Timing problems

superchargedGT1

New Member
Apr 5, 2010
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Hey, I'm looking for help. I've just rebuilt my stang 5.0 1991 gt with a v-1 supercharger. The problem I'm having is it is backfiring through the intake and reving up around 3 grand when it pops. It sounds like a lifter but it doesn't pops on every rotation of the motor, only when the motor slows about 750 rpms is when it pops or backfires. I've checked the compression and number 1 has 130 lbs, 2 has 130 lbs, 3 has 127 lbs, 4 has 130 lbs, 5 has 110 lbs, 6 has 130 lbs, 7 has 125 lbs, 8 has 130 lbs. I'm running about 6 lbs of boost. I've got the rotor button is facing number one plugwire at top dead center on compression stroke. Also when it does fire up it floods really bad, but no smoke. Any help would be great.
 
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IMHO # 5 is too low. Check to see if the valve is adjusted right, if so, squirt some motor oil in the cyl. if it raises the compression then something is up with the rings, if no change its valve related.

On the timing, are you using a light? Going strictly off memory which fails me more and more here lately, set the initial timing on about 12 with 6lbs should be safe unless you hear pinging.

Flooding? Are you sure it's just not from the bad idle and trying to run? I'm not too sure about this part, I'm a carb guy. It seems that the pooter is trying to adjust and make up for the timing problem???

I hope you get it worked out.