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1981 superior hearse
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18 Posts
Discussion Starter · #1 ·
Hey! So, I'm having a rather irritating issue with the 81 fleetwood superior. I can drive for a good while, and she performs absolutely flawlessly-but, after a while, I end up with a serious issue. It chokes out as I accelerate-like its not getting gas, but doesn't die(unless I peg the throttle). At first I thought maybe the carb or fuel pump were the issue, but it doesn't happen all the time. Same with a vacuum leak-if that were the problem, I assume it would happen immediately upon ignition, and would affect the idling. It's like it only does it around the top end of 2nd or 3rd gear.... AnyOne familiar with these 8-6-4 motors? Any ideas at all?
Thanks!!
 

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95 FWB 81SDV 96 FWB 94 Fleetwood
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1,672 Posts
Maybe I'm wrong, but my guess is your cat is plugged up... I don't know what state your in, but what I have done is this... Measure the cat body and by a muffler that is the same size... Then take off the cat and cut the bent pipes off and weld them to the muffler so it fits right in and looks like a cat..or you could just have a test pipe made ... but then again maybe I'm wrong and it's not the cat....
 

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1981 superior hearse
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18 Posts
Discussion Starter · #3 ·
I'll definitely look into it. TX only does emissiOns testing in the bigger cities, and it's over 25 years old so it's not required. I might just hack it all off from the cat back... Thanks for the suggestion!
 

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1989 Brougham d'Elegance, 1985 Fleetwood Brougham *Coupe*
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4,256 Posts
Does the V8-6-4 still work?

When it happens, can you smell gasoline?
 

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1981 superior hearse
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18 Posts
Discussion Starter · #5 ·
As far as I know, and judging by gas consumption, I'd say the 8-6-4 has been disabled. Had the mechanic make sure it was disconnected.And there's no gas smell, but a rough idle...
 

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1981 superior hearse
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18 Posts
Discussion Starter · #7 ·
That's the tough part. It started to after about 150 miles of straight highway the first time. The second time, I had ran quite a few errands in the city(put about 45 miles on the odometer). I had shut it off and started it 3 or 4 times.
 

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1989 Brougham d'Elegance, 1985 Fleetwood Brougham *Coupe*
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4,256 Posts
Sounds like a heat-sink problem. When electrical components (such as the fuel injectors, spark plug wires, ignition coil, or distributor) get hot, the resistance increases and the component begins malfunctioning. Cadillac used throttle body injection for 81 (check to make sure yours still has TBI) and if the injectors are old, they could be heat-sinking. Have a reputable garage test the resistance of the injectors when they are hot.
 

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1981 superior hearse
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18 Posts
Discussion Starter · #9 ·
I didn't see injectors when I was going through it-granted, the valve covers on the 8-6-4 are ENORMOUS, but I thought the commercial chassis was carbureted. I'll definitely look into it. I appreciate it.
 

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1989 Brougham d'Elegance, 1985 Fleetwood Brougham *Coupe*
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4,256 Posts
Not all hearses were built on the commercial chassis. If it had the V8-6-4 connected to the 368, then it is (or was) fuel injected.
 

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1981 superior hearse
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18 Posts
Discussion Starter · #12 ·
Ok. Drove it today, and it started acting up after maybe only ten minutes, so the problem's getting worse. Would this still be the heat sink issue?
 

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1989 Brougham d'Elegance, 1985 Fleetwood Brougham *Coupe*
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4,256 Posts
Not if the engine wasn't hot.

If you can, pull out one of the spark plugs and see how cruddy it looks. The car might need a tune up.

You could also try cleaning the throttle body and linkages. They could be binding or sticking.
 

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1981 superior hearse
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18 Posts
Discussion Starter · #14 ·
It was warm, but not up to full temp.(the guy before me installed a water temp gauge). It had been sitting for two years before I got it, so first thing I did was change the oil, plugs, wires, distributor cap and rotor-so I know that's all new. I can use carb cleaner on the throttle body, yeah?
 

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1981 superior hearse
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18 Posts
Discussion Starter · #16 ·
Ok. Thanks. I hate chasing down gremlins- I'm much better at just replacing parts!
 

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'66 SDV, '76 FWB, '80 Hearse, '71 Riviera & '75 Chevy RV
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531 Posts
Can we see a photo of this hearse, and engine? Especially if it's a commercial-glass '81 Superior, I am convinced the motor is a 4bbl 368, not 8-6-4. If it's a standard roofline chances are it's not a Z-code commercial chassis and then could indeed have the V8-6-4. Comm. chassis were carbed 368's up until 1984.
 

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1981 superior hearse
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18 Posts
Discussion Starter · #19 ·
absolutely. Should be able to upload pictures tonight-if not, tomorrow. And again, I appreciate any help I can get-this is my daily, and I can't afford to pay a mechanic to track this down. Plus, most mechanics don't have experience on a car this old-and especially this model. I'm pretty sure it's not a standard roofline, and I swear I saw an intake manifold... I'm hoping it might just be a dirty/bad carb, or any kind of fuel flow issue. But why only when it gets warm?
 
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