Classic Mustangs (Tech)Technical discussions about the Mustangs of yester-year.
Welcome to Mustang Forums!
Welcome to Mustang Forums.
You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, at no cost, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!
My Dad had a heart attack and I am now trying to help get his Mustang in order. Some time ago he had someone, he can't remember, change his carb. When I got it, it Idled super hi in park/neutral, and hi in drive, clunking bad when shifted. His tranny leaks bad, seems to be tore up. The car on the road is a beast, I connected the vacuum lines, tuned down the carb as much as possible, but I can't control the idle to a reasonable idle. I have a feeling the carb is to big for the car, help. I use to work on carbuatored cars in HS, so Its be awhile.
I read some where that 1.8 per litre only applies to modified engines. My brother did say that he remembers Dad telling him you can't time it to factory for some reason. He had a stoke as well a Quad by-pass. There really isn't alot of vacuum lines, I did check them, found no leaks, but the timing? I see the 80570 part # on the front. The tranny does not have OD. Is the Trans Linkage hardware required?
Also, If it is idling real high, when you put it in gear it will defiantly clunk. Hopefully that is solved when you fix the idle. Make sure there is oil in the tranny, low levels will cause clunking and much worse issues.
Front manual disc, rear drum
I had a 570 once, the 600 holley was SOOOOOO much better. That being said you should be able to get 'er dialed in with what you've got. +1 for clunking while going into gear because it's idling high. Even if the trans is leaky the front and rear seals and new pan gasket are super cheap so if it shifts ok once you idle it down i wouldn't worry about shelling out for a replacement (especially a piece of **** AOD)
“Some of my finest hours have been spent on my back veranda, smoking hemp and observing as far as my eye can see.” - Thomas Jefferson
Your high idle and clunk into gear is the same symptoms seen when the vacuum line is bad or split at the tail end of the tranny, into the vacuum modulator. That line runs between the vacuum modulator, passenger side of the tranny's tail, up to the rear of the intake manifold. It's a quick check, and simple to correct. I suggest you take a glance before get too deep into your carb.
I checked the vacuum line and it seems fine. The belly tray on the tranny was loose so i gently tightened the bolts. When I disconnected the vacuum line next to the trann vacuum line going into the intake manifold, the idle in park did go down slightly. The idle while in gear is good, its high while in park.
A vacuum leak doesn't necessarily have to come from a vacuum line. The carb may not be sitting tight down against the manifold (or spacer). If the carb is snugged down fairly tight, it may need a gasket between the carb and manifold.
Do you know where the idle adjustment is? are you turning the correct one? Did someone open the secondaries too far at that adjusment? There are many adjusments that could have been made. i would first spary carb fluid around the base to check there for vac leaks.
if this screw has been turned too far it will make the idle high as well
This forum is owned and operated by Internet Brands, Inc., a Delaware
corporation. It is not authorized or endorsed by the Ford Motor Company and is not affiliated with the Ford
Motor Company or its related companies in any way. Ford® is a registered trademark of the Ford Motor