69 vette not running right help
Thread Starter
Intermediate
Joined: Mar 2013
Posts: 31
Likes: 0
69 vette not running right help
Hi all my vet is in Australia so she has come out of hibernation for our summer. She's a manual 350/350 hrs, been driving her for the last 3 weeks but now something strange is happening. once warmed she idles at 1100rpm but the engine vibrates like she has a radical cam in her. when driving and you put your boot into her she's lacking the performance in a big way.
what I have done so far:
checked dizzy all is tight so it hasn't rotated on me
new plugs
ignition leads tested ok
checked all hoses for vacuum leak
new power valve in Holley
any ideas please help thanks
what I have done so far:
checked dizzy all is tight so it hasn't rotated on me
new plugs
ignition leads tested ok
checked all hoses for vacuum leak
new power valve in Holley
any ideas please help thanks
Race Director
Joined: Sep 2001
Posts: 10,560
Likes: 439
From: Wellington, FL
St. Jude Donor '11 thru '25
Hi all my vet is in Australia so she has come out of hibernation for our summer. She's a manual 350/350 hrs, been driving her for the last 3 weeks but now something strange is happening. once warmed she idles at 1100rpm but the engine vibrates like she has a radical cam in her. when driving and you put your boot into her she's lacking the performance in a big way.
what I have done so far:
checked dizzy all is tight so it hasn't rotated on me
new plugs
ignition leads tested ok
checked all hoses for vacuum leak
new power valve in Holley
any ideas please help thanks
what I have done so far:
checked dizzy all is tight so it hasn't rotated on me
new plugs
ignition leads tested ok
checked all hoses for vacuum leak
new power valve in Holley
any ideas please help thanks
Racer
Joined: Dec 2008
Posts: 297
Likes: 19
From: arlington TX
Hi,
On those older motors, there are only 1 or 2 vacuum connections on the manifold/carb. Disconnect and plug those. Does it run ok? YES - problem is with hoses or the stuff the vacuum runs (wipers, headlights, heater, etc.). NO - intake or carb gaskets or internal problems (lifter, etc). High rpm is usually a vac leak. Might check choke/high idle cam on the carb also. Check intake/carb bolts for tightness.
At least this a place to start.
Good luck.
walt
On those older motors, there are only 1 or 2 vacuum connections on the manifold/carb. Disconnect and plug those. Does it run ok? YES - problem is with hoses or the stuff the vacuum runs (wipers, headlights, heater, etc.). NO - intake or carb gaskets or internal problems (lifter, etc). High rpm is usually a vac leak. Might check choke/high idle cam on the carb also. Check intake/carb bolts for tightness.
At least this a place to start.
Good luck.
walt
Thread Starter
Intermediate
Joined: Mar 2013
Posts: 31
Likes: 0
Thread Starter
Intermediate
Joined: Mar 2013
Posts: 31
Likes: 0
Hi,
On those older motors, there are only 1 or 2 vacuum connections on the manifold/carb. Disconnect and plug those. Does it run ok? YES - problem is with hoses or the stuff the vacuum runs (wipers, headlights, heater, etc.). NO - intake or carb gaskets or internal problems (lifter, etc). High rpm is usually a vac leak. Might check choke/high idle cam on the carb also. Check intake/carb bolts for tightness.
At least this a place to start.
Good luck.
walt
On those older motors, there are only 1 or 2 vacuum connections on the manifold/carb. Disconnect and plug those. Does it run ok? YES - problem is with hoses or the stuff the vacuum runs (wipers, headlights, heater, etc.). NO - intake or carb gaskets or internal problems (lifter, etc). High rpm is usually a vac leak. Might check choke/high idle cam on the carb also. Check intake/carb bolts for tightness.
At least this a place to start.
Good luck.
walt
Race Director
Joined: Sep 2001
Posts: 10,560
Likes: 439
From: Wellington, FL
St. Jude Donor '11 thru '25
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Drifting
Joined: Jul 2004
Posts: 1,695
Likes: 65
From: Kissimmee fl
Finalist 2021 C3 of the Year - Modified
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St. Jude Donor '07
You stated you just got it out of storage. What is the condition of the gas? Did you use a stabilizer when you put it away? Have you burned thru a tank of gas? Have you put fresh gas in it yet? Checked for water in the tank?
Racer
Joined: Dec 2008
Posts: 297
Likes: 19
From: arlington TX
Actually, now that I think about it - did it run any different when those fittings were left open?
Another thought/tip - when it is running bad, put your hand over the top of the carb (to cut off some of the airflow). Did it run differently then?
Ok, I'll leave you alone now.
Good luck.
walt
Melting Slicks
Joined: May 2012
Posts: 2,192
Likes: 343
From: Allenton Wisconsin
Still running points? Check the dwell reading, look inside the cap for carbon tracking. Stock ign wiring? Check OHM reading on the plug wires. The wires will fail due to location [V shields and between motor mount to block]. T
Thread Starter
Intermediate
Joined: Mar 2013
Posts: 31
Likes: 0
The old Pcv valve looked and sounded ok still rattled when shook but I still replaced it and the vaccum line. Unfortunately still running bad.
Thanks for the help.
Thread Starter
Intermediate
Joined: Mar 2013
Posts: 31
Likes: 0
She's on her 3rd tank now fresh fuel. She had less than 1/4 when I first started her, got fresh fuel just under full tank. Took her out for a good run ran well next day toped her up and then next time I started her ran bad.