The Detroit Diesel Series 60 engine is known for its reliability, but like any complex system, it can experience issues. One common problem involves the fuel check valve, a critical component in the fuel return system. This article will explore the symptoms of a faulty Detroit 60 series fuel check valve, share a real-world troubleshooting experience, and clarify its often-misunderstood location.
Understanding the Detroit 60 Fuel System and Check Valve Function
The Series 60 fuel system operates on a loop principle. Fuel travels from the tank to the filter, then to a mechanically driven fuel pump. The pump delivers high-pressure fuel to the engine head, where it circulates and powers the injectors. Excess fuel returns to the tank via a return line.
The fuel check valve, located in the return line, prevents fuel from siphoning back from the engine head into the tank when the engine is off. This ensures the fuel system remains primed for a quick start. A malfunctioning check valve can lead to hard starting or no-start conditions. Contrary to many manuals and online resources, the check valve on a Newell coach with a Detroit 60 is not at the back of the engine. It’s positioned in the return line just before it enters the fuel tank – a crucial detail for troubleshooting.
Symptoms of a Faulty Detroit 60 Fuel Check Valve
While a failed check valve is a prime suspect for hard starting, it rarely presents in isolation. Here are some common symptoms that might indicate a faulty check valve:
- Hard Starting or No Start: The engine cranks but struggles to fire or doesn’t start at all, often after sitting overnight. This is due to loss of prime in the fuel system.
- Fuel Level Fluctuations in the Filter Housing: You might observe a higher fuel level in the filter housing after the engine has been off for a period, indicating fuel draining back from the engine.
- Air in the Fuel System: A faulty check valve can allow air to enter the return line, causing further starting problems. While not a direct symptom of check valve failure, air intrusion can exacerbate the issue.
A Real-World Troubleshooting Case Study: The Vacuum Tank Mystery
A recent troubleshooting experience highlighted the importance of understanding the entire fuel system. A Detroit 60-powered coach experienced a no-start condition. Initial checks revealed no fault codes and adequate fuel in the filter housing. After several attempts, the engine finally started and ran without further issues for a considerable distance. Suspicion fell on a loss of prime, possibly due to a failed check valve.
Further investigation revealed a surprising culprit. The fuel tank was found to be under significant vacuum, evidenced by a loud “bong” upon removing the fuel cap. This vacuum was strong enough to draw fuel back from the engine, mimicking a failed check valve. The root cause? A pinched vent line preventing the tank from breathing properly. Replacing the vent line resolved the issue.
This experience underscores the importance of systematic troubleshooting. While the check valve was initially suspected, a thorough inspection revealed a different problem with similar symptoms. Always consider all possibilities before concluding a component failure. In this case, the check valve was actually located near the fuel tank, simplifying potential replacement.
Conclusion: Thinking Beyond the Obvious
Troubleshooting a Detroit 60 fuel system requires a comprehensive understanding of its components and their interactions. While a faulty fuel check valve is a common cause of hard starting, it’s crucial to consider other potential issues, like a restricted vent line. Remember, the check valve on Newell coaches equipped with a Detroit 60 is typically located near the fuel tank, not the engine’s rear. Always perform a thorough inspection and think beyond the obvious when diagnosing starting problems. Sometimes, the simplest solution is the correct one.
