1964 Tbird 390 FE extremely rough idle/no acceleration | Ford Thunderbird forum club group 1955-2005 models

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1964 Tbird 390 FE extremely rough idle/no acceleration

  • Thread starter Thread starter 64TBird64
  • Start date Start date
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64TBird64

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Thunderbird Year
1964
So I finally got the ol girl to come alive, checked fuel delivery and it checks out. brand new fuel pump, clean fuel(91octane)is runnin through it, but when I get it started I need to baby it/pump it to keep it runnin otherwise it’ll sputter out and die. RPMs will not increase with more or less throttle applied, nor is it responsive to starting idle speed adjustment. I’m stumped, any suggestions would be great. Thank you!

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sounds like carb issues. look at primaries while you move the throttle. do you see squirt from the primary venturis? how old is the carb? rebuilding these is really easy. $25 kit from amazon or Mike carbs. go to mikes carb site he has great videos on rebuilding ford autolite 4100 carbs. you can do it. has all info on float settings, choke adjustment, cleaning techniques. a great website for carb fixes. of course make sure you have good spark, no bad wires or plugs. but sounds like carb issues. maybe accelerator pump problems from ethanol fuel.
 
vermbird said:
sounds like carb issues. look at primaries while you move the throttle. do you see squirt from the primary venturis? how old is the carb? rebuilding these is really easy. $25 kit from amazon or Mike carbs. go to mikes carb site he has great videos on rebuilding ford autolite 4100 carbs. you can do it. has all info on float settings, choke adjustment, cleaning techniques. a great website for carb fixes. of course make sure you have good spark, no bad wires or plugs. but sounds like carb issues. maybe accelerator pump problems from ethanol fuel.
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It’s a edelbrock 600cfm, just cleaned and rebuilt. I did rock the throttle just a minute ago and it squirts out the primaries just fine, maybe timing/choke?
 
still sounds like carb problem. who rebuilt it? need to check float settings. maybe vacuum leak. check all hoses to booster, trans' modulator valve, rubber vacuum hoses to firewall and then to heater, a/c, etc. i would take off all hoses that draw vacuum from the intake and then try to isolate which hose might be leaking, but it still sound like carb issues.
 
Tater Salad said:
Vacuum leak? Can you get some help cracking it and listen for hissing or high pitch sounds
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First off, love your username. Good ol tater salad! Cranking it myself I can lean out the window and have an absolute terrible time, which I did and there’s no hissing or whistling coming from anywhere. All new vacuum hoses aswell, and I clamped them to their fittings just for shits n giggles. Can’t be gasket failure/vacuum leak. I think lmao
 
Re: potential vacuum leak, rather than clamping lines to fittings, disconnect them all at the carb and manifold fittings and plug the fittings, then see if the engine will idle. If not, you could still have a manifold gasket leak or carb issue or engine problem.
 
Make sure the vacuum advance has ported vacuum, NOT manifold vacuum.
 
take some carb cleaner and spray it around the base of the carb and intake manifold. If it settles out you found the vacuum leak. Old school trouble shooting. Yup I'm thinking vacuum issues, But tracing them down with these old fords is almost a science as for many years they used vacuum actuators as electro mechanical were still in development.
 
74 Harley said:
Make sure the vacuum advance has ported vacuum, NOT manifold vacuum.
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Actually, I run my '64 TBird's vacuum advance on manifold vacuum and prefer it to ported vacuum. Some adjustment of the advance is necessary but it would not cause the problem that 64Tbird64 is experiencing.
 
How long was it sitting before you woke it up? Was the fuel tank cleaned? I had a car that sat for 6 years and an empty fuel tank. I poured 3 gallons of fuel in and the car fired right up and sounded good. As it idled it started to run worse and worse til it died. would not start without ether. Yup the fuel went bad within 30 min of pouring it in. You however have vacuum issues.
 
Hmm, worth mentioning that in one of these forums a guy said that a 64 TBird gas tank holds 21 gallons however the last 3 gallons are below the pickup in the gas tank.
 
No vacuum leaks, got it running perfectly. Timing was too advanced, previous owner moved disty one notch back, caused it to be about 20° too advanced. Funny enough, it’s running perfectly timed and tuned off of gas I had in a gas can I forgot about, put fresh gas in and it runs just the same. Not a single vacuum leak anywhere, but I appreciate the input y’all!
 
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