...so I am thinking this recommendation by Schurkey is legit and would like to pursue it further .
The problem is, after searching for how to run the plug wires for a SBC I get diagrams that show a variety of ways, and none that show the wire looms. Like the OP, I also have a 94' K1500 5.7 ( Mine is a GMC suburban ) but need to know where I can get the right spark plug wiring diagram for the wires and looms ?
Hello name,
There actually is 1 best way, and many many suboptimal ways to route the spark plug
wires on a SBC. Especially the ones in the GMT400 family, for the way these engines are
tasked vs the emissions calibration the secondary side of the ignition system is run right
up against the limits of the spark plug wire harness's ability to reliably contain/route the high
voltage pulses to the intended destination.
And if you want to see a visual version of the old 'Telephone Game' (
children's game demonstrating cumulative error)
just wander around at the next local Show & Shine and look at how many different
ways the spark plug wires can be hung off of a 1st-gen SBC. Lot's of creativity,
artistic vision, or evidence of making it up as you go along, but at the same time a lot of reliability
vs routing rules are ignored/broken.
****
So in order to get the best guidance on this subject, let's go to the source and see how the General's
engineers recommended routing these wires in order to minimize cross-firing, shortened lifespan cats,
higher emissions, etc. Since you are working on a '94, I opened that year's FSM and did a global Find (
Ctrl F)
on 'spark plug wires.'
Here's a detail on the passenger side from the FSM:
You must be registered for see images attach
And here's a detail illustration of the driver's side spark plug wiring:
You must be registered for see images attach
Note: Take a careful look at the effort to keep the wires from both firing order &
physical neighbors #5 & #7 as far apart as possible in the factory loom. There's an
important message in this illustration, direct from the people paid to worry about
this stuff for a living. (!)
Note: In the 1st attachment I took a big picture screen snap of what it's like to
search the '94 FSM for every instance of 'spark plug wires'. As you can see in the
upper right hand corner there were 20 instances of this phrase in the book, and
4/20 gave me what I was looking for. If you haven't given yourself the gift of
using the Factory Service Manual in order to keep your GMT400 on the road, then
run, don't walk over here to the forum's FSM cache and download a free copy for
yourself. (
88+ GMT400 FSM cache)
****
But wait, there's more. I saved the best for last. There is a gentleman on this forum
who combines top-notch workmanship with way better than original levels of power
production. His work is his signature, and my great Uncle Hank would approve.
Follow this link to this reply, and study carefully how he routed his wires.
Hint: It's among the closest in the real world that I've seen to the guidance
out of the General's books. :0) (
L31MaxExpress photos of his spark plug wire installation.)
NOTE: This guy routinely monitors his live data, including the misfires, so
his implementation details are based on hard data instead of wishful thinking.
****
Hope all this proves helpful in your efforts to eliminate those random misfires.
Best of luck --