First thing was to pull out the central console Lisa built to hold the radios (and cup-holders), then the glove-box, and finally the "doghouse" that covers the engine inside the passenger compartment. You need the cover off to get at most of the engine.
Shortly after pulling things off, Lisa spotted the most immediate problem: the small black short hose in the center of this photo is a vacuum hose that had come off. She rummaged around and found where it connected, then put it back into place. I restarted the van (with the doghouse off, which is very noisy), and confirmed that the H/AC vents would now change direction correctly.
We put the doghouse back on and reset everything. Lisa took this opportunity to fix some other small things. She repaired the hood-release mechanism, which has been very reluctant recently to open, particularly without someone pushing down on it due to a weakened spring. This made opening the hood very difficult if you were by yourself. She also did a bit of work on re-attaching the under-hood insulation, which has worked its way off of its fasteners; the van is 25 years old, so it's not surprising that many original pieces are quite worn.
After we got cleaned up, Lisa got travelswithkuma and we took the van out for a test ride up I-80 east of Fernley. Unfortunately, not far out of town, the Service Engine light came back on. We drove up to the Hot Springs (we had little choice; there is a fifteen-mile stretch of I-80 east of Fernley with no exits) and came back. On the way back into Fernley, we stopped and bought a new oil filler cap, as the old one was nearly falling out. After lunch and some non-auto errands, we went back home to try again.
A bit of online research turned up how to read the error codes on older GM vehicles (pre-1995). We printed out the instructions and Lisa got her electrical kit so she could connect the A and B terminals on the ALDL connector, which was easy to find once you knew what you were looking for. Per the instructions, the Service Engine light began to blink: 1-2...1-2...1-2... [that means "Diagnostic Mode entered"] 3-2...3-2...3-2... [that means "EGR circuit problem"]
So now we knew the problem was with the Exhaust Gas Recirculation valve. Some more online research pointed us at a useful video about how to remove and clean the EGR valve on the Chevrolet Astro and GMC Safari. Lisa watched it and said she could do that. The valve was just behind the distributor, which itself was relatively easy to remove, although of course we had to take the "doghouse" off again. First, however, we drove to Autozone to get Lisa some more rubber gloves (so her hands wouldn't get all torn up working on the vehicle) and a can of Liquid Wrench (recommended for cleaning the EGR valve). We asked if they could get a replacement EGR valve and they said they could have it tomorrow, and even better, if we didn't actually need it (should the cleaning work), we would not have to buy it and they would just send it back.
Getting the valve off and back on is a bit trickier than the video made it out to be, but eventually Lisa did get it off and used an old toothbrush and the Liquid Wrench to scrub it down. One difference between the video and this valve is that in the video, the valve was electrically actuated; this valve is vacuum-actuated. Hm, something of a pattern forming here.
Unfortunately, while Lisa was pulling the valve, the hard plastic vacuum pipe, brittle with age, snapped. Fortunately, this can be replaced with a length of vacuum tubing, so we drove back over to Autozone (this and the previous trip were in the Rolling Stone while the minivan was partially disassembled) for the short (and not at all expensive) tubing.
Putting the hose back on was not too hard, and Lisa did manage to get the EGR valve and distributor reinstalled. An annoyance of this process is that the fasteners on this vehicle are a mix of metric and SAE measurements. Many of the fasteners were 10 and 12 mm, but the two holding the EGR were 3/8 inch. This photo is what the reassembled engine looked like from my point of view sitting in the driver's seat. The EGR valve is the brass-colored round thing partially obscured by spark plug cables trailing from the distributor cap in the center of the photo.
Lisa sat in the passenger seat and had me start it up. It fired up easily. She listened for a while, then had me try the various heater/AC vent direction switches. Some were fine, but in others, you could hear an odd sort of lumping noise coming from the engine, and not just from having the AC on (that could have been put down to the extra load the AC puts on the engine).
Eventually, Lisa had me shut it down and she began to investigate. After a few minutes, she gave a triumphant cry: she'd found another loose vacuum hose, in a much more obscure location. She ended up having to remove the air filter assembly and feel around in the throttle body housing until she found the fitting onto which the rubber nipple of the vacuum hose slid.
She put everything back together again and I once again started the van and ran it through the switches. No more odd sounds caused by vacuum hoses not having the right vacuum connections. I shut it down and we once again put the doghouse, glove compartment, and center console back in place.
We got cleaned up a bit, retrieved travelswithkuma, and headed out US-50A toward Fallon for another test drive. From one of our previous tests, we knew that well before we reached the city limits we should get the Service Engine Light again. This time we drove all the way to Hazen, about ten miles east of Fernley, with no light. We stopped at Hazen for a few minutes and then went back home: no engine light. No rough running. Everything seems to be working properly. All the vacuum hoses appear to be sucking away just the way they are supposed to be doing.
When we got home, we finished securing tools (quite a chore, what with both the metric and SAE toolkits, the electrical gear for the diagnostic sensor, and so forth), and Lisa, who had been up since 2 AM due to some erratic sleep she's been getting lately, called it a day.
We think that what actually must have happened here was that multiple things had gone wrong about the same time, and while Cory was able to find most of them (and getting a new distributor in the van was a good thing anyway), he missed the vacuum leak; furthermore, we speculate that the plastic vacuum pipe that broke in Lisa's hands was already cracked and leaking anyway, but that this wasn't obvious until we did the other work. In any event, Cory's work wasn't a waste; we just needed this work as well, and we managed to do it ourselves.
It is such a relief to have the Astro running properly again. It means that we can drive it to Spokane rather than the comfortable-but-expensive RV. Tomorrow, Lisa will engage our Spokane Plan A and start cleaning out the Astro and packing for our departure on Wednesday afternoon.