Honda 2.5L (152 cu in) firing order — diagram & guide

Over the years, Honda had a few versions of the 2.5-liter engine and the main problem with these is that they feature a different cylinder configuration. Naturally, this made some issues for drivers looking for the best way to maintain these engines, so it’s common to wonder about the Honda 2.5L (152 cu in) firing order.

Because of this, we’ll tell you a few important things about the 2.5-liter engine and discuss some differences in the J25 and G25 versions of it. Of course, we’ll also consider the different firing orders of both, so let’s get into it.

Honda 2.5L J25 firing order

The first 2.5-liter engine we’ll discuss here is the J25 version which is a V6 engine. So, it featured the same firing order as the rest of this engine group. Based on that, the Honda 2.5L J25 firing order is 1-4-2-5-3-6 and it’s completely different from the firing order of the next engine we’ll discuss.

However, there’s a simple trick to use the correct firing order for both of these engines – the J25 has one cylinder more. So, it comes with six cylinders, unlike the G25 which comes with a straight-five configuration, so the firing order will contain one digit less.

Honda 2.5L G25 firing order

The second engine we’ll discuss is Honda’s rare five-cylinder G25 and it’s a completely different engine from the V6. The Honda 2.5L G25 firing order is 1-2-4-5-3, so there’s a clear difference between these two.

Now that you know both of these, you can select the one that’s suitable for your vehicle model and the engine in it. However, to use the firing order, you’ll need to know about the cylinder layout as well, and that’s what we’ll discuss next.

Honda 2.5L cylinder diagram

The cylinder arrangement in a regular Honda 2.5-liter engine is a standard V6 configuration. This is for the J25 engine and there are two engine blocks in this one. The left cylinder bank has cylinder numbers 1, 2, and 3, while the second cylinder bank includes cylinders 4, 5, and 6.

However, when it comes to the G25 engine, there’s a straight-five configuration. This means that the engine cylinders are ordered from 1 to 5 in a straight line. You can find the first cylinder at the front of the engine near the radiator, and the other cylinders follow right up until the fifth one.

Honda 2.5L vehicle applications

To make sure you’ll use the accordant firing order for your car, we’ll give you a list of all the vehicles that use the 2.5-liter Honda engine. So, let’s first start with all the vehicles that are powered by the V6 engine:

• Honda Inspire
• Honda Saber

The five-cylinder engine is only used in the Acura Vigor and the Acura USDM.

Our take

Overall we hope that you will find this guide useful, especially when it comes to deciding which cylinder firing order to use for specific Honda models. So, it’s important to know the difference between the J25 and G25 engines, and we find that to be settled with this guide.