Engine - Minimizing Crossfire Between Cylinders
83chevy15Number: 83-T-12
Section: VIy
Date: Dec., 1982
Subject: MINIMIZING CROSSFIRE 1981-82-83 VEHICLES EQUIPPED WITH 5.0L V8 ENGINES AND ESC SYSTEMS
"F" CAR - LEFT SIDE FIGURE 1:
"F" CAR - RIGHT SIDE FIGURE 2:
"G" VAN - LEFT SIDE FIGURE 3:
"G" VAN - RIGHT SIDE FIGURE 4:
"C-K" TRUCK - LEFT SIDE FIGURE 5:
"C-K" TRUCK - RIGHT SIDE FIGURE 6:
TO: ALL CHEVROLET DEALERS
The spark plug wire routing on 1983 5.0L V8 engines has been revised to minimize the possibility of crossfire between cylinders 5 and 7 on the left side and cylinders 4 and 8 on the right side.
It is important that this new routing be maintained during service, and restored to original configuration when wires are disconnected or replaced. The correct or recommended wire routings are shown in Figures 1 thru 6.
Crossfire occurs or has the tendency to occur in all V8 engines, but is enhanced because of the relatively high compression and the ESC spark retard system. Changing to a colder heat range spark plug, although directionally correct, does not always eliminate the condition.
Crossfire occurs usually in the following manner: when cylinder 5 fires, a voltage due to capacitive coupling between spark plug wires is impressed across the electrodes of the spark plug in cylinder 7.
The strength of this capacitive coupling depends on the distance between parallel wires and the length which they are routed parallel.
When the ESC system is retarding the spark timing due to detonation, the voltage requirement increases, thus increasing the crossfire potential.
When crossfire occurs, a customer might complain of such things as:
^ Detonation
^ Poor or erratic performance
^ Loss of power.
The following figures show the recommended spark plug wire routing for complaint vehicles.