A recent diagnostic report from Indmar has shed light on a concerning issue affecting a Supra Engine, pointing towards fuel contamination as the primary culprit. This analysis details the findings of an inspection conducted on an engine experiencing severe performance problems.
The initial complaint reported by the customer was a critical loss of compression in the #3 cylinder. Upon receiving the unit on August 4, 2021, a thorough inspection was initiated to determine the root cause of this engine malfunction. The event itself reportedly occurred on July 6th, and the engine was taken to the dealer by July 8th. The reason for the delay in Indmar receiving the unit remains unclear.
Visual inspection and subsequent limited teardown of the engine revealed significant damage. Notably, cylinder #3 exhibited zero compression, and the piston in this cylinder was found to be melting and breaking apart. Key operational data indicated that the engine’s registration and sale date was June 26, 2020, with a recorded 121 hours of engine operation.
Further investigation focused on potential mechanical failures and fuel quality. Testing of the #3 injector showed it to be within specified parameters, eliminating it as a potential cause of the piston damage. However, a fuel sample taken directly from the fuel rail provided a crucial clue: visible water contamination was present in the gasoline.
The summary and conclusions of the Indmar report definitively point to fuel contamination as the source of the engine problem. The melted and fractured #3 piston is a direct consequence of the engine running lean, a condition typically caused by excessive water in the fuel and/or the use of low octane fuel. The report explicitly states that damage resulting from unsuitable fuels or lubricants is not covered under the Indmar Limited Product Warranty. Importantly, the inspection found no defects in parts or workmanship that could be attributed to the engine damage, and no other potential causes were identified.
Adding another layer to the issue, the report mentions a misfire alarm recorded at 112 engine hours. Interestingly, while the system logged 6000 alarms, only this single misfire alarm was readily apparent. The customer reported experiencing engine smoking and limp mode during a return trip to the marina for refueling, just before planning another day on the lake. This suggests that the fuel contamination issue may have been developing over time, culminating in the severe engine damage observed.
This case underscores the critical importance of maintaining fuel quality in Supra engines. Water contamination and improper fuel octane levels can lead to significant engine damage, potentially voiding warranty coverage. Regular fuel system checks and adherence to recommended fuel specifications are essential preventative measures for Supra engine owners.
