As a diesel owner, you know that proper fuel injection timing is crucial for the smooth operation of an engine. Incorrect injection timing can lead to issues such as poor fuel economy, reduced power, and increased emissions.
In this blog post, we will explain the basics of diesel injection timing and how to adjust it.
What is Diesel Injection Timing?
Diesel injection timing refers to the point at which fuel is injected into the engine’s combustion chamber. In a diesel engine, fuel is injected directly into the cylinder, rather than into the intake manifold as in a gasoline engine. The timing of the injection is controlled by the engine’s computer, which uses input from various sensors to determine the optimal time to inject fuel.
Why is Diesel Injection Timing Important?
Proper diesel injection timing is essential for several reasons. First and foremost, it affects the engine’s performance. If the fuel is injected too early or too late, it can result in reduced power and fuel efficiency. Additionally, incorrect injection timing can cause excess emissions, which can have negative environmental impacts.
CAN INJECTION TIMING BE ADJUSTED ON ANY DIESEL ENGINE?
Of course! No matter how old, or new your diesel engine is, an injection pump will always be there. Old school guys took pride in being able to adjust the timing by hand with a couple of common hand tools everyone had sitting around.
Unfortunately nowadays, not much can be done on a vehicle without at least having basic computer skills. Technology is advancing at a rapid pace, and the once-simple diesel engine has been equipped with a series of computers that control everything from injection timing to the cab temperature. Injection timing can still be adjusted on a modern truck, but now it is done via the ECM.
ADVANCING AND RETARDING ENGINE TIMING
There are two main ways to adjust your injection pump timing. This can be done by advancing or retarding the actual point of when the fuel enters the combustion chamber.
ADVANCING
Advancing the timing means that you are changing when the combustion process will take place in relation to the piston’s position.
By advancing the injection timing, the combustion process will take place before the manufacturer initially intended it to. Doing this should increase horsepower. But like with anything, there are downsides to advancing the timing as well.
Added smoke will be the main visual cue that someone has advanced the timing on a diesel engine. What you might not know is that emissions have a chance to be greatly increased as well by advancing injection timing.
A delicate balancing act must be played by environmentalists and the engine manufacturers. Automakers and enthusiasts alike want to make as much power as possible from their diesel workhorses, while on the other end, strict pollution regulations must be followed. It is a subject that both sides butt heads on regularly.
ENGINE TIMING RETARDING
Retarding the timing, on the other hand, does the exact opposite of advancing. In other words, fuel will be delivered after the manufacturer intended it to.
You will rarely hear of people retarding their timing, mainly because this is one of the best ways to reduce horsepower output. However, if done right, it could help increase fuel efficiency. Since it isn’t a common procedure, we won’t go into further detail about retarding injection timing.
How to Adjust Diesel Injection Timing:
There are several ways you can adjust injection timing, depending on the type of engine you have and how old it is. The most common ways to adjust injection timing are programming the ECM, adjusting the fuel injection pump, replacing the camshaft, and replacing the cam followers or gaskets.
OPTION 1: PROGRAMMING THE ECM
For newer engines with advanced engine computer systems, adjusting ignition timing is as simple as programming the ECM. And by simple, I mean simple for the people that know how to program them. No mechanical work needs to be done, except for getting to the ECM. From there, a mechanic can plug in a Flash tool to reprogram the computer.
Need a new ECM? Check out some of the ECMs that Highway and Heavy Parts offers.
For older, mechanical engines, there are still several parts that you can manipulate in some way to change the timing.
OPTION 2: ADJUSTING THE FUEL INJECTION PUMP
One of the easier ways to mechanically adjust engine timing is to adjust the fuel injection pump. This is as simple as rotating the pump in the engine. Rotating the pump requires just a screwdriver and a socket wrench, which most people have in their toolboxes at home. However, to accurately measure the timing, you will need a special probe or timing meter. It’s important to remember that a small movement of the pump will result in a large timing change, so do not make any drastic adjustments. For a tutorial on how to do this yourself, DoItYourself.com has pretty good step-by-step instructions that go through the fundamentals.
OPTION 3: CAMSHAFT REPLACEMENT
Another way to adjust timing is to replace the camshaft. By replacing your camshaft with one that has differently shaped and sized lobes, you can adjust when the valves and injectors are triggered. To do this, you’ll probably need to work with a camshaft guru who can do all of the mathematics to get you the cam that will do what you want. Cams are most often replaced for timing reasons when being used in performance vehicles.
OPTION 4: REPLACING CAM FOLLOWERS & GASKETS
A cheaper option for changing when the valves and injectors are triggered is replacing the camshaft followers or gaskets. These can do the same, or very similar, things that replacing the camshaft would do. For example, switching out the cam follower gaskets for thicker or thinner ones would affect when the followers and the cam lobes come into contact, and thus when the rest of the valve train is activated.
Advantages and Disadvantages of Advancing Injection Timing:
Advantages:
People advance timing, so there have to be good reasons for messing with it, right? Yes. Advancing the timing will usually increase the amount of power your engine produces. It will also usually increase fuel efficiency. The original engine manufacturers set the timing to balance power and emissions, so that the engines they produce get as much power as possible while staying within legal emissions regulations. This means that they aren’t originally set to produce the most power that the engine is capable of. And if your engine is older, or it’s had some work done, it may just not be performing like it used to. Any little thing could affect your timing, so it may just need a bit of an advance to up the power.
- Increases engine power
- Increases fuel efficiency
- Can help improve engine performance in certain cases
Disadvantages:
However, just because you can up the power doesn’t mean that you want to or that you should. This is often a hard lesson for some, but more power isn’t always the goal. Advancing the timing can lead to more smoke. It can cause a lot more vibration in the engine, making it noisier. It will also increase NOx emissions, which is the reason manufacturers usually retard the engines slightly in the first place. And if you don’t care about any of those things, it will actually affect the performance of the engine in other ways; advancing the timing will often decrease and delay boost.
A big part of adjusting the timing is doing what’s right for your engine, and if you do it, doing it right. If you’re considering adjusting the timing, take the time to figure out what your engine needs. Maybe you can up your power by replacing injectors, and that would be a better option for your engine. Maybe you should adjust the timing. If you do, make sure you know what you’re doing or you hire a mechanic that does.
- Increases smoke and NOx emissions
- Increases vibration and noise in the engine
- Can decrease and delay boost
- Can affect engine performance negatively if not done correctly
Conclusion:
Injection timing is important for the engine’s performance, fuel efficiency, and emissions. There are several ways to adjust it, including programming the engine control module, adjusting the fuel injection pump, replacing the camshaft, or replacing the cam followers or gaskets. Adjusting the timing can affect power, fuel efficiency, and emissions, and it is important to consult with a mechanic or refer to the manufacturer’s guidelines before making any changes.
Highway and Heavy Parts staff have the technical knowledge and experience to help you with your internal engine needs. If you have any outstanding questions about fuel pump timing or diesel engines in general, please give our ASE Certified Techs a call at 844-304-7688 or simply request a quote online!
Related Articles:
DIESEL ENGINE FUEL INJECTORS EXPLAINED
DIESEL ENGINE INJECTOR REPAIR KITS AND REMANNED INJECTORS
ADJUSTING DIESEL INJECTOR TIMING: ISX INJECTORS
CHOOSING THE RIGHT DIESEL ENGINE COMMON RAIL FUEL INJECTORS
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