1985-1991 Chevrolet Caprice Ignition Control Module Replacement Guide
Solve stalling and no-start problems by choosing the right ignition module for your Caprice.
- A stalling engine when hot is the number one sign of a failing ignition module in a 1985-1991 Caprice.
- You MUST apply thermal grease to the back of the new module, or it will fail quickly from overheating.
- Choose a quality aftermarket brand like Delphi or Standard Motor Products (non-economy line) for best results.
- This is a DIY-friendly repair that requires basic tools and can be completed in under an hour.
Is Your Caprice Stalling When It Gets Hot?
One of the most common problems with the ignition control module in the 1985-1991 Chevrolet Caprice is engine stalling after the car has warmed up. You might be driving along without any issues, but when you come to a stop, the engine suddenly dies. It might refuse to restart until it has cooled down for 15-30 minutes. This happens because the module is failing and cannot handle the heat inside the engine bay. Other signs of a bad module include a car that cranks but won't start, a rough idle, engine misfires, and poor acceleration.
🎬 Watch: A complete guide to bad ignition module symptomsChoosing the Right Aftermarket Ignition Module
For a classic car like the '85-'91 Caprice, original AC Delco parts can be hard to find. Aftermarket parts are the most common choice. However, quality varies greatly, and choosing the wrong one can leave you stranded again. Cheap, no-name modules are known to fail very quickly. It is best to choose a quality part from a known brand.
Aftermarket Brand Quality Tiers
| Tier | Brands | Description |
|---|---|---|
| OEM-Quality Aftermarket | Delphi, Standard Motor Products (SMP) | Delphi was an original parts supplier for GM, and their parts are generally considered reliable replacements. Standard Motor Products (SMP) is a well-respected aftermarket brand with a long history of making quality ignition parts for GM vehicles. When buying Standard, make sure to get the standard red box part, not the economy 'T-Series' green box part, which has a reputation for lower quality. |
| Performance / Value Brands | Accel, Proform | These brands are often marketed for high-performance applications. For a stock Caprice, they may be unnecessary. Forum discussions show mixed reviews on reliability for daily driving, with some users experiencing early failures. They can be a valid option, but may not offer the same long-term reliability as top-tier aftermarket brands. |
Pro Tip: Don't Forget the Thermal Paste!
The single most important step when replacing your ignition module is to apply the included thermal grease to the metal bottom of the new part. This grease helps transfer heat away from the module to the distributor body. If you forget this step, the new module will overheat and fail very quickly, sometimes in a matter of minutes.
🎬 See how to install a Caprice module the correct wayFrequently Asked Questions (FAQ)
Why does my Caprice stall when it's hot but restart when it's cold?
This is the classic symptom of a failing ignition control module. As the module gets hot, its internal electronics start to fail, which cuts off the spark to the engine. After it cools down, the electrical connection is temporarily restored, and the car will start again until it heats up.
Are there any recalls on this part?
No. Searches of the National Highway Traffic Safety Administration (NHTSA) database show no recalls for the ignition control module on the 1985-1991 Chevrolet Caprice. Later model year Caprice vehicles had recalls for the ignition *switch* (the part you put your key in), but this is a completely different part and does not apply to this generation.
Can I replace the ignition module myself?
Yes, this is a job that most DIY mechanics can handle. It is located inside the distributor under the cap and rotor. You will need basic hand tools. The job involves removing the distributor cap, the rotor, and then two small screws that hold the module in place. The most difficult part is often the tight space between the back of the engine and the firewall.
🎬 Watch this walkthrough for replacing a GM ignition moduleDo I need a special tool to replace the module?
Usually, no special tools are required. A set of screwdrivers and small sockets will be enough. The screws holding the module are often a 7/32" or similar small size. The most important 'tool' is the packet of thermal grease that should come with your new module.
Helpful Videos
Technical Specifications
OEM Part Numbers: 1906603 D1906
4-Pin HEI Ignition Control Module
We Have This Part in Stock
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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