Fuel Consumption – General Information |
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The cause of excessive fuel consumption is hard to diagnose and correct because of the potential number of factors involved. Actual fuel consumption problems can be caused by any of the following factors:
Before troubleshooting, it is important to determine the exact complaint. Is the complaint based on whether the problem is real or perceived, or does not meet driver expectations? The Fuel Consumption – Customer Complaint Form (on the next page) is a valuable list of questions that can be used to assist the service technician in determining the cause of the problem. Complete the form before troubleshooting the complaint. The following are some of the factors that must be considered when troubleshooting fuel consumption complaints.
Additional vehicle factors, vehicle specifications, and axle alignment can also affect fuel consumption. For additional information on troubleshooting fuel consumption complaints, refer to Troubleshooting Excessive Fuel Consumption, Bulletin 3387245.
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Fuel Consumption – Customer Complaint Form |
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Customer Name/Company __________________________________________________________ Date ________________ Customer Contact _________________________________________________Customer Phone Number ________________ Describe the issue/complaint in detail, including current fuel economy being achieved: ______________________________________________________________________________________________________ ______________________________________________________________________________________________________ Answer the following questions. Some questions require making an X next to the appropriate answer.
IF AFTER FILLING OUT THIS FORM IT APPEARS THAT THE PROBLEM IS NOT CAUSED BY VEHICLE FACTORS, ENVIRONMENTAL FACTORS, OR DRIVER TECHNIQUE, FILL OUT THE DRIVEABILITY/LOW POWER/EXCESSIVE FUEL CONSUMPTION CHECKLIST.
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Oil Consumption |
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In addition to the information that follows, a service publication is available titled Technical Overview of Oil Consumption, Bulletin 3379214.
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Coolant Loss Pre-Troubleshooting Guide |
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Before troubleshooting, it is critical to know where the coolant is being lost. It is not always obvious where the missing coolant has gone. Before troubleshooting, it is important to determine the exact complaint by interviewing the driver, looking at the service history and looking at the ECM information. Driver Interview QuestionsDriver’s Name: ESN: What is your complaint? How is this engine used? What sort of load factors? Where is the vehicle driven?
Service History ReviewRepeat cylinder head or cylinder head gasket repairs can indicate the problem is likely not the cylinder head or cylinder head gasket. Repeat problems can indicate a deeper problem in the engine. Keep this information in mind while going through the troubleshooting procedure. Look at this engine’s warranty claims history: who worked on the engine last and what did they do? How many miles/kilometers are on this engine? Has a cylinder head or cylinder head gasket been replaced before? At how many miles were the repairs made? ECM Data ReviewPrint out an INSITE™ Image Report from the ECM. Look for high temperature alarms or low coolant level alarms. Either indication confirms a complaint of loosing coolant. Are any fault codes logged in the Engine Protection Fault History?
At this point, do you know where the coolant is going? If not and the coolant loss is not severe, suggest mounting a catch bottle on the radiator overflow tube to catch any overflow that can possibly be blowing out and becoming lost while at speed. Send the vehicle out to collect more data about where the coolant is or is not going. If the catch bottle has some coolant in it, refer back to the Coolant Loss External (out the overflow) interview questions.
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