Re: Idle / Ignition system

["content22207" <brobertson@xxxx>]

Actually what you're seeing is the ignition at work. Whenever the coil
loses its ground (controlled by ignition module), high tension current
builds up lightning fast, then is discharged to a spark plug as rotor
passes its terminal. If the coil were grounded all the time, no
current would ever build up.

Ignition module and tachometer take their signal from small wire
(blue? I'm at work and can't remember color) that passes from
distributor to compartment behind driver seat.

Take it easy grabbing ignition wires. While coil ground is only 12
volts, HT wires can be as much as 100,000 on newer cars. Even stock
DeLo is 18,000 or so (which I highly recommend bumping up at least to
40,000).

Bill Robertson
#5939

>--- In dmcnews@xxxxxxxxxxxxxxx, doctorDHD@xxxx wrote:
> OK, while playing around with the ignition / idle system of 6530 I
noted 
> something very interesting. As I previous stated, the tachometer
makes small 
> jumps upward, intermittently. I accidentally touched the wire that
goes to the 
> negative side of the ignition coil primary circuit (color WS) and
noted that I 
> was getting intermittent shocks. These shocks were at the same time
that the 
> tach jumped! When I connected a small neon bulb (i.e., an NE-2 for you 
> engineering types), the bulb would blink intermittently along with
the jumping of the 
> tach. (Hey I got fed up with getting jolted so I substituted the bulb 
> instead.) Remember that the engine RPM is NOT jumping only the tach
is. I suppose 
> the tach is getting these voltage spikes and that is why it is
jumping and maybe 
> these spikes are affecting the idle ECU controller. The spike occur
only at 
> low RPM up to about 1400 rpm.
> 
> Does anyone have a clue as to what to do next?
> 
> Dave & 6530 thank you...
> 
> 
> [Non-text portions of this message have been removed]