My '71 GT6 has a Crane XR-700 ignition system. With the engine
running: alternator voltage is 14.2v, voltage into ballast resistor is
13.8v, voltage out of the resistor is 9.2v. Ballast resistor reads 1.7
ohm (catalog rated at 1.35 ohm). My coil (MSD Blaster 2) reads 1.1 ohm
across the terminals. NOTE: both of my multimeters read 0.3 ohm thru
the leads alone so all of the above resistances could be off.
Additional electrical trivia: Blaster 2 coil came with a 0.8 ohm rated
ballast resistor and Crane specs a 1.2 to 1.9 ohm resistor.
What could be causing such a large voltage drop? Speaking to the people
at Cranes tech line, the XR-700 likes to see 10 to 12v at the coil(+)
terminal for their module - essentially 2v drop from charging voltage.
Reason for this post is that my idle is rough/eratic and the car needs a
bit of choke (triple Weber 40DCOEs) until warmed up. Engine fires
IMMEDIATELY (when ballast resistor is bypassed) on cranking but if the
choke is not partially engaged, the engine will die with in a couple of
seconds. Crane's techs tell me that if the module input voltage is too
low the transistor does not know whether to fire or not - which could
cause a rough/erratic idle.
Off in digest mode, awaiting responses. TIA
/// triumphs@autox.team.net mailing list
/// To unsubscribe send a plain text message to majordomo@autox.team.net
/// with nothing in it but
///
/// unsubscribe triumphs
///
|