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Rough idle at standstill
#1
Wrench 
Hey guys! It's been a while since I've posted largely due to me just getting the car back after a 6 month spa(shop) treatment getting some welding and wires re-run for power windows and such.

Since I picked it up, I notice it feels like a rough idle. It sounds choppy for lack of a better word. But when I accelerate, it is still choppy for a few seconds then hums like normal. I have checked the vacuum lines and everything is new and good to go. I'm thinking it is the timing since it hasn't been timed since I've had it. Picked up a timing gun, but I'm not sure how to do it completely. Any suggestions? Also after driving it for 12 miles home, the oil dummy light started flickering lightly then went away. I'm sure that's a contact issue which is no biggie. Thanks in advance for any advice!
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#2
I personally like the rough idle sound hahahaBig Grin With the cam I have in there I have to double peddle it at red lights most of the time.Tongue BUt I'm sure yours is not supposed to do that. Someone will chime in to help you out for sure.

Eric


[Image: a58hgh.jpg]
DRIVE IT DON'T STORE IT!
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#3
If it sat for 6 months it could be the wires have gone bad and/or when they were donig their work they bumped one a little lose.

Put a vacuum gauage on it. Do a search on how to read it. Best diagnosis tool dollar for dollar.

Checking the timing is easy. Disconnect the vacuum line from the distributor and plug it.
Start the car, let it warm up to idle speed.
Shoot the gun at the timing mark. (after connecting it properly, which should be done before you start it)
You will see what the timing is at idle. This assumes the harmonic balance is accurate (usually is but the can slip after a number of years)

I would start it up in a really dark place and look to see if I could see any sparks jumping wires.

'Mike'
73 Convertible - 351C/4V CC heads/4bolt/forged flat tops/comp 270/rhodes/mallory unilite/tri-power/hookers/glasspacks/c6/3.50 limited slip/Gear Vendors/Global West sub frames, strut rods and shelby style traction bars/ Rear sway bar/tilt steering (not original)

Pics of modifications included in:
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#4
72fastback;59016 Wrote:I personally like the rough idle sound hahahaBig Grin With the cam I have in there I have to double peddle it at red lights most of the time.Tongue BUt I'm sure yours is not supposed to do that. Someone will chime in to help you out for sure.

My old engine would idle quiet and smooth. Since I installed the new
Cleveland from Don, with a cam, feels and sounds great Tongue
When you hold the Hurst shifter you can feel the power. Love it.

mike



will e;59023 Wrote:If it sat for 6 months it could be the wires have gone bad and/or when they were donig their work they bumped one a little lose.

Put a vacuum gauage on it. Do a search on how to read it. Best diagnosis tool dollar for dollar.

Checking the timing is easy. Disconnect the vacuum line from the distributor and plug it.
Start the car, let it warm up to idle speed.
Shoot the gun at the timing mark. (after connecting it properly, which should be done before you start it)
You will see what the timing is at idle. This assumes the harmonic balance is accurate (usually is but the can slip after a number of years)

I would start it up in a really dark place and look to see if I could see any sparks jumping wires.

A vacuum gauge is a 'must have' tool and get one you can also pump down. It is sometimes useful to be able to apply a vacuum.
Good idea about starting the engine in a dark place to look for arcing.

mike

[Image: 1_11_11_13_11_50_27.png]
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#5
My guess is the carb has trash/build up in it some where
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#6
Is it the same fuel as was in there 6 months ago???? Get some fresh fuel in there, I stored mine a couple of years ago with 1/2 tank of gas, it ran terrible!

Jeff T.

Low buck, touring style, '73 Convertible "rolling restoration", 351c, 2v heads with a shave and a haircut, Performer intake, Holley 650(ish), roller rockers, screw in studs, guideplates, stainless valves, Duraspark / Motorsports MSD, T-5 conversion. 1-1/8" front, 3/4" rear swaybars KYB shocks and some home brewed subframe connectors. Future plans; JGC steering box, Cobra brakes and... paint, interior, etc.

When I die I want to die like grandpa, peacefully in my sleep... not screaming, like his passenger.

[Image: 1_12_09_14_10_15_11.png]
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#7
Tnfastbk;59076 Wrote:My guess is the carb has trash/build up in it some where

+1
droptop73;59085 Wrote:Is it the same fuel as was in there 6 months ago???? Get some fresh fuel in there, I stored mine a couple of years ago with 1/2 tank of gas, it ran terrible!

+2

73 conv. 460, D0VE large valve heads, Performer RPM manifold, Voodoo 227/233 cam, Holley 950 HP carb, C6 trans, 3.25 trak-loc.
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#8
I vote for trash in the Carb,
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#9
i would first flush the tank and refill with new gasoline.

next could be trash in the carb.

I would check timing just to make sure.

but also i would check your idle rpms. spec is between 650-750 on a stock motor.

if your idle rpms are a bit low it will make a rough idle and turn the oil light on and off flickering it.

would not hurt to just make sure your oil level is correct as well.

I would get new gas first. drain the old gas or try to drive it all out of the tank if possible.
after replacing the gas see if things improve.
if not i would check idle rpms, and timing.

last would be remove the carb and rebuild it/clean it out.

if you have a fuel filter i would replace it or change the cartridge if it is a serviceable one.
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#10
trash in the carb, did it to me when the mustang was sitting in the body shop.

DRIVE IT LIKE YOU STOLE IT*****KEEP YOUR FOOT ON THE PEDAL

Ron

1972 mustang convertible
2005 mustang convertible
1999 mustang convertible white (sold)
1994 mustang convertible white (sold)
2008 ford edge copper
2006 cadillac cts radaint bronze
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