Possible Misfire Condition New Cam
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Junior Member
Joined: May 2012
Posts: 86
Likes: 10
From: North Florida
Car: 86 Berlinetta
Transmission: 700r4
Possible Misfire Condition New Cam
I swapped in summit cam #8800 and need some help diagnosing a rough idle. To me, it sounds like a potential misfire, but I have no idea where to start. The engine will idle smooth for a few seconds and then "hiccup". I don't want to run the engine too much in case it's a valve adjustment issue.
The car has the original E4ME carb with modifications based on Cliff Ruggles' book. Changes I've made: .036 idle tubes, .0465 down channel restrictions, mixture screw holes drilled out to .076, .082 idle bypass air.
Timing set to 10 degrees BTDC, mixture screws are 3.5 turns out.
I plan on pulling the plugs/checking the wire order, any other suggestions?
The car has the original E4ME carb with modifications based on Cliff Ruggles' book. Changes I've made: .036 idle tubes, .0465 down channel restrictions, mixture screw holes drilled out to .076, .082 idle bypass air.
Timing set to 10 degrees BTDC, mixture screws are 3.5 turns out.
I plan on pulling the plugs/checking the wire order, any other suggestions?
Thread Starter
Junior Member
Joined: May 2012
Posts: 86
Likes: 10
From: North Florida
Car: 86 Berlinetta
Transmission: 700r4
Re: Possible Misfire Condition New Cam
I solved the issue. My TDC mark was off, and as a result, the distributor was pointing at #2 at TDC...
Joined: Oct 2020
Posts: 1,462
Likes: 713
From: Franklin, KY near Beech Bend Raceway, Corvette Plant and Museum.
Car: 1992 Pontiac Firebird
Engine: 5.0L L03 TBI
Transmission: 700R4
Axle/Gears: 2.73
Re: Possible Misfire Condition New Cam
Did the outer ring on the harmonic balancer slip on the hub because the rubber bonding them went bad and that threw off your TDC mark or was it something else?
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