"Keep a Journal: How else are you going to get a good look at who you were?"

Wednesday, December 28, 2005

For Donovan:

As previously discussed; one "bitch" entry about my car...

Actually, I don't have much to complain about...

Currently, the cavalier is running quite well. I have done some checking and I find that we have had the car for 20 months now (we had the DieNasty for 10) and we have had to send it to a shop for repair exactly...zero times.

There are times when the "allotropic" approach to diagnosis and repair of a motor vehicle just doesn't work. Particularily with an older, high mileage vehicle. The Cavalier was running poorly, idling roughly, and the fuel flow was very lean; which led to the engine running a little on the "hot" side.

Do I have to say again how USELESS Haynes Manuals are? Well, I'm going to anyway...

The first edition of any Haynes manual for any new car will be HOPELESS. Years later, after Haynes Publishing gets around to correcting all the poor editing, omissions, and errata of the earlier editions, they will finally publish the definitive home-mechanics manual for that particular car.

By which time, of course, the car is no longer being manufactured...

Haynes is in danger of becoming the #1 publisher of maintenance and repair manuals for OLD cars -- didn't Autobooks used to do that?? Before they went out of business??

Lemme give you some examples from this current automechanical adventure:

I turned first to the "symptoms" pages in the front of the book. I am looking for common causation in the several symptom lists there. They have, for instance, separate lists for "runs poorly", "stalls", "hesitates or loses power". I am looking for a common root problem to all three symptoms. This is the allotropic approach mentioned earlier. It is laziness to assume a complex set of symptoms has a single root cause, but that's modern medicine for ya...

What got me thinking "holistically" about the car's troubles is that there were two symptoms common to each list. Generic, but common:"vacuum leak" and "fuel system problem". Sounds REAL helpful, right? This is where it ocurred to me that there might be more than one problem in there.

So...where to start?

Well, a vacuum leak is the easiest place. Unlike earlier models, this Cav's vacuum devices plug into a common manifold. The manifold, in turn, plugs into a fitting on top of the throttle body. There are exactly THREE devices on the vacuum system that do not plug into the manifold; two of them are to one side of the manifold (one on each side).

The third one is behind the engine...

Owing as how the engine mount broke earlier, and the engine was leaning slightly inboard for a couple of days; I got the notion that anything back behind the engine had probably been subject to undue pressure and might be broken.

The widget behind the engine sits just above the ignition pack...and just below the manifold; it is impossible to see, but my arm is just skinny enough that I could feel my way to it from underneath the car. The end of the vacuum hose (which I couldn't actually see) was loose. I immediately panicked, and ran 'round like the proverbial headless mechanic. I tried to locate the part without knowing the part number and was told that "we don't stock them". This probably meant: "we don't want to be bothered tracking down the widget in question with only a vague description of it's title and function". This meant I had no way to obtain a replacement without having the original in hand to refer to.

SO: I decided to remove the intake manifold...arrg.

On the way, I also noticed the vacuum line for the PCV valve was cracked and leaking. I obtained a new one in the parking lot of Action Auto Wrecking. I WAS going to go in and ask the Guy Behind the Counter if I could go out in the yard and scrounge some hoses (I figured the coolant tank overflow hose was a good match for the PCV hose - plus the tank hose is about 2 feet long; plenty to spare!), when I spotted a piece of hose of the apropriate diameter just in front of where I had parked the car. I don't really like the GBC at Action, anyway...

I've done the manifold before, when I re-did the head gasket and upper-engine seals last year. Scraped my knuckles just as badly this time 'round too. I didn't have to purchase new seals, however; all the extra effort I spent last time dressing the mating surfaces on all the gaskets with permatex paid off. On the throttle body, for example, I was able to re-seal the gasket by re-coating the (still clean!) upper half with permatex black silicone. Both that gasket and the manifold gasket parted cleanly from the mating surface, and I didn't even have to re-dress the manifold. I love that stuff! Best way to ensure a tight engine, especially one with this many miles on it.

Anyway, I eventually reached the "evap vent sol vlv" widget and determined it's vacuum hose was toast. It was pretty late by the time I got there (what can I say? I got up at NOON); so back to the shop I went to scrounge. I found the old air line off Granpa's compressor tank (the one that I replaced after I broke the air nipple on it). The line was robust, and close enough to the proper diameter to make a good replacement. All it took was a little soak in boiling water to loosen 'er up. Did most of the re-assembly after sunset...sigh.

The car idled and ran fine...but.

There was still some hesitation.

I drove it to work the following tuesday. After work, the idle was TERRIBLE...and I couldn't seem to get it to steady out. I spent 10 minutes fiddling with the throttle speed to see if I could get it to a steadier idle at higher RPM. No dice...

Then I had one of those "what do I do now?" moments.

This one was scary: I suddenly got a strong urge to tap that little gold thing on the other side of the engine. I already had my Leatherman in hand, so I rapped sharply on the little vacuum gizmo a few times.

The engine immediately smoothed out.

Hmmm...guess I have to replace that.

But what is it, exactly?

Another look at the symptoms charts when I got home revealed that a rough idle could be caused by a "sticking EGR valve". Would have been REAL nice if Haynes had thought to include a picture of what one looks like. In fact, while I was taking off the manifold, I was trying to move aside a cable bundle that is attached at its far end to the AC compressor. I can reach the connection plug on the AC, but I can't see it. A picture of it in the manual sez; "AC compressor electrical connector (as indicated by arrow in 6.13)"...there's no arrow in the picture, and the picture itself is B +W and so indistinct as to be useless anyway. Typical.

Anyway, on the assumption that the widget was the EGR valve in question, I ventured to Lordco to find a replacement. The EGR valve is on top of the engine, so finding a part number "17090076" was really easy. They had a re-designed aftermarket part, with a kit of adapter "orifices" to fit it to a particular engine. I've now got over 50 differently-sized and individually numbererd metal washers in my hardware box. Funny how they all look very similar, but according to the enclosed chart, "#48" was my number. I got the replacement done all right, and the car is more-or-less back to normal. Now that the idling and power problems are out of the way (I hope), I can spend more time worrying about the way the transmission goes "clunk" when you put the car in gear...

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