Mustang Fox Body Engine Bay Diagram
Last Updated May 8, 2024 | Nate MoonisAs the Mustang generations progressed, their engine bays became more and more complex. The Fox Body Mustang has a ton of technology packed under the hood, so there is a lot to remember.
The Fox Body Mustang has become a fan-favorite among enthusiasts and tuners alike. If you want to work on your Fox Body's engine, look no further than our in-depth engine diagrams with definitions for each labeled part. Reference this guide the next time you're working on your Fox.
Fox Body Engine Diagrams
| 1. | Upper Intake Plenum - One of the first things people see in your engine bay, the upper intake plenum creates a high-pressure area to allow for maximum performance. Swap the stock upper intake plenum out to improve performance and the look of your engine bay. |
| 2. | Electronic Distributor - The electronic distributor sends high-voltage current from the ignition coil to the spark plugs in sequence to deliver the spark needed to ignite the air/fuel mixture. |
| 3. | Mass Air Flow Sensor - This sensor is mounted to the inside of your intake tubing and is used to measure the amount of air passing through the tube into the engine. The sensor sends that information to the ECU so it can determine the correct air/fuel ratio for the best performance. |
| 4. | Air Cleaner Housing - This black box sits in the bottom left of your engine bay and contains the air filter. It filters out any debris in the intake air before it gets sent into the engine. |
| 5. | Alternator - The alternator charges the battery while your car is running. This supplies your onboard electronics with the electricity they need to function. It's essentially a generator that generates charge by getting spun by the serpentine belt. |
| 6. | Belt Tensioner - The belt tensioner in your Fox Body Mustang mounts to the front of your engine and keeps the tension throughout the serpentine belt path. It has an arm and a free-spinning pulley that creates tension on the serpentine belt and stops it from becoming loose or slipping. |
| 7. | Coolant Reservoir - The coolant reservoir captures excess coolant that has expanded due to the heat and been pushed out of the system. It cycles that coolant back into the radiator as it cools down. |
| 8. | Radiator Cap - This small cap seals the top of the radiator filler neck while also pressurizing the coolant system and increasing the boiling point of your coolant. You can opt for an aftermarket radiator cap to add a splash of chrome to your engine bay. |
| 9. | Battery - One of the most important parts in your engine bay, the battery provides your engine with the electricity it needs to function. It gets charged by the alternator while you drive. With a dead car battery, you won't even be able to start your Fox Body. |
| 10. | Power Steering Pump - The power steering pump pressurizes and distributes the hydraulic fluid that allows you to turn the wheel with ease. |
| 11. | Air Conditioning Compressor - While not essential to the function of your engine, it pushes refrigerant through your A/C system to keep your interior cool during hot days. |
| 12. | Brake Master Cylinder & Booster - These two components work in tandem to distribute brake fluid to each caliper/drum through the use of vacuum. Without a functioning brake master cylinder and booster, your brakes would be incredibly hard to use effectively. |
| 13. | Windshield Wiper Motor - This small motor mounted to the firewall on the back of your engine bay powers your windshield wipers and allows them to work smoothly. Over time, the plastic cover on it can be lost or broken. |
| 14. | Hood Ground Strap - This strap connects your hood to the chassis and provides a reliable ground for your electrical system. Without it, your Fox Body's electrical system wouldn't function. |
| 15. | 10-Pin Connector - These connectors are the main engine-to-body wiring harness connection. They're commonly known by Fox Body enthusiasts as salt and pepper shakers and often fail over time. |
| 16. | EGR Spacer - This small but essential part helps to recirculate your exhaust gases while providing a mounting point for your throttle cable. |
| 17. | EGR Vacuum Regulator Solenoid - The EGR vacuum regulator solenoid is controlled by the PCM and controls the vacuum that opens the EGR valve. |
| 18. | Idle Air Bypass Valve - The idle air bypass valve regulates the amount of air needed to maintain a smooth idle. |
| 19. | Thermactor Air Diverter Solenoid - The thermactor air diverter solenoid directs thermactor air from the rear of the cylinder heads to the exhaust after warm-up. |
| 20. | Air Inlet Hose - The air inlet hose directs air into the throttle body from the mass air flow meter (Mass air car) or the air box (Speed Density Car). |
| 21. | Mass Air Flow Meter - The mass air flow meter measures the amount of air entering the engine and reports the information back to the ECU. |
| 22. | Oil Filler Cap - This seals the top of the oil filler neck. |
| 23. | Radiator - This essential component cools hot coolant that has traveled through your engine. It's mounted at the front of your engine bay to cool the coolant using the air that comes through the front grille. |
| 24. | Spout Check Connector - The spout check connector completes the circuit to the distributor and allows the PCM to have timing control. This needs to be removed if you're trying to adjust or set your engine timing. |
| 25. | Engine Coolant Temperature Sensor - The engine coolant temperature sensor does exactly what its name implies, it sends the temperature of the coolant to the ECU. This allows the ECU to adjust the air/fuel ratio, ignition timing, and EGR flow accordingly. |
