1985 gt convertible ruff idle & slow throttle response

[Myfirstgt]

I don’t know if these 85 mustang gt have altitude adjustments or not. This car came from Ohio. I was told the car had a full tune up on it before it was delivered here, but it has a ruff idle and when I hit the go pedal, it hesitates for a second. I didn’t know if it just needed some top end cleaner or parts and adjustments?

 

[Potomus Pete]

How long has it been sitting....I don't know much on the carb, but seems easy enough

 

[limp]

i would check the vacuum lines.. The precomputer " smog " on these cars is full of vacuum lines.... With the age of this car I would assume they are in pretty poor shape if they are still original....

 

[Myfirstgt]

Not really sure how long it sat. I doubt it was very long. Owner passed away and car was sold. Obviously the dudes who did the tune up on it and said it was running great had No idea. I will inspect all the vacuum hoses and see what I can find. I’m pretty sure everything on the car is original. I take some pictures.

 

[Mcmahst]

And put a vacuum gauge on it. I suspect you’ll get a low reading. Vacuum lines would be my number one suspect.

 

[General karthief]

There are 'squirter nozzes' pointing towards the center of the front barrels of the carb, those are for the 'accelerator pump' that should shoot some fuel out when the go peddle is pushed. If no fuel shoots out the accelerator pump is bad or needs adjustment, may need the carb freshened up. Ever work on a fuel atomizer (carb) before?
There are other things that could cause the symtoms you are having

 

[Myfirstgt]

I’ve never worked on these type carbs. I’ve done quite a bit of mechanic work on my trucks and cars over the years. I need to find a vacuum hose diagram for this GT.

 

[Mcmahst]

Try this:

http://www.carbdford.com/tech/enginesketch.jpg

 

[Myfirstgt]

Good lord that’s a lot of vaccum lines. Guess I’ll be busy for awhile. Thank you Mcmahst.

 

[85GTStangGuy]

Is this car an automatic or a manual?

 

[Monkeybutt2000]

Is this car an automatic or a manual?

This is KEY information.

 

[Myfirstgt]

Auto

 

[General karthief]

That may be CFI?
Central Fuel Injection. Looks like a carb with a couple injectors stuck in the top of the throttle body.

 

[Myfirstgt]

You are correct. That’s what this car has.

 

[AeroCoupe]

Can you post a picture of what you have?

 

[limp]

That may be CFI?
Central Fuel Injection. Looks like a carb with a couple injectors stuck in the top of the throttle body.

Good point, I always " ASSUME" they are manuals...

 

[Myfirstgt]

Can you post a picture of what you have?

Absolutely. I’ll take some and post them.

 

[Noobz347]

Anybody have a complete list of what is necessary to swap one of these to a 4bbl carb?

I don't know a ton about the CFI but I do recall the carbed cars stomped all over them.

 

[qikgts]

Anybody have a complete list of what is necessary to swap one of these to a 4bbl carb?

I don't know a ton about the CFI but I do recall the carbed cars stomped all over them.

I don't think I've ever seen a complete list in one spot. Right off the top of my head... Intake manifold, dizzy and ignition swap as it's got TFI, need to regulate down the fuel pressure or swap to a whole carbed style fuel system, I think there may need to be some minor wiring changes made for the WOT AC cut out switch/emissions deal. I can't think of anything else right now.

 

[Noobz347]

That's probably a good start. I can't think of any reason, other than a concourse restoration, to keep the CFI.