Choosing the Right Distributor for Your 1987 GMC R1500
Keep your classic GMC truck's ignition system reliable with the correct new aftermarket distributor.
- A failing distributor on a 1987 R1500 often causes stalling when hot, misfiring, or a no-start condition.
- You must use a timing light to set the ignition timing after replacing the distributor.
- For reliability, choose a quality new aftermarket unit from a brand like WAI Global or MSD over a remanufactured one due to common quality control issues with the latter.
- Ensure you are buying a small-cap distributor for a TBI engine, not the large-cap HEI for older carbureted engines.
Is Your R1500's Distributor Failing?
The distributor in your 1987 GMC R1500 works hard under the hood. Over time, heat and high voltage cause the internal parts to wear out. The most common failure points are the ignition control module (ICM), the pickup coil, and the cap and rotor. A failing distributor can leave you stranded. Watch for these signs:
- Engine Stalls When Hot: The truck runs fine when cold but sputters and dies as it warms up. It might restart after cooling down for a while.
- No-Start or Hard Starting: The engine cranks but won't fire up, or takes a long time to start.
- Rough Running and Misfiring: You may feel a shudder or hesitation while driving, especially when accelerating. The engine might also backfire.
- Check Engine Light: Ignition problems can trigger the check engine light.
Choosing the Right Aftermarket Distributor: Brand Quality Tiers
When shopping for a new distributor, you'll find a wide range of quality and price. For your 1987 R1500, it's best to avoid the cheapest options, as forum users often report issues with poor quality electronics and incorrect ignition advance curves in budget units. It's also wise to be cautious with remanufactured parts, as quality can be inconsistent.
Aftermarket Brand Tiers for 1987 GMC R1500
| Tier | Brands | Best For | Notes |
|---|---|---|---|
| High-Performance / Heavy-Duty | MSD, FAST | Performance, towing, and maximum reliability. | These brands are known for high-quality components that provide a strong, reliable spark. They are more expensive but are considered a significant upgrade, even for a stock engine. |
| Standard Replacement (New) | WAI Global, Replacement | Daily driving and stock replacement. | Brands like WAI Global manufacture 100% new distributors that are designed to meet or exceed original factory specifications. They offer a good balance of quality and value for a truck that is not highly modified. |
| Remanufactured | Cardone | Budget-conscious repairs. | Cardone is a major supplier of remanufactured parts, but online forums show very mixed reviews. Some owners report premature failures or receiving defective parts. While they can be a cost-effective option, there is a higher risk of quality control issues compared to a new unit. |
Pro Tip: The distributor for your 1987 TBI engine is a small-cap design with an external coil. Do not confuse it with the large, all-in-one HEI distributors found on older, carbureted GM engines.
Frequently Asked Questions
Do I need a special tool to replace my distributor?
Yes. After you install the new distributor, you absolutely must set the ignition timing using a timing light. You will also need a special distributor wrench (an offset 9/16" or 15mm wrench) to easily reach the hold-down bolt.
Can I just replace the parts inside my old distributor?
Yes, you can replace individual components like the ignition control module, pickup coil, cap, and rotor. However, if the distributor shaft has excessive play or the housing is damaged, replacing the entire assembly is the better long-term repair. Given the age of the truck, a complete new unit ensures all components are fresh.
What is the most common cause of distributor failure on this truck?
The ignition control module (ICM) located inside the distributor is a very common failure point. It is sensitive to heat, which is why stalling when the engine is hot is a classic symptom. Corrosion on the module's ground connection is also a known problem that can cause a misfire.
Is there a recall on the distributor for my 1987 GMC R1500?
No. Searches of the National Highway Traffic Safety Administration (NHTSA) database show no recalls specifically for the distributor on the 1987 GMC R1500. Major GM ignition recalls in recent years were for ignition *switches* on much newer vehicles and do not apply to your truck.
Technical Specifications
OEM Part Numbers: 1103678 1103717 1103838
Computer Controlled HEI/EST, Small Cap, External Coil, V8 Engine Application
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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.
- GMC R1500: