More ignition help needed! - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Dingfodgy · 08-24-2008, 11:17 PM

Yesterday, many of ya'll chimed in and suggested that my GMC wouldn't fire 'cause the dizzy was 180* out.....you were right! Today I went out to set the timing and for the life of me I cant get this persistent backfire shortly off idle to go away. This leads me to a couple questions.
1. Should the vacuum advance be connected or disconnected to set initial timing?
2. My timing tab has no numbers on it....anybody have an idea what the graduations might be? I guessed that the lines went in 2* intervals, but maybe they're actually 1*....I dunno. (See Pic). Oh yeah, and why do I have two tabs with different markings...which should I use?
Name: Timing Mark.JPG
Views: 183
Size: 33.0 KB

Name: Timing Mark.JPG
Views: 183
Size: 33.0 KB

08-24-2008, 11:17 PM	#1
Dingfodgy Lemme show you something!! Join Date: Apr 2007 Location: St.Helens, OR. Posts: 876	More ignition help needed! Yesterday, many of ya'll chimed in and suggested that my GMC wouldn't fire 'cause the dizzy was 180* out.....you were right! Today I went out to set the timing and for the life of me I cant get this persistent backfire shortly off idle to go away. This leads me to a couple questions. 1. Should the vacuum advance be connected or disconnected to set initial timing? 2. My timing tab has no numbers on it....anybody have an idea what the graduations might be? I guessed that the lines went in 2* intervals, but maybe they're actually 1....I dunno. (See Pic). Oh yeah, and why do I have two tabs with different markings...which should I use? __________________ '67 CST-10 LWB ("Crusty") SOLD* '67 GMC SWB ("Murdock") 2000 K1500 Suburban ("Betty") '95 BMW 325i ("Joy")



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