Need help with vacuum lines

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Just picked up this 83 gran fury at an auction but have a stumbling idle and stalls at red lights a lot but not always, cruises down the road pretty well though.

The circled nipple in the 3rd pic has a vacuum hose connected to it but I can't find out where the other end goes for the life of me and the diagram under the hood isn't much help. Any ideas?

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Camtron

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Appears to be a relocated ESA computer fitting. Has the factory ignition system and lean burn been deleted? Believe that gets capped off if it has been deleted.
Side of factory carb and ESA fitting location.

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I don't think it's been deleted, all the wiring and everything else is still hooked up to the lean burn computer, I tried plugging it off but it makes the car bog down really bad
 

Camtron

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Check around the spark control/lean burn computer box for a nipple without a hose.
 

Camtron

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General diagram reference, over head view from front of engine.

IMG_9228.jpeg
 

Mikes5thAve

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Looks like it's the same one that's plugged in the manual scan. The vacuum advance hooks up at that level but usually at the front. Not needed if you have the computer still.
 

Camtron

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Nah, factory is good at indicating hose sizes and those definitely don’t match.
His BBD has the 1/8” choke diaphragm nipple, the two 1/4” PCV/capped nipples, and an extra 1/8” mystery nipple in the back.
Manual only shows the choke diaphragm and the two 1/4” PCV/capped ports in the back. Fuel in, canister purge, and EGR fitting are all in the same spots. Only difference between them, aside the lack of bowl vent solenoid/idle stop solenoid, looks to be the placement of the ESA fitting.
 

Mikes5thAve

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Its not the right year carb which is why it doesn't match the vacuum diagrams and no esa fitting in the right spot.
It's easy enough to figure out if it has no vacuum at idle its a ported source and not the esa fitting.
 

AMC Diplomat

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What do I do from here brother, I'm 32 years old and have never touched a carb in my life haha
Take the air cleaner off to see what you're working with. Potato pics of the carb with the air cleaner on ain't helping
 

AHBguru

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It's for the air cleaner - heated air nipple is the Mopar name for it.

Runs to the air temp sensor in the air cleaner based, then to the flapper valve in the snorkel. Some vehicles had an vacuum delay valve in this line.

Wrong carb for the car, which should be a feedback BBD.
 

Camtron

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depends really.

Personally, I feel these cars run way better when you delete the spark control and swap in a non feedback carb and standard points ignition.
Other people will tell you if the spark control computer is working right, get a good feedback carb on there and run it factory stock.

Up to you.

What you do know now is, the car was/is having an issue with the carb/fuel system, emission system, or ignition system and someone swapped on the wrong carb and didn’t fix their problem.
 

Mikes5thAve

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Agreed. Mixing and matching parts didn't help. Chances are good there's a problem with the feedback system and someone changed that carb to try to fix things. Who knows maybe they did and it's only time for that carb to be rebuilt.

If that's a ported vacuum source it's NOT for the air cleaner. You'll need to know how that port works and take a look at the engine to see what's disconnected.
 

AHBguru

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depends really.

Personally, I feel these cars run way better when you delete the spark control and swap in a non feedback carb and standard points ignition.
Other people will tell you if the spark control computer is working right, get a good feedback carb on there and run it factory stock.

Up to you.

What you do know now is, the car was/is having an issue with the carb/fuel system, emission system, or ignition system and someone swapped on the wrong carb and didn’t fix their problem.

You can't possibly get a better constant mixture or a better timing curve in the 2bbl cars than with a good running ESA/EFC system. That's a simple fact.

The only exception might be the factory 4bbl cars, as the timing curve is very conservative. But, you can't beat the incredible drivability of a fine -tuned quadrajet, especially on a really cold morning.

Since the port is at the rear of the carb, it's a constant vacuum. Several older vacuum diagrams (pre-1980) show it for the heated AIC system.
 

Mikes5thAve

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Since the port is at the rear of the carb, it's a constant vacuum. Several older vacuum diagrams (pre-1980) show it for the heated AIC system.

Not necessarily. According to this diagram which shows a port in that same spot its not. He needs to check it to see if it has vacuum at idle or not.

 

Camtron

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You can't possibly get a better constant mixture or a better timing curve in the 2bbl cars than with a good running ESA/EFC system. That's a simple fact.

The only exception might be the factory 4bbl cars, as the timing curve is very conservative. But, you can't beat the incredible drivability of a fine -tuned quadrajet, especially on a really cold morning.

Since the port is at the rear of the carb, it's a constant vacuum. Several older vacuum diagrams (pre-1980) show it for the heated AIC system.
while I can appreciate how much you like the factory system, it’s hot garbage and leaves these cars more anemic than they are. Its efficiency can be beaten easily by anyone who knows how to set up and tune a carb and install and wide band AFR gauge and ignition system.
 

Ele115

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Never had AFR gauges and been fine without them. The issue now in 2024 is fuel and parts. It's changed a lot. I like the Quadrajet, but the fuel bowl is way too small for anything other than running errands with low compression smoggers. The TQ was the one that fixed most of those issues. You can get them to work but is it worth it? I can get any of them to work. Do the dance, it's not just one thing, it's timing, temperature, advance, mixture, jets. Get all that just right then one of your parts starts to act up. If you don't have the patience, experience or love these cars, get a Kia. People give up on this stuff and shove them off to the side and walk away. Happens
 

Mikes5thAve

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A properly running computer setup has the best mix of fuel mileage and performance when it's functioning properly but 40 years in with mixed parts that's a different story.
It has pretty strong vacuum at idle

OK so now you need to either follow that vacuum hose to see what it connects to or compare the components under the hood to the vacuum diagram to see what's not connected.
 
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