dynamite sounding explosions coming from exhaust
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dynamite sounding explosions coming from exhaust
Here lately when I go to crank up the Nova it has been getting harder and harder to start (giving it more gas and more cranking tries than usual) but when it did fire up it would take the normal "warming up" to get a good lopey idle. But the last couple of times trying to start it the idle sounds terrible like it barely wants to idle. Keep in mind I haven't adjusted anything since I've had the car now for a few months and when I got it it ran fine. Well today again it took a longer than normal amount of time to crank it and when it did run (barely idleing) I would get these loud as almost dynamite explosions occasionally out of the exhaust. So loud it hurts your ears and then I just turn it off. I'm just getting into this and have no idea how to tune a carb so yea I plead dumb on my part. But what exactly is happening here? Here's the specs on the motor:
• 383ci sb
• 4 Bolt Main
• Forged Alum Flat Top Pistons
• Forged 5.7 Rods
• Lunati Hydraulic Cam 246 Duration / 520 Lift
• Camel Hump Heads
• Comp Cams Valve Locks, retainers, springs, etc.
• Stainless steel valves
• Victor Jr. Intake Manifold w/ Air Gap
• Holley 750 Double Pumper Carburator w/ 2" Spacer
• Double Roller Timing Chain
• Mallory fuel filter canister type w/ replaceable filter
• Jegs Pro Starter 4.41:1 gear reduction 1.9HP w/ Push Button Start
• MSD Pro Billet Distributor
• MSD 6AL Ignition
• MSD Blaster 3 Coil
• MSD Adjustable Timing Control
• MSD 8.5mm Super Conductor Plug Wires
• Hedman Headers 1 3/4" Primaries to 2 1/2" Pipes w/ Flowmaster Mufflers
• 383ci sb
• 4 Bolt Main
• Forged Alum Flat Top Pistons
• Forged 5.7 Rods
• Lunati Hydraulic Cam 246 Duration / 520 Lift
• Camel Hump Heads
• Comp Cams Valve Locks, retainers, springs, etc.
• Stainless steel valves
• Victor Jr. Intake Manifold w/ Air Gap
• Holley 750 Double Pumper Carburator w/ 2" Spacer
• Double Roller Timing Chain
• Mallory fuel filter canister type w/ replaceable filter
• Jegs Pro Starter 4.41:1 gear reduction 1.9HP w/ Push Button Start
• MSD Pro Billet Distributor
• MSD 6AL Ignition
• MSD Blaster 3 Coil
• MSD Adjustable Timing Control
• MSD 8.5mm Super Conductor Plug Wires
• Hedman Headers 1 3/4" Primaries to 2 1/2" Pipes w/ Flowmaster Mufflers
#3
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Originally Posted by Strokinit383
It sounds like your timing is off. Is your distributor hold down loose?
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Originally Posted by Strokinit383
Sounds to me like its firing too late. Try advancing the timing a little.
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Im not quite sure how those timing ***** work. I would try it there 1st since it so easy to do. Maybe write a small mark on your distributor base and intake manifold as a reference to where you started. That way when you try advancing it if it doesnt work youll know where to go back to.
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Originally Posted by chevydad
bad plug or wire?
#9
I'd check to make sure your wires are arcing for any reason. I'd pull the distributor and get your timing in the general vicinity by finding top dead center, then installing your distributor per directions I'm sure you can find somewhere on the net. You could always check your timing with a light, but that can go bust if you have a different style balancer then was marked for your engine.
I'd for sure pull the adjustable timing **** though, sounds like more trouble then it's worth.
Definitely a timing problem though, cause mine did the same thing when I installed a new distributor. Turns out it's got a new balancer on it, with the wrong timing marks.
I'd for sure pull the adjustable timing **** though, sounds like more trouble then it's worth.
Definitely a timing problem though, cause mine did the same thing when I installed a new distributor. Turns out it's got a new balancer on it, with the wrong timing marks.
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Originally Posted by CarelessAndImprudent
I'd check to make sure your wires are arcing for any reason. I'd pull the distributor and get your timing in the general vicinity by finding top dead center, then installing your distributor per directions I'm sure you can find somewhere on the net. You could always check your timing with a light, but that can go bust if you have a different style balancer then was marked for your engine.
I'd for sure pull the adjustable timing **** though, sounds like more trouble then it's worth.
Definitely a timing problem though, cause mine did the same thing when I installed a new distributor. Turns out it's got a new balancer on it, with the wrong timing marks.
I'd for sure pull the adjustable timing **** though, sounds like more trouble then it's worth.
Definitely a timing problem though, cause mine did the same thing when I installed a new distributor. Turns out it's got a new balancer on it, with the wrong timing marks.
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Originally Posted by Strokinit383
Sounds to me like its firing too late. Try advancing the timing a little.
Originally Posted by CarelessAndImprudent
Definitely a timing problem though, cause mine did the same thing when I installed a new distributor. Turns out it's got a new balancer on it, with the wrong timing marks.
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Originally Posted by Strokinit383
Glad to hear its back running correctly.
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If its shooting gas and air up out of the carb, it now has a little too much advance. Try retarding it by spinning the distributor about 1/4" or less counter clockwise. See if that fixes it.
#15
Sounds like you may want to go ahead and redo the timing completely to see if that fixes all your problems. Put it at top dead center and set your distributor per its directions and then start it and put a light on it.
The 750 dp does sound a bit big, but it shouldn't be causing your problems
The 750 dp does sound a bit big, but it shouldn't be causing your problems
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Originally Posted by Strokinit383
If its shooting gas and air up out of the carb, it now has a little too much advance. Try retarding it by spinning the distributor about 1/4" or less counter clockwise. See if that fixes it.
Originally Posted by CarelessAndImprudent
The 750 dp does sound a bit big, but it shouldn't be causing your problems
Originally Posted by CharlieCobra03
Take it to yer local dyno and do a run with a sniffer in. Get the timing right, get the A/F right and find out what it's putting down all in one trip.
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Originally Posted by Strokinit383
If its shooting gas and air up out of the carb, it now has a little too much advance. Try retarding it by spinning the distributor about 1/4" or less counter clockwise. See if that fixes it.