Author Topic: I6 200 rough idle...  (Read 1767 times)

Offline tvtommy

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I6 200 rough idle...
« on: August 11, 2016, 11:48:52 AM »
Good morning and thanks for reading....

Does anyone know if the is a cure/fix for the rough idle common to the 200 I6 motors?

I've read that multi carb setups can cure this, but I don't want to lose my original setup.

Thoughts?

Tommy
'67 Lime Gold Coupe - Rescued in 2006
'65 Wimbledon White Convertible

Offline jwc66k

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Re: I6 200 rough idle...
« Reply #1 on: August 11, 2016, 07:33:13 PM »
What year? Smog equipment can create problems. So can a bad valve, an old spark plug wire or a carburetor needing a rebuild.
Jim
I promise to be politically correct in all my posts to keep the BBBB from vociferating.

Offline WT8095

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Re: I6 200 rough idle...
« Reply #2 on: August 11, 2016, 11:06:51 PM »
Start by checking for air leaks, especially around the throttle shaft.
Dave Z.

'68 fastback, S-code + C6. Special Paint (Rainbow promotion), DSO 710784. Actual build date 2/7/1968, San Jose.
'69 Cougar convertible, 351W-2V + FMX, Meadowlark Yellow.

Offline tvtommy

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Re: I6 200 rough idle...
« Reply #3 on: August 12, 2016, 12:41:53 AM »
'67

Had a vacuum gauge on her today, shes solid at 20in, and has an occasional dip on the misses shes experiencing.
'67 Lime Gold Coupe - Rescued in 2006
'65 Wimbledon White Convertible

Offline MattDoscher

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Re: I6 200 rough idle...
« Reply #4 on: August 12, 2016, 09:11:31 AM »
20" of vacuum is real good.  The higher your vacuum the better off you are.  I would double check all 6 spark plugs and their gaps, the condition of the points and their gap (assuming you still have points on it), plug wire condition, distributor cap terminal condition.  All straight 6's have a certain amount of shake to them mostly attributed to the long intake log and a 1bbl carburetor having to feed properly atomized fuel all the way to cylinders 1 and 6.  You can play around w/ your idle speed and fuel/air mixture too to smooth it out.

Matt
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Offline 67gtasanjose

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Re: I6 200 rough idle...
« Reply #5 on: August 12, 2016, 01:53:07 PM »
Varying ignition points dwell angle (as seen with an analog dwell meter) could do the same thing. Usual suspect is worn bushings in the distributor (verified by removing cap and pulling around on the rotor)
Richard Urch

1967 (11/2/66, S.J.) GTA Luxury Coupe, 289-4V w/Thermactor Emissions, C-4, Int./Ext. Decor +many options

2005 (04/05) GT Premium Convertible, Windveil Blue, Parchment Top w/Med. Parchment interior,  Roush Body Appointments

Offline tvtommy

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Re: I6 200 rough idle...
« Reply #6 on: August 12, 2016, 08:11:05 PM »
Looks like I have a few things to do this weekend =)
'67 Lime Gold Coupe - Rescued in 2006
'65 Wimbledon White Convertible