Troubleshooting Guide for Powerstroke Injectors

mechanics repair diesel injector

Because the Powerstroke injector has many electrical and sensor components that work in harmony, you most definitely require an enhanced functionality diagnostic tool to accurately diagnose any problems. To help you check for common issues and solutions, we’ve developed this quick guide.

First though, it’s important to note that preventive maintenance is very important with diesel engines in general. There are several ways to keep fuel injectors running smoothly, the most common being to add cleaners to fuel. But sometimes you can prevent all you want, and you’ll still encounter issues.

Now get out your diagnostic tool, and let’s get to work with this checklist.

Check Engine: Stalling/Not Starting

If the engine is stalling or it’s difficult to start, you could have a high-pressure oil system leak. If the engine is stalling while warm, it could be on the snap-to-connect fitting on the oil pump —  a frequent problem with Powerstroke injectors.

Check Engine: Jerking

If your engine is jerking or cutting in and out, it could be an issue with the oil pressure or fuel pressure. Test the fuel pressure and run an injector buzz test.

Check the Oil

The Powerstroke needs a high-pressure oil circuit to work properly. Check the oil to ensure you have enough in the system. If you don’t, this could be the cause, and simply filling up the oil could fix your issue.

Verify Fuel Pressure

If fuel pressure is below 45 kpi, the system could be experiencing a plug or a leak. Check for water in the fuel system, as this can easily damage injectors. You may need to drain the tank.

Test Glow Plug System

Especially if you see white smoke, test the glow plug system to see if this is an issue. If it’s a glow plug wiring issue, you may not see it on the diagnostic tool. The glow plugs can be tested by measuring the resistance between each plug circuit at the glow plug control module and the negative battery cable. If no smoke is visible, the glow plug system is not likely the issue.

Check for the injector “buzz”

When doing an injector buzz test, each injector should sound the same; if one sounds different from the others, it may need replacement.

engine parts closeup

Look for Smoke Coming From the Tailpipe

If you notice smoke coming from the tailpipe, it’s likely something is wrong with the combustion.

White smoke means raw fuel is leaving the combustion chamber, meaning there is not enough heat and no auto-ignition is happening. As glow plugs are used to produce the heat necessary to begin the combustion process when the engine starts, white smoke — and, therefore, a lack of heat — means there could very well be an issue with the glow plug system.

If you see gray smoke coming from the tailpipe, this means there is oil burning inside the exhaust. A common cause of this is seal failure on the turbocharger. This is usually accompanied by oil coming from the tailpipe as well. In this case, replacing or fixing the turbocharger is needed.

Black smoke means the fuel is only burning in part — there is likely enough heat for the combustion process, but not enough air. This means there is a problem with airflow, so checking the air filter is a good idea.

Blue smoke means oil is being burned in the combustion chamber, and there could be a leak in the compressor part of the turbocharger.

Test the Cylinder Contribution

To perform the test, select an injector as if you were going to turn it off manually, but do not disable it. You will have approximately one minute to initiate the test — you want to see a straight line in your diagnostic system. If you see the rpm dropping, you need to replace the injector responsible for the drop.

repairman automobile maintenance

Verify FICM Voltage

Lower than 45 volts requires the FICM needing to be replaced. If the voltage reads zero, check the power relay.

Check Clogs in Oil Cooler

If you see coolant blowing out of the degas bottle, the oil cooler is clogged and has likely failed and needs to be replaced.

Engine Takes Long to Start

One of the most common side effects of a cracked line is the diluted oil due to excessive fuel.

A clear sign this is happening is when the engine spins over more than the usual amount when you first start it. This happens because the injection system needs to re-prime itself. A longer crank time usually indicates cracked fuel injectors.

While this is certainly not an exhaustive list of things to check when your Powerstroke injector isn’t working properly, it’s inclusive of the most common issues.

If you continue to have problems, it’s a good idea to take it into the shop.

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