3.5 Ecoboost Firing Order [With Diagram]

The combination of power and fuel efficiency of Ford’s EcoBoost engine technology has made it widely popular. To truly comprehend the inner workings of these engines, it’s essential to understand the concepts of firing order and cylinder layout. In this article, we will go into the details of the firing order and cylinder layout, as well as explore common misfire issues that may arise.

Firing order for 3.5 EcoBoost

  • The firing order for 3.5 Ecoboost is 1-4-2-5-3-6

Explanation of 3.5 EcoBoost firing order

The firing order for 3.5L Ecoboost engine is 1-4-2-5-3-6.To understand the firing order, we first need to visualize the cylinder arrangement in the engine. As the name shows, it has 6 cylinders that are arranged in a V shape. In this configuration, there are three cylinders on each side of the V.

The firing order starts with cylinder number 1, which is located on one side of the V. After cylinder 1 fire, the firing order moves to cylinder 6, which is located on the opposite side of the V. This alternating pattern continues with cylinder 5, which is on the same side as cylinder 1, and then cylinder 10, which is on the opposite side.

The firing order is carefully designed to optimize the engine’s performance and balance. It ensures that each cylinder fires in a specific sequence, minimizing vibration and maximizing power delivery.

The firing order applies to

  • Ford 289
  • Ford 390
  • Ford 427

Torque specifications

Main Cap Bolts60-70 ft.-lbs.
Connecting Rod Bolts22-25 ft.-lbs. (40-45 ft.-lbs. for 289TP and Boss 302)
Cylinder Head Bolts65-72 ft.-lbs.
Rocker Arms17-23 ft.-lbs.
Intake Manifold Bolts23-25 ft.-lbs.
Oil Pump Bolt23-28 ft.-lbs.
Cam Bolts40-45 ft.-lbs.
Cam Thrust Plate Bolts8-10 ft.-lbs.
Harmonic Damper Bolt70-90 ft.-lbs.

Misfires in the 3.5 EcoBoost Engine

Engine misfires can occur when the air-fuel mixture fails to ignite in the intended cylinder. The 3.5 EcoBoost engine is not exempt from misfire issues, and two cylinders, in particular, have been prone to misfires: cylinder 5 and cylinder 6.

Misfire in Cylinder 5

Cylinder 5 misfires can stem from various causes, such as a faulty spark plug, fuel injector problems, ignition coil issues, or even a vacuum leak. When a misfire occurs in cylinder 5, it can lead to reduced engine performance, rough idling, and decreased fuel efficiency. Timely diagnosis and appropriate troubleshooting techniques are essential to rectify the issue and restore optimal engine operation.

Misfire in Cylinder 6

Cylinder 6 misfires can also present challenges for 3.5 EcoBoost engine owners. Identifying the occurrence of a misfire in this cylinder involves recognizing symptoms like engine vibration, loss of power, or a noticeable decrease in fuel economy. Potential causes can include issues with the spark plug, fuel delivery, or ignition system components. Professional diagnosis and necessary repairs are necessary to resolve cylinder 6 misfire concerns.

Check out Hemi Firing Order

Firing orders for similar vehicles

  • Ford FE engine 352/360/390/406/410/427/428 1-5-4-2-6-3-7-8
  • Ford 385 series 1-5-4-2-6-3-7-8
  • Big Block 429/460 1-5-4-2-6-3-7-8

How are the cylinders numbered on the Ford 3.5 EcoBoost engine?

On the Ford 3.5 EcoBoost engine, the cylinders are numbered sequentially from the front of the engine to the back. A driver’s seat view shows that the left bank of cylinders has several 1-3-5 and the right bank has several 2-4-6.

Where is Cylinder 2 located in the Ford 3.5 EcoBoost engine?

Cylinder 2 on the Ford 3.5 EcoBoost engine is located on the right bank of cylinders.

Where is Cylinder 4 located in the Ford F150 3.5 EcoBoost engine?

Cylinder 4 on the Ford F150 3.5 EcoBoost engine is located on the left bank of cylinders when viewed from the driver’s seat.

How many cylinders does the 3.5 EcoBoost engine have?

It has six cylinders, which makes it a V6 engine.

Jake Mayock