The Tech Bench
Camry generations fve and six A brief tour of the Toyota Camry fuel and EVAP systems By Jacques Gordon
hood. The fuel rail may have something that looks like a pressure regulator, but it’s Jacques Gordon has worked in the autoactually a pulse damper to reduce presmotive industry for 40 years as a service sure pulsation and fuel pump noise. The technician, lab technician, trainer and mechanical pressure regulator is part of the technical writer. His began his writing career fuel pump module that includes the pump, writing service manuals at Chilton Book Co. a reservoir, the gauge sending unit and a He currently holds ASE Master Technician fuel flter. and L1 certifcations and has participated in The fuel pump module is usually sold ASE test writing workshops. as a complete assembly, but according to the service manual each of those compoince the day it was introduced to the nents can be replaced separately once the U.S. market, the Toyota Camry has module is removed. That includes the only been one of the most reliable cars on fuel flter in the whole system, the strainer the road. With normal maintenance or even or “sock” on the inlet side of the pump. a fair amount of neglect, it seems these cars Turbine pumps are not particularly strong almost never break down. When problems on the suction side, so if there’s a no-start do arise, the diagnosis is rarely a chalor driveability issue that’s caused by lack lenge. But diagnosis is always faster and of fuel, the problem just might be nothing more accurate when you know more about more than a clogged fuel flter. the vehicle. If you don’t normally work Specs for this fuel system are the same on Toyotas, or if you simply haven’t had for all three engines: fuel pressure with the the opportunity to look into a Toyota fuel engine running or not running is 44 to 50 system lately, here’s a quick overview of the psi, hold pressure is 21 psi and fuel injector two most common models. resistance is 11.6 to 12.4 ohms at 68 degrees The 2002-2006 model is the Camry’s Fahrenheit (20 degrees Celsius). ffth generation and the frst year for the There is no fuel pump fow rate specifca2.4-liter 2AZ-FE engine with an electronic tion, and there’s no pressure tap on the fuel mass airfow sensor, electronic throttle and rail either. One way to check fuel volume is a returnless fuel injection system. That to monitor fuel pressure during full-throttle system architecture became the model for acceleration. If fuel pressure falls below Toyota port fuel injected engines right up specifcation during a full-throttle accelerathrough current generation, including the tion, that means the fuel pump can’t keep other engines used in that car, the 3.0-liter up with the demand. 1MZ-FE and the 3.3-liter 3MZ-FE. The fuel injection system’s electrical circuit Returnless fuel systems were developed design is the same on all three engines, to reduce evaporative emissions. The main but it is uniquely Toyota. Power for the difference is the fuel pressure regulator is fuel pump is supplied by what they call the inside the fuel tank instead of under the circuit-opening relay (C/OPN), which any
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22 | July/August 2015