| 26. | Injectors - The fuel injectors atomize fuel and inject it directly into the combustion chamber to allow for combustion to occur. Without fuel injectors, your car would not be able to run. |
| 27. | Water Pump, Fan & Fan Clutch - These are all components that help cool and move engine coolant throughout your engine. |
| 28. | Center Line Crash Sensor - Only found in 1990-1993 Fox Body's, the center line crash sensor triggers the airbag in the event of a front-end collision. |
| 29. | Power Steering Fluid Resevoir - This holds the power steering fluid that powers the power steering system in your Fox Body Mustang. |
| 30. | Ignition Coil - This important component provides your distributor with the voltage it needs to transfer electricity to the spark plugs. It can be hard to locate because it's under a plastic cover. |
| 31. | Vacuum Hose Diagram - A handy diagram that shows you how the vacuum hoses in the engine are routed. |
| 32. | Starter Relay - Also known as the starter solenoid. The starter relay completes or breaks the electrical circuit to the starter to turn it on or off and start your car. |
| 33. | Engine Oil Dipstick - This long, thin metal component goes directly into your oil pan and allows you to measure your oil levels easily. It has markings on it that indicate what an acceptable oil level is. |
| 34. | Front Strut Insulator & Camber Adjustment Plate - The front strut insulator and camber adjustment plate rest on top of the strut and strut tower and are used in dampening and adjusting your suspension. |
| 35. | VIP Test Connectors - Also referred to as the EEC/OB1 tester, this connector allows you to hook up the Ford Star tester tool to your Mustang to read codes. |
| 36. | Barometer Absolute Pressure Sensor - Otherwise known as the BAP sensor, the barometer absolute pressure sensor measure barometric air pressure and reports it to the ECU. |
| 37. | EGR Valve & EGR Position Sensor - The EGR valve allows exhaust gases to enter the intake passage during various engine speeds. The EGR position sensor reports valve position to the ECU. |
| 38. | Crankcase Ventilation Tube - The crankcase ventilation tube allows excess gases to escape the crankcase in a controlled manner. |
| 39. | Vacuum Distribution Tree - The vacuum distribution tree channels vacuum to every component in your engine that requires vacuum. From left to right, the connections are vacuum source (intake manifold), unused, vacuum reservoir, speed control servo (if equipped with cruise), and power brake booster. |
| 40. | Wiring Harness - The wiring harness connects all of the engine's electrical components to the computer in the passenger side kick panel. There are several wiring harness differences depending on your Fox Body Mustang's model year. |
| 41. | Thermactor Air Bypass Solenoid - Commonly abbreviated to TAB, the thermactor air bypass solenoid vents thermactor air during periods when it is not needed (primarily cold starts). |
| 42. | Vacuum Storage Canister - This stores vacuum to prevent an interruption at full throttle. |
| 43. | WOT Cutout Relay - This relay turns the AC compressor clutch off when at full throttle. |
| 44. | Fuel Pump Relay - The ECU sends a signal to your fuel pump through this relay to tell it to turn on when your ignition is turned on. |
| 45. | Canister Purge Solenoid - This allows fuel vapors from the carbon canister to enter the intake manifold. |
| 46. | Air Silencer - This is located in the fender and is used to muffle incoming air noise. |
| 47. | Air Conditioner Condenser Connections - These attach the refrigerant lines to the AC condenser. |
| 48. | AC Accumulator - The AC accumulator provides a storage area for the refrigerant in the AC system and houses a chemical drier that removes moisture from the refrigerant. |
| 49. | Thermactor Bypass Valve - This valve directs air into the atmosphere when none is needed. |
| 50. | Throttle Body - This regulates the amount of air entering the engine and is controlled by the gas pedal. When you accelerate, the throttle body allows more air to enter the engine. |
| 51. | Thermactor Air Pump - The thermactor air pump delivers high volume, low pressure fresh air to the exhaust system. |
| 52. | EGR Coolant Hoses - Circulates coolant through the EGR spacer. |
| 53. | Throttle Position Sensor - Relays the percentage of throttle opening to the computer. |
| 54. | AC Low Pressure Switch - The AC low pressure switch observes the pressure of the AC system and will not allow the air conditioner compressor clutch to energize if refrigerant pressure drops to an unsafe limit. |
| 55. | Vacuum Check Valve - The vacuum check valve allows air to flow in only one direction to keep the vacuum storage canister fully charged. |
| 56. | Fuel Pressure Regulator - The fuel pressure regulator controls fuel pressure and ensures your engine gets the correct amount of fuel throughout the RPM range. |
| 57. | Positive Crankcase Ventilation Valve - Often referred to as the PCV valve, the positive crankcase ventilation valve relieves crankcase pressure. |
| 58. | Air Charge Temperature Sensor - This sensor reports the temperature of the air in the intake manifold to the ECU. |
Find the Part or Component You're Looking For with Ease
If you're struggling to find something in your engine bay during your next project, be sure to check back on these diagrams to find the component you're looking for. These diagrams are also a great learning resource for those looking to become more knowledgeable about their Fox Body.
This article was researched, written, edited, and reviewed following the steps outlined in our editorial process. Learn more about our editorial standards and guidelines.
