Re: Idle / Ignition system

["Harold McElraft" <hmcelraft@xxxx>]

This symptom usually indicates that the capacitor for the vacuum 
solenoid is not connected. I don't know why but I have seen many 
cars where this is not connected in the wiring harness. Many cars 
have the capacitor located on the firewall near the solenoid. It 
appears to be connected but when you pull open the harness and 
verify it, the red wire of the capacitor is open and is not tapped 
into the black/blue (BU) wire of the solenoid as it should be - or 
on some cars the capacitor is at the micro switch and has been 
disconnected.

Once the capacitor for the vacuum solenoid is connected properly the 
Tach is as smooth as silk.

Harold McElraft - 3354



--- 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]