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Diesel no starts: the new rules

Tuesday, March 1, 2016 - 08:00
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If DTCs related to those systems are present, taking a few minutes to record and investigate them is smart since they’re probably related to the no-start condition. And since a surprisingly large number of no-start conditions are fixed by reprogramming a module, it’s also wise to check for calibration in the modules’ updates early on. This can and does save time and headaches.

Additionally, it’s a good idea to watch what’s actually happening to the critical inputs on the scan tool before and during cranking, checking for not only the presence and value of the critical parameters (to make sure the engine has the correct parameters to start and run) but also to note any that disappear or change drastically or disappear during cranking. Service information will list the critical ones along with expected values, which can save hours of time later on. From experience, a problem in the electrical system tends to fail suddenly rather than develop slowly and get worse so if the problem developed suddenly, pay extra attention when observing the reading (especially if you noticed oil-soaked harnesses or leaks earlier on).

Again, following service information is important, but it’s also important to understand what you’re looking for and why so you don’t waste time or miss the obvious symptoms.

Glow plugs

As much as diesel systems have changed and evolved, faulty glow plugs are still a common problem that causes no-start conditions. But fortunately, on newer vehicles the systems can set trouble codes to indicate problems and save diagnostic time.

If the no-start problem occurs when the vehicle is cold or if the vehicle has been getting harder to start when it’s cold, checking the glow plugs early on in the diagnosis is a good idea. The Ford dealer tech mentioned earlier quickly checks glow plug values (resistance and amperage draw) during regular services to catch them and replace them before they cause a no-start condition.

Removing and actually inspecting the air filter to check for restrictions is more accurate than just looking at the gauge on the air filter housing.
The filter element, removed
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