Automotive Wire Splicing

Sometimes you'll find a certain make and year of vehicle with a common problem that warrants a specific article, which covers both the cause and proper fix. In this case, we'll focus on a potentially baffling drivability symptom on the Hi-Lux pickup and 4Runner dating back to the mid-'80s. This malfunction typically appears on higher mileage, off-roaded (in the wet) and/or frequently "steam-cleaned" examples of these otherwise fine machines.

Old Faithfuls
Although aging and now considered vintage (since its replacement by the Tacoma model in the early/mid '90s), the Toyota Hi-Lux Pickup is still considered a viable light-duty workhorse. Its durable design and simple construction, along with low cost maintenance ease, make it an attractive alternative to costly, ungainly, fuel guzzling modern haulers. Many a parent has also appreciated these virtues when considering purchase of a "first drive" for their aspiring offspring. (Read that: "It stands up to the kind of abuse that inexperience dishes out.")


By the mid-'80s, the Hi-Lux (most folks just called it "the Pickup", since their were no other such offerings in the Toyota lineup until the T-100 and Tacoma) could be purchased with the electronic fuel-injected version of the OHC 2.4-liter 4-cylinder engine. The 4Runners of that period came with the same engine as standard equipment. (While it's true that Toyota also sold passenger car models with this engine/management combo, they don't seem to experience the problem about to be described, due to a slightly different design.)


If you have one of the Toyota trucks or SUVs mentioned above, and it experiences an intermittent or steady, single or multiple cylinder misfire, mostly while under acceleration that is definitely NOT caused by any other mechanical or ignition system malfunction, then read on. Relief is in sight.

Wiring Sub-Harness
The problem lies in the fuel injection wiring sub-harness as it runs from the upper portion of the right front inner fender to the intake plenum, just below the throttle body. The harness, about the size of a large human thumb and covered by common plastic corrugation and electrical tape, heads downward from the fender, looping upward to its anchor point at the intake plenum.