Invariably, buying a used, high-mileage late-Seventies vehicle will result in one of life’s biggest headaches: untangling the vacuum and emissions tubing rats nest mess left behind by the previous owners. Straightening out those holiday light strings and nets that you just dumped into a box at the end of last winter is a dream compared to this task, mostly because you can just chuck the old lights and get some new ones next winter for a few bucks. Vacuum hoses you gotta sort out, so I figured I’d work through the mess on my recently purchased Wagoneer sooner rather than later.
I knew from driving around town that something just wasn’t right with the four-barrel 360. Though generally decent and peppy enough to move around so much metal, it stumbled and stalled and overheated enough – especially when hot – to convince me it’s not yet ready for prime time daily driver duty. The previous owner claimed the carburetor had been rebuilt, and indeed it and the fuel filter appear shiny and new, so I decided to focus on the vacuum and emissions hoses.
First, I needed a guide. I’m still searching for a factory service manual with a vacuum diagram, so in the meantime I spent a few hours researching these vacuum systems on IFSJA and other sites. It seems the worst enemy to FSJ owners are the CTO (Coolant Temperature Override) valves, which direct vacuum to and from different sources around the engine depending on engine temperature. But then there’s also the various emissions devices – air pump, EGR valve, etc. – along with the accessories to deal with.
As it turns out, 1977 Wagoneers, for some reason, didn’t come from the factory with the coffee can evap canister, so one headache less there. Also, some previous owner had removed pretty much all of the rest of the emissions devices except the EGR; while he capped the air pump connections off neatly, he left all sorts of hoses uncapped and headed off into obtuse circuits. And then there were all the loose hoses and hard lines not connected to anything that had somehow laid atop the intake manifold without vibrating off.
The CTOs seemed to be in working shape, but it took a couple hours to reconnect them in the proper sequence. Same with the EGR after I discovered that the previous owner had plugged it with a screw. And some hunting and pecking put the rest of the loose hoses in order. Once I figured I had everything in the right place, I went through and replaced the brittle, cracked hoses with new ones. Tech tip: Instead of just yanking the old hoses from their connectors, which often results in the hose end sticking to the connector while the rest of the hose rips free, try twisting the hose first to break its seal with the connector, then pulling it off.
While the 360 runs a little smoother now, it’s still stalling out once it gets hot, so I’m going to check the timing and the carburetor’s idle circuit next. And as you can see from the photo above, I’ve got plenty more to address under the hood of this thing after that.
UPDATE: The eagle-eyed among you may have noticed in the lead photo that something was missing from the carburetor, something I had already removed to get better access to the vacuum lines: the idle control solenoid, pictured above. A little bit of research showed that this part was originally installed to keep the carburetor butterflies open past a certain point with the ignition on, then shut them closed when the ignition was turned off, as an anti-dieseling measure. Without it – or if it’s not working, as is the case here – anytime you take your foot off the throttle, the engine stalls and dies, the exact problem I was having. These appear to be unobtanium now, so I adjusted the carburetor’s idle stop screw to just above the point where the butterflies shut completely. It did diesel a little bit afterward (actually, it dieseled a lot with the idle screw set way too high), but several blasts of carburetor cleaner seemed to take care of that.
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