Ignition Coil and Iridium Spark Plugs for Volvo S90 (1997-1998) 2.9L

Direct-Fit Ignition Coil and Iridium Spark Plug Kit for 1997-1998 Volvo S90

What it Does: The ignition coil and iridium spark plug kit restores primary combustion efficiency, stabilizes idle, and eliminates secondary ignition misfires on the 1997-1998 Volvo S90.

The Stock Volvo S90 Thermal Breakdown and Voltage Leakage

The naturally aspirated B6304S 2.9L inline-six relies on an individual coil-on-plug architecture positioned beneath a plastic spark plug vanity cover. Over decades of heat cycling, this recessed layout traps severe cylinder-head heat, causing the factory epoxy encapsulation and silicone plug boots to degrade. Dielectric breakdown follows, resulting in micro-arcing against the magnesium cam cover, unburnt fuel wash, intermittent rough idle, and persistent P0300-P0306 misfire codes under load. Concurrently, standard nickel-core plugs erode prematurely, widening the electrode gap and overworking aging primary coils.

The Engineering Solution

This comprehensive overhaul kit features six high-dielectric pencil ignition coils matched with fine-wire iridium spark plugs to permanently resolve high-temperature ignition failure. Each coil housing utilizes reinforced, high-temperature thermoplastic PBT with high-grade copper windings to maintain peak magnetic saturation and constant secondary kilovolt output across the entire rev range. The companion iridium plugs feature a laser-welded 0.6mm ultra-fine center electrode that drastically lowers the required striking voltage while resisting thermal quenching. Paired with high-tear silicone dielectric boots, this kit restores crisp throttle tip-in, uniform flame front propagation, and reliable cold-start combustion.

Technical Specifications

Compatibility

• 1997 Volvo S90 Base Sedan 2.9L L6 (B6304S)
• 1998 Volvo S90 Base Sedan 2.9L L6 (B6304S)

Frequently Asked Questions

Does this fit the 964 Chassis S90?
Yes, this is a direct fit for the 1997-1998 Volvo S90 equipped with the B6304S engine.

Are the iridium spark plugs pre-gapped for the B6304S inline-six?
Plugs arrive pre-gapped to factory specifications; always confirm gap using a feeler gauge prior to torquing to avoid electrode damage.

The Volvo European Precision Standard

Engineered to exact Motronic system impedance parameters, this complete secondary ignition assembly preserves factory European diagnostic compliance and delivers zero-CEL, OE-level ignition timing consistency.