A Guide to Replacing Spark Plug Wires on the 1989-1996 Eagle Summit
If your Summit's engine is running rough, the fix could be simpler and cheaper than you think.
- For a stock 1989-1996 Eagle Summit, an NGK or Denso spark plug wire set is the best choice for OEM-quality fit and reliability.
- This is an easy DIY job; replace wires one by one to avoid mixing up the firing order.
- It is highly recommended to replace the spark plugs at the same time as the wires.
- Symptoms like rough idle, hesitation, and poor gas mileage are common signs of failing wires.
Is Your Summit Running Rough? Check Your Wires.
If your Eagle Summit has developed a rough idle, hesitates when you accelerate, or just feels down on power, you may have a problem with your spark plug wires. These wires are a common wear-and-tear item, and after decades of service, they are often due for replacement. Because the Summit shares its engineering with the Mitsubishi Mirage and Colt, parts are readily available and the job is straightforward for a DIY mechanic.
Symptoms of Failing Spark Plug Wires
Worn-out spark plug wires can cause a variety of noticeable engine problems. Here’s what to look and listen for:
- Rough Idle: The engine may shake or vibrate more than usual when stopped.
- Engine Misfires: You might feel a stumbling or jerking from the engine, especially under load. This happens when a cylinder fails to fire correctly.
- Hesitation on Acceleration: When you press the gas pedal, the car may stumble or lag before picking up speed.
- Reduced Fuel Economy: If you notice you're filling up the gas tank more often, inefficient combustion from weak spark could be the cause.
- Difficulty Starting: The engine may crank longer than usual before it starts, especially in damp weather.
- Check Engine Light: On newer models in this range, a persistent misfire can trigger the check engine light.
Pro Tip: The Dark Test
A simple way to check for bad wires is to start the engine in a completely dark garage. Look around the spark plug wires for any faint blue sparks jumping from the wire to a metal part of the engine. This is called 'arcing' and is a sure sign the wire insulation has failed and the set needs to be replaced.
Choosing the Right Aftermarket Wires
For the Eagle Summit, you don't need to hunt down an original Mopar part. High-quality aftermarket brands offer excellent performance and fit, with some being the original equipment supplier. Brands can be grouped into tiers based on quality and reputation among Mitsubishi/Eagle owners.
Tier 1: OEM-Quality Replacements
These brands are the most recommended for daily drivers. They provide the best combination of fit, performance, and long-term reliability.
- NGK: Widely considered the gold standard and a frequent original equipment manufacturer for Japanese vehicles. You cannot go wrong with an NGK set; they are known for perfect fit and reliable performance.
- Denso: Another top-tier Japanese brand with a reputation for quality that is on par with NGK. Denso is a trusted choice for a stock replacement.
Tier 2: Reputable Aftermarket
These brands offer good quality and are a solid choice if Tier 1 options aren't available.
- Standard Motor Products (Standard): A well-known aftermarket manufacturer that produces reliable ignition components.
- Walker Products: Offers a range of engine management parts and can be a suitable alternative.
Tier 3: Performance & Budget
These brands may fit your needs but require more consideration.
- Granatelli: Known for performance applications, often featuring thicker wires for modified engines with high-output ignition systems. This is generally overkill for a stock Summit.
- Karlyn STI: Typically a budget-friendly option. While functional, they may not have the same lifespan or perfect fit as Tier 1 brands.
A Note on OEM Parts
Original Chrysler/Mopar-branded wire sets for a vehicle of this age are likely discontinued or very difficult to find. Given that brands like NGK and Denso were often the original manufacturers, choosing one of their aftermarket sets provides OEM-level quality without the hassle.
Cost of Replacing Spark Plug Wires on a 1989-1996 Eagle Summit
| Part Type | Estimated Cost |
|---|---|
| New Aftermarket Spark Plug Wire Set | $23 - $91 |
| Shop Labor | $50 - $100 |
Frequently Asked Questions (FAQ)
Should I replace my spark plugs at the same time?
Yes, it is highly recommended. Spark plugs and wires have similar service lives and work together. Replacing them at the same time is a standard part of a tune-up and ensures the entire ignition system is refreshed.
Is this a difficult job to do myself?
No, this is a great beginner-level DIY task. The most important rule is to replace the wires one at a time. This prevents mixing up the firing order, which would cause the engine to run poorly or not at all.
What's the difference between 7mm and 8mm wires?
The measurement refers to the diameter of the wire. A thicker wire has more insulation, which helps prevent voltage arcing on high-performance engines. For a stock Eagle Summit, a standard 7mm wire from a quality brand like NGK or Denso is perfectly adequate.
Are there any recalls for the spark plug wires on my Eagle Summit?
No, searches of the National Highway Traffic Safety Administration (NHTSA) database show no recalls or technical service bulletins (TSBs) related to the spark plug wires for the 1989-1996 Eagle Summit.
Technical Specifications
OEM Part Numbers: MD997459
Typically a 4-wire set with 7mm diameter silicone jackets. Lengths are specific to the engine (1.5L, 1.6L, 1.8L, or 2.4L) and year.
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The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
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