ever heard," something's up that this guy doesn't
> know?

(If that sounded snippy, I apologize; didn't mean it like that but I am
truly curious. Alas, without posting sound samples to the group I guess
we'll never know.)

> Here he was asking me about the veggie oil I'm running and what sort of
> blends I use...

...I was just excited about this part. ;)

As of today I'm running about 2/3 virgin soybean oil for fuel. Runs a
treat, although it was a bit tough to get started this morning, and
again this afternoon (although not as bad) after it'd been sitting for a
few hours. I'll probably back off on the mix, but it's pretty cool to
be getting something like 60 miles out of a gallon of petroleum as well
as supporting American farmers with my driving.

I just gotta figure out what's stinking me out inside now; something's
burning on the outside of the engine and making its way into the fresh
air intake.

-tom!

--

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heav - 20 Dec 2006 14:58 GMT

I just read an analyis of running on a mix of diesel and vegetable
(soy) oil. Here is and exerpt:

"Your cold starts will begin to deteriorate, your filter will probably
start plugging, your injectors will get coked up, setting the stage for
ring sticking, glazing of the cylinder walls, increased lube oil
consumption and eventual engine failure -- if you can continue to get
the thing started in the morning. More than 20% or so veg-oil in the
diesel is not a good plan for more than short term 'experiments'."

They say it works great - for a while - but destroys your engine.

Details here:

http://journeytoforever.org/biodiesel_svo.html

> > > They're supposed to sound that was. #4 is good the others may need
> > > rebuild injectors. Quiet diesls need work, they're supposed to sound
[quoted text clipped - 27 lines]
>
> --

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