It's no mistake that there are two stories featuring my '75 C10 clone of the '79 C10 Americruise truck in this issue, and that they both have to do with controlling the delivery of fuel to the truck's engine. It's all about the green. No, not the trendy kind of green every slick marketer on the planet is slithering up to, but the green in your wallet. What we are about to demonstrate should give your truck better gas mileage out on the highway. We'll be helping with the energy crisis, but more importantly you'll likely be saving yourself from a speeding ticket. And that's the kind of green we like to save.
Back to the two stories approach, it's because there are some things that definitely should be attempted at the same time if at all possible. This is especially true when it comes to routing in a new wiring harness to supplement your truck's existing harness with new circuits. Have you ever noticed how some people have a wiring harness lurking in their truck that makes a big bowl of twisty spaghetti look like a perfect straight line? That's because the wiring harness has been hacked into many times without any consideration of what it does to the harness' integrity or what the job looks like. That said, it was a no-brainer to install a Dakota Digital cruise control system into the '75 at the same time as Howell Developments' TBI fuel injection system (page 47).
Both operations start under the hood at the fuel induction point and rely on computer controls that must be placed within the cab, or at least 10 inches away from the engine's ignition coil. Since Dakota Digital's cruise control system is a universal kit that comes with excellent instructions on how to do a basic installation and set it up, we'll focus mainly on the topics that deal exclusively with installing it into a '73-87 Chevrolet C10 or GMC. In particular we'll be paying special attention to doing a clean installation of the control module and routing the wiring harness to blend in with the existing harnesses.
As with all mechanical work...
As with all mechanical work that involves the electrical system, step 1 is to disconnect the battery.
Here's the Dakota Digital...
Here's the Dakota Digital electric servo that comes complete with the wiring harness attached.
Bearing in mind Dakota Digital...
Bearing in mind Dakota Digital specifies the cruise control servo must be mounted at least 10 inches away from the ignition coil we searched for a good mounting spot to make sure the control cable would be routed free of kinks or snags.
The ideal spot appeared to...
The ideal spot appeared to be alongside of the opening cut for the TBI harness installed previously.
A step that if overlooked...
A step that if overlooked can present problems deeper into the job was to close the hood and make sure a clearance problem wouldn't occur when the hood was shut.
The same opening for the Howell...
The same opening for the Howell Developments' TBI fuel injection harness will work equally well for routing the Dakota Digital cruise control harness into the cab.
Note the cruise control harness...
Note the cruise control harness was kept handy to test fit as the hole was cut.
Once it is determined that...
Once it is determined that both the Howell TBI and Dakota Digital cruise control system operate trouble free this hole will be sealed-up from the elements with a non-hardening sealant that can easily be re-opened for future use.
Although the Dakota Digital...
Although the Dakota Digital wiring harness comes attached it needs to be wrapped with protective tubing (included) before it can be routed into the cab (installed).
We've found the absolute best...
We've found the absolute best way to do a clean job of installing parts that require drilling new holes is to make a pattern.
A piece of heavy construction...
A piece of heavy construction paper was traced around the profile of the cruise control servo and then double-checked by measuring with a square.
Although our mounting location...
Although our mounting location didn't require the use of the bracket Dakota Digital supplied for a freestanding location we decided the bracket would make an excellent backing plate.
A cutoff wheel was used to...
A cutoff wheel was used to make quick work out of chopping the bracket down to size.
The bracket was also a great...
The bracket was also a great template to use for marking the holes to drill in the firewall.
After identifying marks were...
After identifying marks were made to ensure the template was positioned correctly it was taped into place and the two 1/4-inch holes were drilled.
A chunk of non-hardening putty...
A chunk of non-hardening putty (included) was placed on top of the servo unit and then the hood was closed to measure the gap left between the servo unit and the closed hood.
The easiest way we found to...
The easiest way we found to stuff these oversized plugs through the opening was staggered, one-at-a-time.
Notice in this photo a space...
Notice in this photo a space was left next to the Dakota Digital servo to extract the Lokar transmission dipstick without interference.
Once it was established that...
Once it was established that the cruise control cable operated freely, the next step was to set up the throttle linkage as explained in the instruction sheet.
The cruise control cable must...
The cruise control cable must be checked for proper travel by setting it to the idle position and then to full-throttle and then dividing the distance.
The vertical, black-rubber...
The vertical, black-rubber plug on the right side of the servo is easily removed to adjust settings as described in the instruction manual.