* Lean Air/Fuel Mixture: This is the most common culprit. A lean mixture means there's too much air and not enough fuel. The unburnt fuel doesn't absorb the heat generated by combustion, leading to significantly higher exhaust temperatures. This could be caused by:
* Faulty Fuel Injectors: Clogged or malfunctioning injectors deliver less fuel than needed.
* Faulty Fuel Pump: A weak fuel pump can't supply enough fuel pressure.
* Fuel Pressure Regulator Problems: A malfunctioning regulator could lead to incorrect fuel pressure.
* Air Leaks in the Intake System: Air leaks add extra oxygen to the mixture, making it leaner. Check all vacuum lines and intake manifold gaskets.
* Malfunctioning Mass Air Flow (MAF) Sensor or Throttle Position Sensor (TPS): These sensors regulate the air/fuel mixture; a faulty sensor will lead to incorrect mixture readings.
* Incorrectly Calibrated Fuel Control System (if applicable, depending on the specific Fiero model and modifications): Modifications or incorrect programming can lead to a lean condition.
* Ignition Problems: Incomplete combustion due to weak or improperly timed spark also contributes to higher EGTs. This could be caused by:
* Worn Spark Plugs or Plug Wires: These degrade over time and reduce the effectiveness of the spark.
* Faulty Ignition Coil: A weak coil delivers a weak spark.
* Distributor Issues (if applicable): Problems with the distributor can affect spark timing and delivery.
* Exhaust Restriction: A clogged catalytic converter or severely restricted exhaust system (e.g., from rust or damage) will back up exhaust gases, raising temperatures in the manifold.
* Engine Overheating: While less likely to directly cause the manifold to glow red (the engine would likely be seized first), a severely overheating engine can contribute to higher EGTs. Check coolant levels, radiator condition, thermostat, and water pump.
* Low Coolant: The coolant system helps cool down the exhaust system, and low coolant levels will impact this.
Troubleshooting Steps:
1. Check for obvious exhaust restrictions: Inspect the exhaust system for clogs or damage.
2. Check the engine for overheating: Verify coolant levels and check for any signs of overheating.
3. Check the air/fuel mixture: A proper air/fuel ratio is critical. This often requires a professional mechanic with diagnostic equipment to check for lean conditions. Don't just start replacing parts, diagnosing this accurately requires tools and expertise.
4. Inspect the ignition system: Check spark plug condition, wires, coil, and distributor (if applicable).
5. Check fuel pressure and delivery: This also often requires professional tools and knowledge.
WARNING: Driving a car with a red-hot exhaust manifold is extremely dangerous. The heat can damage surrounding components and pose a significant fire hazard. Stop driving immediately and investigate the cause before attempting to operate the vehicle again. Get it professionally diagnosed and repaired.
