Adjusting Diesel fuel Injection Timing

Injection Timing Basics

We oftentimes become all kinds of calls asking for technical communication, from both owner-operators trying to troubleshoot a problem with their truck to repair store mechanics who are looking for a second opinion. With all these calls, we discover when multiple questions popular up, pregnant information technology must be a pretty common question. I of the questions that nosotros've gotten a few times is: What is injection timing, and how do I accommodate information technology? If you've found yourself asking that aforementioned question, this article has the nuts that should hopefully give y'all the information y'all're looking for.

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What is Injection Timing

Injection timing is the timing of when fuel is injected into the cylinder, which alters when the combustion takes place. The fourth dimension of when fuel is injected tin can be altered to be injected at dissimilar points in time. The manufacturer of an engine does recommend sure timing, which is the timing they ready it at when the engine is showtime fabricated. This timing is usually balanced to get equally much power as possible, while yet remaining in legal limits for emissions.

Adjusting injection timing is also oft referred to as spill timing.

Why Adjust Injection Timing?

Usually, injection timing is adjusted to create more power in the engine. Timing can be advanced to create more power. Sometimes, timing is adjusted in the opposite direction to fix a smoking or a lag trouble.

Can Injection Timing Be Adjusted On All Diesel fuel Engines?

Young or one-time, timing can be adjusted on any engine. The but difference is how the timing will be adjusted, which is covered after on in this article.

Diesel Engine Injection Timing Adjustments

Advancing

Advancing the timing of an engine means that you are moving the combustion up in time. In other words, you are adjusting the timing so that ignition happens before than when the manufacturer originally set it to occur.

When talking about timing of any kind, just particularly advancing, you'll frequently hear or see the term BTDC, or Earlier Top Dead Center. Top Dead Center, or TDC, for a particular piston is when that piston is at the very top of the cylinder, or furthest from the crankshaft. The opposite, Bottom Dead Eye, or BDC, is when the piston is at its lowest point in the cylinder, closest to the crankshaft. So, BTDC would be the point before the piston is at its uppermost betoken in the engine. A timing advance is the number of degrees BTDC that ignition occurs.

Usually the location is measured in degrees. For example, 10 degrees BTDC is when the crankshaft is 10 degrees before the piston is at its highest bespeak in the cycle. In instance you tin't figure out degrees just past looking at the crankshaft,hither is a handy calculator.

Highway and Heavy Parts | Diesel Engine Timing and Piston Position

Retarding

Retarding the timing of an engine is substantially the opposite of advancing. It is when you adjust timing then that ignition occurs after the manufacturers original specified fourth dimension. People will retard the ignition timing of their engines for various reasons, although it is less mutual. Some of these reasons are fuel economic system and performance.

The rest of this article will focus on advancing the timing of an engine, as that is the almost common timing aligning.

How to Adjust Injection Timing

In that location are several means you tin adjust injection timing, depending on the blazon of engine you have and how old it is. The most common ways to arrange injection timing are programming the ECM, adjusting the fuel injection pump, replacing the camshaft, and replacing the cam followers or gaskets.

Programming the ECM

For newer engines with advanced engine computer systems, adjusting ignition timing is as simple every bit programming the ECM. And past simple, I mean uncomplicated for the people that know how to program them. No mechanical work needs to be done, except for getting to the ECM. From at that place, a mechanic can plug in a Wink tool to reprogram the figurer.

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 yous can manipulate in some way to change the timing.

Fuel Injection Pump

One of the easier means to mechanically conform engine timing is to adjust the fuel injection pump. This is as simple equally 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. Nevertheless, to accurately measure the timing, you will need a special probe or timing meter. Information technology's of import to recall that a pocket-size movement of the pump will result in a large timing change, so do not brand any drastic adjustments. For a tutorial on how to do this yourself, DoItYourself.com haspretty good step-by-step instructionsthat get through the fundamentals.

Camshaft

Another way to accommodate timing is to replace the camshaft. Past replacing your camshaft with one that has differently shaped and sized lobes, you tin can adjust when the valves and injectors are triggered. To practice this, y'all'll probably need to work with a camshaft guru who can do all of the mathematics to get you the cam that will practise what yous want. Cams are most often replaced for timing reasons when being used in performance vehicles.

Cam Followers & Gaskets

A cheaper option for changing when the valves and injectors are triggered is replacing thecamshaft followersor 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 impact when the followers and the cam lobes come into contact, and thus when the rest of the valve train is activated.

Advantages & Disadvantages of Advancing the Timing

Advantages

People advance timing, so there have to be practiced reasons for messing with it, right? Yes. Advancing the timing will ordinarily increment the corporeality of power your engine produces. Information technology will likewise usually increase fuel efficiency. The original engine manufacturers set the timing to balance power and emissions, so that the engines they produce become as much power every bit possible while staying inside legal emissions regulations. This means that they aren't originally prepare to produce the near power that the engine is capable of. And if your engine is older, or it's had some piece of work done, it may simply not exist performing like it used to. Any little thing could affect your timing, so it may just need a flake of an accelerate to upwards the ability.

Disadvantages

However, simply because you tin up the power doesn't hateful that you lot desire to or that you should. This is often a hard lesson for some, simply more than power isn't ever the goal. Advancing the timing tin can atomic number 82 to more fume. Information technology can cause a lot more vibration in the engine, making information technology noisier. It will likewise increase NOx emissions, which is the reason manufacturers ordinarily retard the engines slightly in the first place. And if you don't care nearly any of those things, it volition actually affect the performance of the engine in other ways; advancing the timing will often decrease and delay boost.

A big office of adjusting the timing is doing what's correct 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. Perchance you lot can upwards your power by replacing injectors, and that would exist a better selection for your engine. Perhaps you lot should suit timing. If you do, brand certain you know what you're doing or you hire a mechanic that does.

Highway and Heavy Parts staff have the technical knowledge and experience to help you with your internal engine needs. If y'all have whatsoever outstanding questions about fuel pump timing, or diesel engines in general, please give our ASE Certified Techs a phone call at 844-304-7688. Or, you lot tin can request a quote online.

Originally Posted September xv, 2022; Edited November 11, 2022