RE: [doc] Stalling After 5 minutes

[Nick Tomlinson <nickandkathryntomlinson@xxxxxxxxxxx>]

The frequency valve is on the right hand cylinder head near the bulkhead (assuming you are at the back of the car looking at the engine).
 
The other faint buzzing you can hear is probably the idle speed control valve.
Disconnect the black lead to it to isolate it.
 
Good luck.
 
NickT.

James Macpherson <james.macpherson@xxxxxxxxxx> wrote:
Thanks for the info. I will try some more tests but I'm not very
technical!!
But when the car had stalled there was a constant buzzing coming from
the engine bay until I switched 
the ignition off. Is this the frequency value buzz you mentioned?

I tested the spark by removing a spark plug and plugging the HT lead in
resting it on the engine block and
getting someone to turn the engine over and there was no spark. Then
when the spark plug started sparking again a few minutes later the
engine fired up running on 5 cylinders like you'd expect.

James


-----Original Message-----
From: Nick Tomlinson [mailto:nickandkathryntomlinson@xxxxxxxxxxx]
Sent: 18 July 2005 16:16
To: doc-uk@xxxxxxxxxxxxxxx
Subject: Re: [doc] Stalling After 5 minutes


Sounds like its electrical (going on your description)

Start by using an oscilloscope/ dwell meter to see if the coil is being
switched to earth by the ignition amplifier.

If you don't have any of this equipment then you could perform a quick
check for this is.
With the ignition on and in position no. 2 (dash board lights lit),
remove the vacuum pipe from the distributor. Put another pipe on the
vacuum advance and then suck it until you get resistance. This will move
the baseplate round.
When you let go of the pipe and air rushes in the advance will be lost,
the baseplate will move, it will induce/ change the field near the pick
up in the distributor, the signal will be amplified by the ignition
amplifier (fed from fuse #1 from main relay from top of my head) and
will switch the earth side of the coil. This switching of the coil is
also connected to the fuel pump relay that in turn operates the fuel
pump and fuel circuit (computer?) that operated frequency valve near the
cylinder head. If you can hear them buzz for a second then you know this
side of the ignition system works. If you have no spark but this works
then it is likely to be temperature related with the coil. You can
confirm this by taking resistance readings of the coil when it is in a
good state and when you get no spark. (Obviously without the engine
running, ignition key out and all of the coil terminals removed
including the HT lead).

Sounds a bit long winded but its a quick test and saves having to remove
the fiddly coil cover.

How did you check for a spark? Did you remove the main lead out and see
if you got a blue spark? This would only check for main HT. I would use
a clip over timing light and see if you get an even fire from the
flashing light.

Hope this helps,

NickT.

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