John Deere Maintenance Monday: Fuel injection system leak
Radio interview source: Jason Hayes, Product Support Analyst, John Deere
In this edition of Maintenance Monday, we're answering a question from Brett in Oregon. His compact tractor has been difficult to start. When it does start, it's tough to rev up, there's a lot of smoke, and the machine looks like it's leaking fuel. Is there a bad fuel injector?
Possibly, says John Deere Product Support Analyst Jason Hayes. An external leak could be caused by several things. It's common with older, rubber fuel lines that tend to eventually degrade. The injectors may also be loose, or the fuel injection pump is leaking. "If you had a high-pressure fuel leak, if you've got an external injection pump you might notice dust collecting around the fuel lines, which would let you know that you have a small leak, and that's why the dust is collecting to them," Hayes says. "Leaks can also occur from running unapproved fuels. Biodiesel's a good example. A lot of manufacturers have specific recommendation on what kind of concentration. Biodiesel can react negatively with the seals on the fuel line."
It's easy to see drips or dust collecting on an external fuel injector leak, but if the leak is internal, Hayes says your nose will tell you. "You're going to notice the unburnt fuel smell in the exhaust, you're going to have the rough running, you're going to have the smoke issue," he says. "With some of the newer-designed engines, if you have an internal fuel leak internal to the engine, you might notice engine oil and diesel fuel mixing. So when you check your engine oil, you might notice a diesel fuel smell. That's when you know that you have an internal leak."
Have the machine serviced right away to determine where the source of the leak is. Operate the tractor as little as possible, because fuel that touches a hot engine can quickly turn to vapor and be ignited by hot exhaust manifolds or sparks.
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