How to Winterize Your EFI System and Protect Your Investment
Expert Tips for Winterizing Your Aftermarket EFI System
- Fuel Stabilization is Non-Negotiable: Modern ethanol-blended fuels are hygroscopic (they attract water), which can wreak havoc on high-pressure fuel injection systems during long-term storage.
- Seal and Protect: Protecting electrical connectors from corrosion and sealing the throttle body from moisture and pests is critical for a “first-key” start in the spring.
- Voltage Matters: Low battery voltage during winter can lead to corrupted ECU memory or sensor failure upon startup.
- Borla Quality: Investing in high-grade EFI Components now prevents costly repairs later.
As the temperature drops and the salt trucks begin their rounds, it’s time to move your classic from the street to the garage. While winterizing a carbureted engine is a familiar ritual, aftermarket EFI systems require a slightly different approach to ensure their sophisticated electronics and high-pressure plumbing remain in peak condition.
As a performance specialist, I’ve seen too many owners face clogged injectors or “ghost” electrical issues come April. Here is the expert-level checklist to winterize your EFI-equipped build the right way.
Electrical Integrity: Seal and Inspect Your Sensors
Corrosion is a silent killer of EFI performance. Even in a climate-controlled garage, ambient humidity can lead to oxidized terminals and galvanic corrosion on pins and sockets. This buildup increases electrical resistance, resulting in erratic sensor signals, data “noise,” or a complete “no-start” condition in the spring.
- Inspect Your TPS: Your Throttle Position Sensor is the “eyes” of your ECU. If you are running a high-precision TPS Hall Effect sensor, ensure the connector is seated tightly. These non-contact sensors are incredibly durable, but they still require a clean electrical signal to function.
- Check Mechanical Connections: For traditional setups using a TPS Clockwise Black Panel style sensor, verify that the mounting hardware hasn’t vibrated loose over the season. A small dab of dielectric grease on the external connector seals can prevent moisture intrusion during the damp winter months.
Combat the Ethanol Threat
The biggest enemy of a parked vehicle isn’t the cold; it’s the fuel. Most gas station pump fuel contains up to 10% ethanol. Ethanol attracts moisture, leading to phase separation and the formation of a corrosive “glop” that can plug the tiny orifices of your fuel injectors.
- Top it Off: Fill the tank to 95% to leave minimal room for air (and moisture) to condense inside.
- Stabilize: Add a high-quality fuel stabilizer designed for EFI systems.
- Circulate: After adding the stabilizer, run the engine for at least 15 minutes. This ensures the treated fuel reaches the fuel rails, injectors, and the regulator.
Throttle Body & Sensor Care
Your aftermarket EFI system relies on clean air and precise sensor data. Residue left behind during the driving season can harden over winter.
- Clean the Plate: Use a dedicated EFI-safe cleaner to wipe down the throttle plates. Avoid harsh chemicals that can damage the specialized coatings on modern throttle bodies.
- Check the IAC: Ensure the Idle Air Control (IAC) motor isn’t gummed up.
- Seal the Intake: Rodents love nesting in intake manifolds. Use a specialized plug or a clean, lint-free shop rag (with a bright “Remove Before Start” tag) to seal the throttle body intake.
Electrical Integrity: Seal the Connections
Corrosion is a silent killer of EFI performance. Even in a garage, humidity can lead to “green crusties” on pins and sockets.
- Dielectric Grease: Check critical EFI Components like your O2 sensor lead and coolant temp sensor. A small dab of dielectric grease on the connector seals can prevent moisture intrusion.
- The Battery: Modern ECUs can have a small “parasitic draw.” A battery tender is mandatory. If a battery drops below 10 volts, it can sometimes cause the ECU to lose “learned” fuel trims or, worse, spike the electronics when you try to jump-start it in the spring.
Borla Induction: EFI Winter Storage “Must-Do” Checklist
| Task | Why it Matters |
| Seal ITB Air Horns | Borla’s Individual Throttle Bodies are precision-machined. Use specialized covers or lint-free cloths to prevent dust, moisture, or pests from entering the intake tracts. |
| Lubricate Linkage Kits | Precision linkage kits should be cleaned and lightly lubricated with a dry-film lubricant to prevent binding or surface oxidation during storage. |
| Exhaust/O2 Protection | Seal tailpipes to prevent “chimney effect” moisture from reaching your wideband O2 sensors, which are critical for Borla’s self-tuning ECUs. |
| Fuel Rail & Line Check | High-pressure EFI fuel systems operate at 45-60+ PSI. Inspect all fittings and soft lines for signs of “checking” or leaks; a minor leak under pressure is a major fire hazard. |
| TPS Calibration Check | Before final shutdown, use your software to verify the TPS signal is smooth. This ensures your “learned” data is accurate before the ECU goes into hibernation. |
| Treat Ethanol Fuel | Use a stabilizer to prevent phase separation in the tank, which can clog the fine internal filters of high-performance injectors. |
Get Your Build Ready for Hibernation
Don’t let a small issue turn into a major headache next spring. If you noticed your AFR (Air/Fuel Ratio) drifting during those final fall cruises, now is the ideal time to swap out components while the car is already headed for the jack stands.
Ensure your system is sealed and secure by browsing our professional-grade EFI Components. From fresh sensors to high-pressure fuel filters, we have the hardware you need to ensure a flawless first start when the weather breaks.
Have questions about specific storage procedures for your setup?
Our Support team is here to help you safeguard your performance.
