Date: Sat, 4 Nov 2000 11:06:20 -0800
Reply-To: Antaki <wrack@HOME.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Antaki <wrack@HOME.COM>
Subject: Re: Which cylinder isn't firing??
In-Reply-To: <20001104105139.6559.qmail@nwcst312.netaddress.usa.net>
Content-Type: text/plain; charset="iso-8859-1"
The easy one first - I *always* put anti-sieze on my spark plug threads.
Besides being kinder to the head threads, it makes torqueing them in easier
and more pricise., since I'm not fighting thread friction. I developed this
habit on my old air-cooled VWs, and it has served me well.
**Warning**, do not get the compound on the plug below the threads, since it
will short the plug to ground.
As for troubleshooting the "lazy" cylinder, another method is to remove the
electrical connector to the fuel injector, while the engine is off (don't
want to kill the ECU), one at a time. This will keep unburnt fuel from
nukeing the catalytic convertor.
This might be a good time to invest in a can of spray elecrical contact
cleaner.
Do the listmembers have a favorite here?
R ô¿õ
o
Antaki
- There's a little Quayle in that Bush...
> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@GERRY.VANAGON.COM]On Behalf
> Of d t
> Sent: Saturday, November 04, 2000 2:52 AM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Which cylinder isn't firing??
>
>
> Hello Volks,
>
> Lately, I've started smelling gasoline while driving my 2.1L 1990 GL.
> Alarmed, I immediately checked for any gas spilage or moisture
> under the van
> (looking for the dreaded fuel hoses failures I've heard so much
> about on this
> list) but found no sign of it. I also noticed that the Vanagon is
> not pulling
> as usual (top speed of 75mph instead of the usual 88mph...:-),
> vibrating more
> in idle and taking more time to stabilize in idle after cranking.
> My conclusion: one (or more) of the cylinders is not firing, resulting in
> reduced power, uneven running and unburned gas smell. Occasionaly, I feel
> minute power surges suggesting that the faulting cylinder/s do/es fire
> sometimes.
> I checked the ignition cables but all were fit well. I took them
> off the spark
> plugs and all seemed clean except for one which was a bit oily inside
> (suggesting spark discharges over the oily path instead of normal ignition
> inside the cylinder). I cleaned it with fuel but to no avail.
> So I think one of the plugs is dirty INSIDE (I wonder how it got
> dirty in the
> first place: not tightened properly or the gasket failed?).
> Before I start removing the plugs (I'd prefer to avoid this if possible,
> because I once shreaded the threads on one of my motorbikes
> plugs...:-( ), can
> anyone point me to a debug procedure (in the Bentley or Haynes manuals) to
> find out which cylinder is not firing externally (e.g. if it's an external
> ignition cable or distributor problem).
> I tried to improvise an "ignition voltage sensor" by putting a
> Neon bulb next
> to the spark plug ignition cables (at the end of a large stick of
> course...:-), with no results.
> I know it's probably a dirty spark plug, but this factory
> overhauled motor has
> only 40K on it's clock and it's been serviced regularily, so
> there should be
> no reason for one spark plug getting dirty suddenly (unless it's
> a sudden oil
> seal failure...:-(
> Here's an idea: has anyone found a dirty spark plug just by measuring
> resistance from tip to ground (without removing the plug)?
>
> Last question: does anyone really put the anti-seazure copper
> compound on the
> spark plugs threads before installing them (as recommended in the Haynes
> manual) or is this just for "pharmaceutical" mechanics?...
>
> Cheers,
> T-man
>
> ____________________________________________________________________
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