GMC S15 Fuel Injector Guide: Understanding, Replacing, and Choosing Parts for 1985-1990 Models
Keep your classic S15 running smoothly by understanding its unique Throttle Body Injection (TBI) system.
- Your S15 has a Throttle Body Injection (TBI) system, not modern multi-port injectors.
- Always replace injectors as a set to ensure balanced engine performance.
- Verify the part is correct for your engine (2.5L, 2.8L, or 4.3L) as flow rates differ.
- Using ACDelco or Standard Motor Products is recommended for reliability; budget remanufactured parts have mixed reviews.
Signs of a Failing Fuel Injector in Your S15
The fuel injectors on the 1985-1990 GMC S15 are part of a Throttle Body Injection (TBI) system. This means instead of individual injectors for each cylinder, your truck has one or two injectors mounted in the throttle body. When they start to fail, the symptoms are usually noticeable. You might experience a rough or sputtering idle, engine misfires, and a general feeling of the truck running poorly. Some owners report issues like the engine cranking but not starting, or starting and then immediately stalling, because the injectors aren't delivering fuel correctly. A strong smell of gasoline under the hood can also be a sign, indicating a leaking injector 🎬 See what leaking TBI fuel injectors look like in action or a bad O-ring seal.
Is It the Injector or Something Else?
Problems like a rough idle or no-start condition on these trucks can also be caused by other parts, such as a bad fuel pressure regulator, a clogged fuel filter, or issues with the ignition system. It's a good idea to check fuel pressure and look for spark before deciding 🎬 Watch: How to diagnose a TBI engine that won't start the injectors are the problem. Forum users often mention testing or replacing the Ignition Control Module (ICM) and Hall Effect sensor for similar no-pulse or no-start issues.
Choosing the Right Aftermarket Fuel Injector
When shopping for a new fuel injector for your S15, you'll find several brands. It's important to choose a quality part to avoid doing the job twice. Since these injectors are critical for engine operation, quality and reliability should be your main focus.
Brand Quality Tiers
- Top Tier (OEM Equivalent): ACDelco is the original equipment manufacturer for GM. Choosing ACDelco ensures you get a part that meets the original factory specifications for fit, form, and function. Mechanics and owners consistently recommend ACDelco for critical parts to ensure reliability.
- Mid-Grade (Trusted Aftermarket): Standard Motor Products (Standard Ignition) is a well-respected brand that has been making fuel and ignition parts for decades. They are known for strict quality control and are a reliable choice for owners who want a quality part that may be more affordable than the OEM option.
- Economy (Budget-Focused): Brands like GBR Fuel Injection offer remanufactured injectors at a lower price point. However, owner experiences with remanufactured injectors can be mixed. Some have success, while others report premature failures, such as injectors being stuck open right out of the box or failing after a few months. While the price is tempting, be aware of the potential for quality issues.
A Note on Engine Differences
The 1985-1990 S15 was available with different engines, including the 2.5L I4, 2.8L V6, and 4.3L V6. Fuel injectors can have different flow rates for each engine. Always verify that the part you are ordering is correct for your specific engine and year to avoid performance problems.
| Brand Tier | Example Brands | Estimated Price Range (Per Injector) |
|---|---|---|
| Top Tier | ACDelco | $80 - $175 |
| Mid-Grade | Standard Ignition | $85 - $100 |
| Economy (Remanufactured) | GBR Fuel Injection | $35 - $60 |
Frequently Asked Questions
Do I need to replace both injectors at the same time?
It is highly recommended. Mechanics suggest replacing fuel injectors as a set. If one injector has failed due to age or contamination, the other is likely not far behind. Replacing them together ensures a balanced fuel delivery and consistent performance.
Is replacing a TBI fuel injector a DIY job?
Yes, for someone with basic mechanical skills, this is a feasible DIY job. The injectors are located on top of the engine and are relatively easy to access after removing the air cleaner assembly. The process involves relieving fuel pressure, disconnecting fuel lines and electrical connectors, unbolting the injector pod, and swapping the injectors. 🎬 Watch this step-by-step TBI fuel injector and filter replacement guide Always use new O-rings and seals, and lubricate them with a little clean engine oil or gasoline before installation to ensure a proper seal.
Are there any recalls for the fuel system on these trucks?
Searches on the NHTSA database did not show any open recalls specifically for the fuel injectors on the 1985-1990 GMC S15. However, recalls can be issued for other fuel system components, so it's always a good practice to check for any open recalls on your specific vehicle using its VIN.
What are TSBs and are there any for these injectors?
A Technical Service Bulletin (TSB) is a notice from the manufacturer to dealers about common problems and recommended repairs. While no specific TSBs for the 1985-1990 S15 injectors were found in the search, GM has issued general bulletins about fuel injector issues. For example, TSB 18-NA-137 discusses fuel odors from leaking O-ring seals, and TSB 20-NA-098 emphasizes using the correct part number to match flow rates when replacing injectors.
Helpful Videos
Technical Specifications
OEM Part Numbers: 17111814 17112460 17111986 217336 217-336
System Type: Throttle Body Injection (TBI). Number of Injectors: 1 (2.5L) or 2 (2.8L, 4.3L). Terminal Type: 2-Blade Connector.
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.
- GMC S15: