fits model: H5. make: Gmc, Chevy, Chevrolet.

( Brand: Gm ), ( Manufacturer Part Number: 17113569 ), ( Type: Throttle Body )
The **Genuine OEM 17113569 Throttle Body Assembly** for the **1988 1993 GMC/Sierra 1500, 1988 1993 Chevrolet C/K Trucks, and 1988 1993 Chevrolet Blazer/S10 Pickup** is a precision-engineered component designed to regulate airflow into the engine s intake manifold, ensuring optimal performance and fuel efficiency. This **Throttle Body Injection (TBI) assembly**, part of the **H5 engine family** (commonly found in the 4.3L V6), is manufactured to exact factory specifications, guaranteeing a seamless fit and reliable operation. Crafted from high-quality materials, including durable plastic and precision-machined metal components, this throttle body features a **single-point fuel injection system**, where fuel is introduced directly into the intake airflow before it enters the engine cylinders. The assembly includes a **throttle plate** with a smooth, wear-resistant coating to prevent sticking, a **throttle position sensor (TPS)** for accurate engine control module (ECM) feedback, and a **vacuum port** for proper engine vacuum management. This component is essential for maintaining proper idle stability, throttle response, and overall drivability, making it a critical replacement part for vehicles experiencing rough idling, stalling, or poor acceleration. Whether replacing a worn-out original unit or upgrading an aftermarket installation, this **direct-fit OEM throttle body** ensures compatibility with the vehicle s factory wiring harness and intake system, delivering the same performance as the original equipment. Ideal for mechanics, DIY enthusiasts, and fleet operators, this part is a straightforward, no-compromise solution for restoring or maintaining the reliability of your **GMC/Sierra or Chevrolet** truck or SUV.
### **Pros and Cons of Buying a 1985 GMC/Chevrolet TBI H5 Throttle Body Injection (TBI) V8 (350ci/5.7L) Engine**
#### **Overview**
The **1985 GMC/Chevrolet TBI H5 engine** (a 350ci V8 with throttle body injection) was a transitional powerplant between carbureted and modern fuel-injected engines. It was used in full-size trucks, SUVs, and some passenger cars. While it has its advantages, it also comes with significant drawbacks, especially for modern use.
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### **Pros**
1. **Proven Reliability (When Maintained Properly)**
- The **350ci V8** is a well-known, durable engine design that has been used for decades with proper maintenance.
- Many examples last **200,000 miles** if regularly serviced, with oil changes, valve adjustments, and minor repairs.
- Aftermarket support is strong, with readily available parts and tuning options.
2. **Strong Towing & Hauling Capability**
- With **250 300 hp** (stock) and **350 400 lb-ft of torque**, it was well-suited for heavy-duty truck applications.
- Can handle **towing, payload, and rough use** better than many modern small-block engines if built correctly.
3. **Affordable to Purchase & Repair**
- Used **1985 TBI H5 trucks** are often **cheap** compared to modern full-size trucks, making them a budget-friendly option.
- Parts (belts, rods, heads, etc.) are **far cheaper** than those for newer engines.
- Labor costs are lower since mechanics are familiar with the design.
4. **Easy to Modify & Upgrade**
- **Aftermarket support is extensive** performance parts (intakes, exhausts, camshafts, fuel pumps) are widely available.
- **TBI can be upgraded to EFI (Electronic Fuel Injection)** with relative ease, improving reliability and performance.
- **Big-block swaps** (like a **454ci or 466ci**) are common and can drastically increase power.
5. **Simple & Straightforward Design**
- **No complex turbocharging or direct injection** easier to diagnose and repair than modern turbocharged engines.
- **Mechanical fuel pump** (unlike modern electric pumps) is more forgiving in cold weather.
- **No EGR or complex emissions systems** (compared to later TBI models), reducing long-term maintenance headaches.
6. **Good for Off-Road & Heavy Use**
- **Durable construction** makes it suitable for **off-roading, towing, and rough terrain** if properly maintained.
- **No electronic failure points** (unlike some modern engines with computer-controlled systems).
7. **Fun to Drive (When Running Well)**
- **Strong low-end torque** gives a **responsive, drivable feel** especially with a manual transmission.
- **V8 sound** is satisfying for enthusiasts who enjoy classic truck power.
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### **Cons**
1. **Poor Fuel Economy**
- **12 15 MPG highway** is **terrible by modern standards** (even compared to older trucks).
- **TBI systems are inefficient** compared to modern port-injected or direct-injected engines.
2. **Reliability Issues with Neglect**
- **Oil leaks** (valve cover, rear main seal, oil pan gaskets) are common if not maintained.
- **Rod bearings and main bearings** can wear out if oil changes are skipped.
- **Distributor and ignition issues** (points, coils) can cause misfires if not serviced.
- **TBI sensors (MAP, TPS, IAC) fail over time**, leading to rough idling or stalling.
3. **Emissions & Modern Compliance Problems**
- **No OBD-II or modern emissions controls**, making it **illegal in many areas** without modifications.
- **Smog check failures** are common in states with strict emissions laws.
- **No EGR or PCV systems** (later TBI models had these), leading to **carbon buildup and rough running**.
4. **Throttle Body Injection (TBI) Limitations**
- **Less precise fuel delivery** than port injection, leading to **poor cold starts and rough idle**.
- **Fuel pump reliability** is an issue many TBI pumps fail, requiring frequent replacements.
- **No individual cylinder control**, meaning **one bad sensor or wire can ruin the whole system**.
5. **Modern Driving & Technology Issues**
- **No modern diagnostics** troubleshooting requires **vacuum checks, scope work, and mechanical knowledge**.
- **No cruise control compatibility** (unless aftermarket is installed).
- **No modern infotainment or safety features** (if buying a newer model with these, it may require a full rebuild).
6. **High Maintenance Requirements**
- **Valve adjustments every 30K 50K miles** (unlike modern engines with hydraulic lifters).
- **Distributor and ignition components** need frequent inspection.
- **Fuel system cleaning** is necessary to prevent clogged injectors (even though they re throttle-body, fuel quality affects performance).
- **Exhaust manifolds crack** over time, leading to leaks.
7. **Resale Value & Insurance Costs**
- **Low resale value** even a well-maintained TBI truck won t hold value like a modern diesel or turbocharged engine.
- **Higher insurance premiums** due to **lower safety ratings, older construction, and higher risk of breakdowns**.
8. **Environmental & Legal Restrictions**
- **Many states ban TBI engines** in favor of cleaner alternatives.
- **Smog check failures** can be expensive to fix (often requiring **EFI conversion**).
- **No modern emissions testing compatibility** some areas require **EPA-certified modifications**.
9. **Performance Limitations (Stock)**
- **Stock power ( 250 300 hp)** is **outclassed by modern turbocharged or diesel engines**.
- **No turbocharging or supercharging support** (without major modifications).
- **Stock TBI tuning is basic** aftermarket ECU upgrades help but are not as refined as modern systems.
10. **Discontinued Parts & Long-Term Support**
- **Some original parts are no longer made**, requiring **aftermarket or rebuilt components**.
- **Finding a qualified mechanic** who specializes in TBI engines is harder than for modern engines.
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### **Conclusion**
The **1985 GMC/Chevrolet TBI H5 350ci V8** is a **great engine for enthusiasts who enjoy mechanical challenges, modifications, and classic truck power**. It offers **durability, strong towing capability, and extensive aftermarket support** but only if **properly maintained**.
However, for **daily driving, fuel efficiency, or modern compliance**, it is **not ideal**. The **high maintenance requirements, poor emissions performance, and lack of modern technology** make it a **poor choice for most everyday use**.
If you **love working on engines, want a project truck, or need a reliable hauler for off-road/towing**, this engine is **worth considering** but expect **regular upkeep**.
If you **prioritize convenience, fuel economy, or modern features**, a **modern diesel, turbocharged V6/V8, or even a used EFI small-block** would be a **far better investment**.
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### **Recommendation**
- **Buy it if:**- You **enjoy mechanical projects** and don t mind **regular maintenance**.
- You **need a strong, cheap towing/hauling truck** and can **modify it for emissions compliance**.
- You **plan to upgrade it to EFI or a bigger block** (454/466) for better reliability.
- You **find one in excellent condition** with **full service records** (oil changes, valve adjustments, fuel system cleaning).
- **Avoid it if:**- You **want a hassle-free daily driver** with good fuel economy.
- You **live in a state with strict emissions laws** (without a plan to modify it).
- You **don t have mechanical skills or time for repairs**.
- You **prefer modern technology, safety features, or lower insurance costs**.
#### **Best Use Cases:****Project truck** (with plans to rebuild/modify)
**Off-road/towing vehicle** (if properly built)
**Budget-friendly hauler** (if you accept high maintenance)
**Enthusiast restoration** (for classic truck appreciation)
#### **Worst Use Cases:****Daily commuter** (poor MPG, high repair risk)
**Modern emissions-compliant vehicle** (without major modifications)
**Low-budget buyer** (hidden repair costs add up quickly)
**Someone who dislikes mechanical work**
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### **Final Verdict:**The **1985 TBI H5 350ci is a great engine for the right owner** one who **values mechanical skill, enjoys modifications, and doesn t mind trade-offs for raw power and durability**. For everyone else, **modern alternatives are far superior** in
Replaces older part numbers like 17112590. 2 each Used GM GMC Chevy Chevrolet 17113569 throttle body TBI USED - not tested came from closed auto dealer.