Saturday, December 22, 2012

Diesel Fuel Injector Basics

This is the best video I have ever watched on how diesel fuel injectors work. It covers hole and pintle type injectors that are actuated hydraulically by the high pressure fuel injection system. There are so many different injection systems in the industry it would take a lot of posting to cover them all.

The basics is all you really need to know to get the right idea on how diesel fuel injection systems function. Most Mechanics don't specialize in the fuel injection field primarily since it takes a ton of very expensive testing and calibration equipment to repair injectors and pumps.

 The main principle noted in this video is the injector is seated by a spring. When injection occurs the high pressure fuel is routed to the body gallery of the injector next in the firing order and overcomes spring pressure lifting the seated needle allowing high pressure fuel into the combustion chamber.

When the injection cycle ends the spring in the injector reseats the injector. The mechanic must troubleshoot modern diesel engines with software compared to years ago when you could crack a fuel line one at a time to find an engine miss on a mechanical fuel injection system.

With today's electronic diesel engines a laptop armed with software is the only way to find a problem. Watch the video and you'll get a much better idea through animation how diesel fuel injectors work.


Chad Ralston said...

Hi John,

I've been searching high and low for bus parts supplier names and stumbled across your blog. It appears you really know your stuff, so perhaps you may be able to point me in the right direction.

Basically, I am trying to find the names of vendors that supply crossing arms, relays/switches, etc. to bus manufacturers (such as Blue Bird). I want to ask these vendors more information about how these peripheral devices are connected to the bus itself, i.e. whether it is a simple Input/Output connection or something more complex.

Thanks for any insight or guidance!


Anonymous said...

Mr. Whelan,

I was hoping you might field a question about what kind of buses are the easiest to work on. I'm looking to buy an old bus to use as a camper. I'm only a fair mechanic and I'd like to know if Front Engine, Rear Engine (like in the Thomas and BlueBird Buses) or "Conventional" (like the FreightLiners) would be the easiest to maintain and fix. Also, any things to watch out for when buying such a bus would be greatly appreciated. Many thanks. :)

Thiago daLuz said...

My brother drives a diesel truck. He's going to be getting a new one for work, and a fuel injector would certainly help. Thanks for sharing this, I'll pass it along to him. I'm sure it'll help him decide what kind to go for. Thiago |

John Whelan said...

If you Google "schoolbusparts" you'll find lots of suppliers. I have used they have lots of accessories for school buses.

John Whelan said...

I would look for a conventional school bus with a DT466 International diesel or a Cummins B series. Preferably older and no newer than 2006. The Allison auto trans are very stable as well. Look for auctions for used school district buses.