Pulling Injectors, Checking O-Rings

December 2018 Ask The Expert, Feature

            (EDITOR’S NOTE: Since watching others work is common practice for the editors of Diesel Tech Magazine, this section is dedicated to all the diesel technicians whose work is interrupted by someone looking over their shoulders and asking annoying questions.)

            We decided to stop by PowerTech Diesel in Idaho Falls, ID, and ask EJ Wyatt, “Whatcha working on?” With somewhat of a mixed look of bewilderment and annoyance, Wyatt glanced around the shop and said, “these four trucks.” Not wanting to invest that much time, we picked out one of them, the Ford F-350 Super Duty.

DT—What’s going on here?

Wyatt—I’m working on a ’02 7.3L Has a high pressure oil leak. Not making oil pressure on the ICP. So I’m pulling out injectors and checking O-rings, making sure the O-rings are good. Then after that I’ll just go through some other little things. The truck had a hard start or no start condition so we are checking the injectors.

DT—Explain what you need to do?

Wyatt—First, you take the intake off on the driver’s side. Pull the intercooler pipe out, the valve cover, harness for the injectors and glow plugs. Then you have your four oil returns that bolt to your injector that return the oil down instead of out. Then you have these 8mm bolts. Remove them and pull it out.

DT—What are you looking for on the injectors?

Wyatt—So far these four injectors look good. These O-rings are what they are supposed to look like. I just look to see if they have gouges or cuts or are flat where they won’t make a seal. If so then you pull them off and get a re-build kit and put new O-rings for them. So I’m going to start on the next side.

DT—What do you try to avoid or make certain you don’t forget?

Wyatt—If you’re not careful and fail to lube up your O-rings before you re-install them, you can tear them when you re-install the injectors and have the same problem. You want to make sure they are completely lubed up and they will then slide right in. Also, on this engine you want to make certain you drain your oil rail before you pull the injectors out. You can fill the whole cylinder with oil and then it will hydro lock and it won’t start. And then you will have to take it all apart, pull the glow plugs out and crank it until all the oil is out.

DT—How long does it usually take to complete this job?

Wyatt—Start to finish, it’s a four-hour process depending on what goes wrong and what doesn’t go wrong. And if done right, the truck is going to start easy and not give the owner any more fits.

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