straight up, the factory shielded this wire for a reason
Speaking as a tech who troubleshoots the "weird sh*t" for shops for a living,
... I would install a shielded wire while the harness is gutted.
I have seen several instances where a vehicle would randomly run poorly / pull timing / set knock sensor codes when the shielding was missing and/or damaged.
One instance in particular sticks in my mind.
It was a smallblock swap into an older 4x4 that used a factory gm tbi harness.
The earlier versions of some of those engines didn't shield that wire
... and it must be said that hundreds of thousands of vehicles with those harnesses with an unshielded knock sensor wires go down the road, no worries at all.
However, adding a high energy coil/ignition system would occasionally cause some problems with the electronic spark control system
(est was an early attempt to control ignition timing with an ecu, as opposed to just centrifical and vaccumm advance/retard)
On that particular vehicle, the owner swapped in a v8 where a 4 banger had been.
He gutted the harness to eliminate a few of the emission controls/unecessary "fluff"
Thing would start and run okay, but occaisionally the exhaust manifolds would get so hot it would melt the plug wires/boots, and he said it run "weird".
... a timing light told the tale
The timing was all over the place.
After investigating the usuall suspects (applecored distributor drive gear/timing chain etc) I zero'd in on the est system.
... got to learn all about how the engineers did things in the stone age of electronic engine controls /ubbthreads/images/graemlins/idea.gif
After swapping a few components (with known good used pieces) on a whim, I ran an external knock sensor wire outside the harness back to the ecu
vi~fawkin~ol~a! great succcess![/i]
I used a bare wire for testing, but that looked "scabby" on his build (man took pride in his work /ubbthreads/images/graemlins/smile.gif )
After giving the situation some thought I visited a car stereo / home theatre buddy and gadged some quality shielded video cable.
Ran that inside his harness bundle, and terminated the shielding to ground inside the vehicle
never had another bit of trouble with that system
One thing to be mindfull of is that home stereo stuff is not rated for high temperatures!
On a 4g installed in a "standard" configuration, the wire is away from *most* of the serious heat, but there is some heat soak in the engine compartment at engine shutdown.
A little thought and some external loom rated for the temps found in engine compartments should get things up to snuff
/ubbthreads/images/graemlins/cliffs.gif
just because you can get away with it, doesn't mean you should!
If you don't know a "cool guy" in the business out there, I can source the materials for you at cost.
do it once, do it right, and boost on /ubbthreads/images/graemlins/grin.gif
