The fastest way to learn a lot about a person, or a vehicle, in a very short period of time is to take a long road trip with them. We'll skip past the human frailties one often discovers about their fellow man and move right along to talking about all of the things one will never really know about their truck until they get out on the road and let it roll. The testbed for a lot of my firsthand knowledge has been the '79 Chevy C10 Big 10 I drove on Rod & Custom magazine's farewell tour to its Americruise event.
It's no secret the two biggest technological contributions to fullsized trucks generally doubling their gas mileage and life expectancy has been the advent of overdrive automatic transmissions and electronic fuel injection. In the case of my '79 C10, or the Americruise truck as it has come to be known, I took care of the gearing situation by installing a Gearstar Performance 4L60E, but the stock Rochester four-barrel carburetor was left in place. There's nothing wrong with a good old-fashioned carburetor; they've served the automobile industry well for over 100 years now. Well, nothing except they cause a lot of sputtering and coughing until the engine warms up and the raw gasoline that pours down the cylinder walls dilutes the engine oil and impairs its ability to lubricate the engine. Couple this with the raw gas going out the exhaust without being burnt not only causes premature engine wear but beats the dickens out of getting good gas mileage.
The first step to any mechanical...
The first step to any mechanical procedure that involves 12-volt electricity is to disconnect the battery.
The last straw for me putting up with a carbureted engine on a long road trip was when I rolled into Denver after spending the day driving in from Lincoln, Nebraska. My truck setup to run at 20 feet above sea level was having a real hard time running in the 5,281 feet of thin Colorado air. In the old days the guys running flathead V-8 Fords dealt with the problem by upping the compression with high-compression heads affectionately known as Denver heads. This took care of part of the problem. When subjected to higher altitudes all engines need to add one degree of advance to the timing for every 1,000 feet of altitude and the carburetor has to be re-jetted to lean it out to run at the right air/fuel ratio. I wasn't enjoying my stay in Denver enough to get out and manually re-time and re-jet my Chevy's 350, but I promised myself I wouldn't drive any truck at a high altitude again until I had fixed the problem. The '79's overall gas mileage wasn't awful on Americruise, but suffered anytime I had run the engine constantly below 2,000 rpm-which was a lot when I had to run in the pack with some of the old duffers at below the posted speed limit.
The engineers at General Motors found the cure for all of the above mentioned problems by introducing electronic fuel injection, or TBI, at the tag end of the square-bodied C10's 15-year production run. For the average guy like me to retrofit a TBI setup to an earlier truck is an over-complicated nightmare. But thanks to the folks at Howell Engine Developments in Marine City, Michigan, there is a computer-controlled fuel injection kit that takes a lot of the guesswork out of the equation. I wasn't able to install Howell's TBI fuel injection system on the '79 because it isn't CARB approved for use in California. I did the next best thing and installed one on my almost identical '75 Chevy Big 10 C10, which is under the cutoff year for California's smog check program. Isn't it a bit ironic, a government bureaucracy impedes folks from "greening up" their truck's carbon footprint?
Installation of TBI requires...
Installation of TBI requires the addition of a fuel return line to the gas tank. The easiest way to handle this was by obtaining a brand-new '87 C10 TBI sending unit from Brothers in Corona, CA, where the part was in stock-that day, no waiting!
Make sure the tank is empty...
Make sure the tank is empty before removing the side-mounted fuel tank. Unbolt the eight bolts from the tank's mounting brackets on the framerail and lower it to the ground. Plugs were used to keep dirt from entering the tank.
The original sending unit...
The original sending unit was removed by knocking the three prangs on the retainer ring counterclockwise with a hammer and flat-tipped punch.
To install the brand-new Brothers...
To install the brand-new Brothers TBI sending unit, the process was reversed (clockwise to install the ring), and the fuel supply line, charcoal canister, and 5/16-inch return line were fitted before reinstalling the gas tank.
To avoid a mix-up of the fuel...
To avoid a mix-up of the fuel lines, the return line was labeled before installing the tank. Another good tip is to make sure all eight bolts thread easily into the tank mounts before installing the gas tank into place.
The electric fuel pump included...
The electric fuel pump included in the kit must be mounted at or below the gas tank's centerline. Note the sending unit wires were routed before re-installing the gas tank.
It is mandatory the large-capacity...
It is mandatory the large-capacity fuel filter (included) precedes the electric fuel pump coming from the gas tank.
Note that arrows indicate...
Note that arrows indicate flow direction on the filter and fuel pump. An existing hole in the C10 frame was used to route the fuel line. Never drill any extra holes into your truck that you don't have to.
As per a factory installation...
As per a factory installation the best place to mount the ECM (computer brain) is inside the cab on the passenger side. This meant a path had to be made for the wiring harness to pass from the engine compartment to inside the cab.
A very invasive hole needed...
A very invasive hole needed to be cut through the firewall to allow the two large ECM plugs to pass through.
Two 3/4-inch round holes were...
Two 3/4-inch round holes were cut to the right width and were connected to form an oval with a pneumatic hacksaw.
A real clean job, if I do...
A real clean job, if I do say so myself.
With Howell's special wiring...
With Howell's special wiring harness attached, the ECM rested nicely behind the glovebox door, and above the factory A/C unit.
This bung for the O2 sensor...
This bung for the O2 sensor (included) was welded onto the passenger side exhaust in between the exhaust manifold and the catalytic converter. All of the connecting plugs are labeled (white tagged) to simplify placement.
The knock sensor (included)...
The knock sensor (included) was installed by removing the block drain plug on the passenger side and threading it into in the drain plug's hole.
The stock Rochester Quadrajet...
The stock Rochester Quadrajet four-barrel carburetor was removed and the intake manifold's surface was scraped clean with a single-edged razor blade.
Then the billet aluminum TBI...
Then the billet aluminum TBI adapter plate was mounted onto the intake manifold separately from the TBI.
Next, the TBI throttle body...
Next, the TBI throttle body was mounted to the adapter plate, and the white-tagged plugs on the wiring harness were checked to make they were routed properly and could reach their intended connections (sensors, distributor, etc.).
With the engine set to TDC...
With the engine set to TDC (top dead center) the non-computer-controlled HEI-type distributor was removed by undoing the pinch-clamp at the distributor's base.
Before proceeding any further,...
Before proceeding any further, the hole for the distributor and the TBI were covered so no foreign objects could fall into the engine.
The stock mechanical fuel...
The stock mechanical fuel pump was removed and the hole covered with a block-off plate (included) and the stock fuel line was reconnected with a fuel line from the electric fuel pump, and joined to the TBI at the top (after this photo was taken).
The computer-controlled distributor...
The computer-controlled distributor from the kit was installed and timed at 10 degrees BTDC. Notice more white-tagged connections have been made as the wiring harness is positioned into place.
If care was taken to fit the...
If care was taken to fit the wiring harness properly, everything will appear cleanly routed such as these coolant sensor and knock sensor connections. After installing a new air cleaner to fit the TBI, the '75 was ready to fire up.