The ´83 Jeep Wagoneer at the Betty Ford Clinic for bad drinking habits

In October my buddy Lothar asked me if I could take a look at his Wagoneer, 360 2bbl with a 727 transmission, as it was a heavy drinker , only got around 6 mpg and was lacking power. At first glance I noticed there were a few vacuum lines disconnected , the TV rod was missing and the exhaust really smelled like it had lots of unburned fuel in it. We agreed that he´d bring the truck over later this year and I´d tinker a bit on it.
The first test drive was maybe 12 miles, it used about a 1/4 of a tank and had trouble to get up to speed, 55 mph was the most it would do. After studying the vacuum diagram and making it work again ( EGR and Air Pump have been deleted ) and making a new TV rod brought quite an improvement, but still the 360 wasn´t peppy at all. The ignition timing seemed to be spot on at 10°BTDC, so that was not the issue. The car performed even worse with the aircleaner on, as the air cleaner housing has 2 vacuum operated air cleaner doors the stay shut if they are not connected to a vacuum source. A few zip ties solved that.
But even with all those improvements fuel consumption and performance were not where they should have been.The plugs were still a bit sooty, and the car eemd to run better with at least vacuum port open, so I decided to look into the carb, a 2 bbl Holley 2150 series. I knew the older Holleys had problems with bad power valves so this could be an issues here aswell , right? But this powervalve looked quite differant from the ones I had seen. It needs an external vacuum source and is originally connected to manifold vacuum. That port in the middle in front of the carb was plugged when I first looked at the car, but once I had the carb dis***embled in front of me it was clear this could not be right. With the power valve connected to manifold vacuum the 360 ran like a champ, no more sooty exhaust gases or plugs. I´m not familiar with AMC V8s, but I felt that a 360 should a least smoke a tire on a wet road, but that was not possible, it just didn´t bite.
But what if the crank dampner was bad and the outer ring had turned a bit so that the timing mark is off a few degrees? I advanced the timing until the engine would fight itself while starting and then backed it off until it would start easy in both hot and cold conditions....this really woke that 360 up, it´s only a one wheel peel but now it will lay rubber until you lift your foot ( or run out of gas, hahaha).
Plugs are perfectly clean now and the engine is running great. It´s still a bit thirsty for my liking ( maybe 13.5 mpg)but that´s with lots of test drives and acceleration ( ) tests. I doubt it can do better than 15 mpg, but that´s to be expected from 4wd truck like that.

The reason I´m sharing this is to make my troubleshooting approach accessible for folks running into similar problems, as I´ve got so much support from you guys and learned so much on here over all those years that I kinda feel obligated to help the next young guy that has a p***ion for his old car but not yet the experience to keep it going.

 

I´d like to add that there are still a couple of things that need to be adressed, but the drinking problem was the most important one. The odometer is acting up sometimes, shocks are all bad , steering and suspension need attention, but it´s Lothar´s car , so he decides when it´s time for those things.

 

Those were never known for being easy on fuel. 15 mpg sounds about right.

Is it full time awd Quadratrac? Or does it have the traditional transfer case with 2wd high. If Quadratrac, there's more losses in drivetrain.

 

Has the converter been removed at some point in its life or is it still hanging around?

 

@38Chevy454 Thanks for your input! Yes, it‘s 2wd in normal operation. If it had permanent awd I doubt that it would have had the guts to spin the tires. It‘s only spinning the right rear.

@oldiron 440 ai‘ve only had this truck here for a week or two, never checked if the converter is the original one. Are they known to go bad?

 

Your symptoms sounded like a bad catalytic converter at first.

 

@SS327 this may be still ahead with all the unburnt fuel and soot it had to digest.
Now that you mention the catalytic converter I wonder if @oldiron 440 was referring to the torque converter in his post, or if he meant the cat? The cat the original one I‘m sure

 

I doubt he meant the torque converter. That would give you a whole other set of problems.

 

Catalytic converter

 

Gut the Cat

Whaaaaaat?

 

Looks like a fiddle bow to me…