Here's that long story short:
I replaced the fuel pump, with the expensive gasket set, got it all back together and... it runs the same. Smooth, stumble. Smooth, stumble. Dang.
A little more:
- When you have to fix something automotive, remember that someone else has fixed the same exact thing before and documented it.
- You could search the internet for the forums and the discussions but, you're better off if you simply...
- Start your search on YouTube. You're going to end up there anyway. Save some time.
- My thanks to George in Texas, whoever you may be, for your humor, sound shade-tree mechanic's methods, excellent use of old comforters, some good classic rock, and some well placed expletives. I owe you a beer.
I spent the weekend sitting cross-legged in my trunk doing the chinese puzzle that is sliding and twising the fuel-pump assembly back into place. I even bought a $20 usb, led-lit, powered camera "boroscope,"** and watched myself slide the male and female bits in the tank into position and then... mate. I felt kinda dirty.
Along the way I built a tool, helping finish the job and separating me from the monkeys. There's nothing like fashioning your own tool. In this case, it was a 1x6 ripped into a 1x2, with two bolts drilled through it to grasp and turn a large lid on the fuel pump assembly.
All put back together, I still couldn't start the damned car or manually prime the pump. It was a very strange experience, largely due to a very strange design. It turns out that the fuel pump assembly gets primed by adding fuel in from the filler cap. Once I dumped in a a couple of gallons of fuel, I was able to get it moving from the pump to the filter in line. From there it was a set of stages; through the filter, and up the line to the engine high-pressure line.
Once I had that going for me, I had a leaking line-in to the filter issue to deal with, but was able to sand the original crush washers which bookend the fuel filter and snug it up.
Varoooooom, quiet, steady idle. I cleaned up shop, put tools away, and took her for a quick test drive.
It is a joy to fix something.
The engine still misses, so the fuel filter and pump was a $400 excursion to nowhere. Except that I'll probably never need to do that again. And if I do, I have the spare, original pump handy.
On our way to church this afternoon, another of our fine vehicles, the steadfast 2000 Chevy Venture, developed a stumble. Very much a misfire. Could it be the original plugs or wires that I've never changed in its fifteen-year life?* Might it be an electronics box?
Best to hook up an OBD2 cable and pull some codes. Or go to Autozone and have them do it. But I'm both cheap and curious, and I have an OBD2 usb cable somewhere around here and the internet's gotta have free software...
Which led to internet searches and a couple of freeware obd2 downloads. Neither could connect to the Chevy's computer, but both hooked right up on the A8. Go figure. One even had real-time readouts of engine RPM, coolant temperature, and vehicle speed. This in the freeware version! The other was the same software I've been saving my old PC for all these years. I guess I can wipe its drive like C3PO and give it away now. I've gained a cubic foot in the basement! It told me that I had an intermittent misfire in cylinder 5.
Sounds like the problem I had back in February, when I had a very non-intermittent misfire in cylinder 4. The fix for that was a $40 Ignition Control Module from Amazon. This time around, they're down to $30.
Another $30 into the A8 won't hurt. Maybe it'll fix it.
Which would give me time to save up for something newer. This is striking my fancy this week:
Because I like weird cars. And this is a beautiful weird car.
I'd better get that Venture fixed, though. I'll probably buy myself a hand-held OBD2 tool on the way home and verify that it is the plugs and wires, and start the process of rotating my engine forward. That car only has to last... oh, a few years more. I just bought new tires for it. And waxed it.
* What? It's a transverse mounted V6. You change 'em! Getting to those rear plugs involves removing engine mounts and rotating (I prefer the term tilting) the engine forward with a ratchet strap. Looking up the procedure (on YouTube. See item 3 above), I had to laugh at the first commentator's quip, "I've come to the conclusion that my mechanic lied when he said he changed all the spark plugs."
** For looking into piston bores and such. The kids laughed when I stuck it in my mouth, nose, ears.