L5P Injector Connector Failure: Everything You Should be Aware Of
As a 2017 and later owner of GM trucks that have the 6.6L L5P Duramax engine, you might know about one of its more irritating features: injector connector failure. While the L5P offers both reliability and power, concerns have been raised with the wiring harness and connector of the injectors as they can impact vehicle drivability, trigger check engine light alerts, and may even induce misfires or situations where no fuel is injected.
To help you understand this better, in this blog, we will inform you of the reasons behind such failures, what warning signs to look for, and how to repair these issues where possible.
What Causes L5P Injector Connector Failure?
Injector connector failure problems stem from insufficient wire retention along with repetition accompanying movement and vibration within the harness. Failing electrical contacts due to loss of tension, or having intermittent contact in the electrical terminals in injector connectors could be due to:
Vibrational forces stemming from engine rest cycles
Heat cycles induced by the turbo alongside the engine compartment
Connector fitment of poor quality, or locked tab damage
Service associated fitment or unfitment
Due to the harness positioning on the engine and harness routing, cylinder 2 and 7 face greater harness stress and are more susceptible to the ailments described above.
Signs of Problems with Injector Connectors:
The injector connector issues are likely to affect drivability or cause check engine light to appear for some or frequent diagnostic attempts to be undertaken.
These symptoms may include:
Injectors Check Engine Light (CEL) or Service Emission system alerts
Misfires (P0202, P0207, or similar low or high circuit codes)
Inefficient idling or lack of acceleration under pressure
Increased consumption of fuel
Cylinder balancing faults
Short/open DTCs for injector circuits
It is commonly believed that these codes stem from poor intermittent connections at the injector instead of faulty injectors.
Troubleshoot and Diagnose the Problem
The task of diagnosing plug performance is often begun with:
Execution of a wiggle test: During idle, the suspected injector connector is manipulated. Changes in idle are indicative of a problematic injector.
Monitoring the setting of specific diagnosing trouble codes (specific - cylinder related cannot AFS not affecting the cylinder).
Visual examination of the connector - the presence of melted plastic or burnt terminals indicate that the bolts are exposed rather than seated.
Multimeter checks for circuit continuity or resistance.
If the injector is found to be working then the next component of concern becomes the connector and it's plug harness.
Solutions:
There are numerous options available to fix or mitigate potential L5P issues concerning the injector connector:
- Replace the Connector
Connectors get worn from engine vibration over time and need to be replaced. Fleece Performance offers replacement injector connectors with the pigtail.
- Adding a Connector Retention Clip
Some aftermarket companies add locking clips or retention clips that provide extra tension to prevent vibration-induced connector problems. These straps are helpful in solving problems before they arise.
- Replace The Harness
If there are several compromised connectors or if the harness is abraded or saturated with oil, replacing the injector harness segment may provide the most safety.
- Tighten the Harness
Positional re-routing of the harness or using zip ties/loom to anchor the harness can eliminate excess movement which can cause excessive wear over time.
Preventing Issues for a Long Time
Preventing the issue of the injector connector for later servicing involves:
Be careful when dealing with injectors or glow plugs; pulling on the wires is a no-go.
Do not place tools or parts resting over the frame while working on the engine.
If the harness is adjacent to the aftermarket turbo kits or manifolds, heat shielding should be added.
During regular maintenance check and tighten the harness as needed.
Concluding Remarks
Injector connector failure on the L5P Duramax is a chronic problem, but with early detection, it can be rectified before becoming a major issue. If you address the underlying issue with enhanced parts or adjusted paths, it can aid in time, cash and unwanted halting work periods. However, if you are in pursuit of misfire codes or intermittent drivability problems, check the connectors—they might just be the most problematic area in your L5P's fueling system.
