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- Sep 25, 2011
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Hi all,
I'm in Australia, but the info should translate as I'm running a GM engine. It's an early 80's cast iron V8 with a CDI ignition and Quadrajet carb. All factory fitted. Comps are 120psi wet. 40 psi at idle. No leaks. Engine is new to me but used. Has been rebuilt at some stage in it's life but specs unknown. Seems to have a bit of a cam. New plugs, leads. Old dizzy, cap, rotor and coil but those parts are only 12 months/10k miles old. No visible exhaust leaks or audible sounds.
The issue is that it idles fine but under load but its down on power. Seems to be making like 10-20% of what it should. Won't even do a hill start. Instead, it backfires regardless of timing, both through the carb and out the exhaust - though mostly out the exhaust.
We have:
Checked and rechecked timing over a dozen times across two dizzies [factory CDI and the MSD unit that came with the engine] and two carbs [my rebuilt Quaddie and the Holley 450/465 Economaster that came with the engine]. This was done from base [#1 at TDC and rotor at #1 lead]. We're 100% sure it's timed correctly.
What could this be?
Thank you.
Daniel
I'm in Australia, but the info should translate as I'm running a GM engine. It's an early 80's cast iron V8 with a CDI ignition and Quadrajet carb. All factory fitted. Comps are 120psi wet. 40 psi at idle. No leaks. Engine is new to me but used. Has been rebuilt at some stage in it's life but specs unknown. Seems to have a bit of a cam. New plugs, leads. Old dizzy, cap, rotor and coil but those parts are only 12 months/10k miles old. No visible exhaust leaks or audible sounds.
The issue is that it idles fine but under load but its down on power. Seems to be making like 10-20% of what it should. Won't even do a hill start. Instead, it backfires regardless of timing, both through the carb and out the exhaust - though mostly out the exhaust.
We have:
Checked and rechecked timing over a dozen times across two dizzies [factory CDI and the MSD unit that came with the engine] and two carbs [my rebuilt Quaddie and the Holley 450/465 Economaster that came with the engine]. This was done from base [#1 at TDC and rotor at #1 lead]. We're 100% sure it's timed correctly.
What could this be?
Thank you.
Daniel