Temperature Variation Instructions - Bosch J 41413-200 Operación Manual

Temperature Variation Instructions

Effects of Temperature on the EVAP Verification Process
The Problem:
Ideal circumstances for conducting the EVAP Flowmeter Test require equal temperatures
between the nitrogen gas and the vehicle's EVAP system. Significant differences in temperature
between them can result in a flow or pressure change during testing, causing misleading results.
Typically, the J 41413-200 Evaporative Emissions System Tester is stored indoors (approximately
70° F). Vehicles brought in for diagnosis may contain EVAP systems at significantly different
temperatures (-40° F to 110° F).
For Example:
When EVAP Flowmeter Tests are performed with significant differences in the nitrogen gas and
the vehicle EVAP system, the following results can occur:
•
An increase in flow during the flowmeter test can be caused by a vehicle's warm EVAP system
cooling down.
•
A decrease in flow during the flowmeter test can be caused by a vehicle's cool EVAP system
warming up.
Note: With no temperature difference between the nitrogen gas and EVAP system, the
resulting vehicle EVAP system pressure will remain stable at 13" H
providing no leaks are present.
The Solution:
When working on a vehicle with significant temperature differences between the vehicle's EVAP
system and the nitrogen gas, use the following guidelines:
Allow the vehicle's EVAP system temperature to stabilize as close as possible to the temperature
of the nitrogen gas before conducting the Verification Flowmeter Test. See the
section in the Operation Manual for more details.
Suggestion: If you are unsure if a temperature difference exists, you can verify the temperature of
the vehicle components and the J 41313-200 by using a non-contact infrared temperature
measurement device such as the J 45842 or J 45844 Infrared Thermometer. Contact
details at 1-800-345-2233.
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Temperature Variation Instructions
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Vehicle Setup
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