You just reminded me of one of
the most glorious days in my short career as a hired wrench... (
introduction)
Back in the summer of '80, a new customer came in with a 'new to him' 5-6 year old Chevy van.
He complained that if he drove around town, everything was fine, but if he tried to pass someone
on a 2-lane highway, the van would suddenly cut out, right at the wrong time. Could we figure
this out and fix it?
The customer left his van behind for us to troubleshoot & repair. Since this sounded like it had the
potential of being a lot more fun than most jobs (ie: replacing a windshield-steaming heater core, etc)
I wrapped up whatever I was currently wrenching on post haste and got right on this opportunity.
A quick look-see at the engine got the manic mechanic juices flowing a bit. Instead of a straight 6 with
a Monojet, the customer had a stock 350 with a Quadrajet. During the test drive it seemed like
the secondaries weren't opening? But since that wasn't the complaint, I probed a bit further. Sure
enough, the customer's concern revealed itself in short order.
You could run 'full throttle' for maybe 8-10 seconds, and then the engine would suddenly starve,
and then nothing. (No doubt the customer experienced some serious pucker factor when that
happened to him during the aforementioned passing maneuver. :0) If you waited a few
seconds, everything would return to normal. The good news was that you could repeat the
problem at will, so at least there wasn't the peek-a-boo intermittent troubleshooting to deal with.
After returning to the shop, my boss & I discussed it for a bit, and we agreed that either the
fuel line got deformed/smashed somewhere, or the fuel pump must be losing it's mojo? The
carb should be rebuilt, and a full tuneup performed. (The engine looked like it hadn't been
touched since it left the showroom floor?)
Since we had the correct carb kit on hand, I went to work on that, and while it sat disassembled
and soaking in the dunk tank, (filled with the old school ominous carb cleaner) I did a full tuneup
on the engine. (cap, rotor, points, condenser, plugs, wires, etc.) Hmmm, the old plugs looked like the
engine was running a bit on the rich side? (insert head-scratching sound.)
Putting the carb back together, all looked well. The original fuel filter in the carb had plugged up,
so of course the fuel pump had pushed the filter off it's seat and against the bypass spring,
which explained why we found quite a bit of sediment on the floor of the fuel bowl?
The fuel line from tank to fuel pump passed a careful visual inspection, but the fuel pump
was pretty janky looking. On a hunch, we checked the engine oil. It was somewhat overfull,
and more importantly, the oil smelled like gasoline?
So of course we suspected that diaphragm inside the fuel pump was bad, so we swapped in a new
mechanical fuel pump, and also performed an oil & filter change.
Putting the carb back on the engine, I ran it on the Sun 1115 engine analyzer in order to adjust
the idle screws, set the timing, and verify that all 8 cylinders were contributing equally to the
task at hand. I went to adjust the idle screws, and observed that the choke had never fully
opened up?
Pretty quick we figured out that the bimetallic choke spring was tired, and the
choke did open some, but never fully. (This explained both the dark plugs and the fact that
the Q-Jet secondaries weren't opening, for the choke linkage locks them out until the choke
is fully off. (ie: the engine is fully up to operating temp.)
Went to the parts store, got a fresh choke spring, mounted it on the intake, and now
with everything sorted out, I finished the tune up, and took the van out for a post-fix
test drive.
With the doghouse off.
And just to be absolutely sure that all was working properly, I also left the air cleaner lid off.
The first on-ramp to the nearby highway told the tale. Not only could I hold WOT as long
as I wanted with no interruption, although the sound of the primaries was mostly hissy,
when the twin 2 1/4" secondary throttle blades opened and the air valves went vertical, the
sound was simply
g l o r i o u s as the engine wound up through the gears.
Goose bumps then. And goose bumps typing this in. Better than most concerts I've attended,
and I like concerts a lot.
And I also finally got to satisfy my curiousity of what it looked like when a Quadrajet
is busy combining a couple hundred horsepower worth of fuel with the air rushing by.
I can still see it. Hope I never unsee it. :0)
And in the interest of ensuring a quality repair, I gave this van a nice, long functional check flight.
Unfortunately, Radio Shack hadn't yet started selling their decibel meters, or I would have
driven home and used that to quantify exactly how loud and proud that 4 barrel barber
shop quartet was all uncorked in the interior of that van.
I returned back to the shop with a big goofy grin on my mug & a thumbs up out the window.
The boss came up, looked in, saw my test setup, and just shook his head. But he was smiling too.
Air cleaner lid reinstalled. Doghouse back on. And on to the next boring job awaiting in the queue.
Epilogue:
The customer paid his bill, hopped in his van, and drove off.
A few days later he swung by and said that the van had been transformed by us.
He had heard about us by word of mouth, and was going to give us all his
business from that point on.
And he did.
****
Thanks for rekindling that memory for yours truly. Years later, while sitting in the
computer lab and waiting for memory diagnostics or a system exerciser to complete, I
would remember that test drive and sincerely wish that the machines in my new gig were
nearly as much fun to test drive.
True story.
@L31MaxExpress, I have no doubt you have subjected yourself to the same
thing...in the pursuit of knowledge. :0)
Cheers --
