Circuit Breakers And Fuses - Volvo 5.0OSiE-J Operator's Manual

5.0l, 5.7l, 8.1l sx-a, dps-a, xdp-b

Table of Contents

The spark plug wires are a special resistance

type. The core is carbon-impregnated linen. This

type wire is superior to copper core wire in its

resistance to crossfire; however, it is more easily

damaged than copper core. For this reason, pull

on the spark plug boots to remove the spark plug

wires, rather than pulling on the wire insulation. If

the wire is stretched, the core may be broken with

no evidence of damage on the outer insulation. If

the core is broken, it will cause misfiring. In the

case of wire damage, it is necessary to replace

the complete wire assembly since a satisfactory

repair cannot be made.

4. Clean ignition wires with a cloth moistened in ker-

osene, and wipe dry. Bend wires to check for brit-

tle, cracked or loose insulation. Defective

insulation may result in misfiring, cross-firing, or

spark to ground; therefore, defective wires must

be replaced.

5. If the wires are in good condition, clean any termi-

nals that are corroded. Replace any that are bro-

ken or distorted. Replace any wires with broken

or deteriorated cable nipples or spark plug boots.

6. Clean spark plugs.

Spark plugs that have carbon or oxide deposits

should be cleaned in a blast type spark plug

cleaner. Scraping with a pointed tool will not prop-

erly remove the deposits and may damage the

insulator. If spark plugs have a wet or oily deposit,

dip them in a degreasing solvent and dry thor-

oughly with compressed air. Oily plugs will cause

the cleaning compound to pack in the shell. Care-

fully follow the instructions of the manufacturer of

the cleaner being used. Clean each plug until the

interior of the shell and entire insulator are

cleaned. Avoid excessive blasting.

7. Examine interior of plug in good light. Remove

any cleaning compound with compressed air. If

traces of carbon or oxide remain in plug, finish the

cleaning with a light blasting operation. Clean fir-

ing surfaces of center and side electrodes with

several strokes of a fine cut file.

8. When spark plugs have been thoroughly cleaned,

carefully inspect them for cracks or other defects

that may not have been visible before cleaning.

9. Use a round wire feeler gauge to check the gap

between the spark plug electrodes. (Flat feeler

gauges will not give a correct measurement if the

electrodes are worn.) Adjust gap by bending the

side electrode only. Bending the center electrode

will crack the insulator. Setting the spark plug gap

to any other specification in an attempt to improve

idle or affect engine performance is not recom-

mended.

VPA 7748131 English 09-2007

10. See the diagrams for correct installation of spark

plugs and wires.

For proper engine performance it is very important

that the correct spark plugs be used. When installing

spark plugs, make sure that the threads in the cylinder

head and all surfaces on plugs and in cylinder heads

are clean. Tighten spark plugs the specified amount.

All engines use tapered seat plugs without gaskets.

DANGER! Do not operate engine if spark plug

boots or high-tension leads are torn or

cracked. This condition can allow external

sparks, which could ignite any fuel vapors in

the engine compartment.

Spark plug wires must be arranged between the dis-

tributor cap and spark plugs in the order of firing se-

quence. If spark plug wires are not correctly installed,

misfiring or cross-firing will result.

8.1liter engines use a distributorless ignition system

with one coil per cylinder. Refer to the section entitled

Technical Data on page 115 for correct firing order in-

formation.