4runjunkie
New member
Hey guys,
I am hoping the gurus can give me some advice on possible issues to track down that might be causing my horrible gas mileage. I am currently getting about 4km/L, which equals about 8 mpg. I have no stored CEL codes. It has been getting poor gas mileage, not great power output, and slow throttle response since I bought it a year ago (i knew coming in that it was 3vze so I wasnt expecting spectacular mpg's, but this is a little insane). Since then, I have replaced the timing belt, wires, plugs, alternator, water pump, thermostat, dist cap and rotor, and the o2 sensor.
I have read a bunch of threads on these kind of issues, but all of the ones that talk about fuel mileage that is this bad are usually getting a code that gives them an idea of where to start. I know it could be caused by a lot of things, so here is my list so far of things to look into:
-Check Compression
-Check Timing
-Replace Fuel Filter
-Check AFM (All pins within spec when resting. Will take the afm out on the weekend so I can move the vane and check the resistances when the vane is open)
-Check Fuel pressure
-Check Fuel Injectors to see if they are leaking
-Check cold start injector (Seems ok. Resistance is dead on for spec, and no leaking when the fuel pump is on)
-Check CSI time switch sensor (Resistance within spec for warm engine)
-Check ECT (Resistance within spec for estimated engine temp)
-Check to see if the cat is clogged
-Replace exhaust since it is currently very rusted and definitely has some leaks in it
-Check that new O2 sensor is working properly (Resistance between B+ and HT pins measured at 7.0 ohms. According to the fsm that is a little high, but the engine was still warm so I am hoping that when it cools down to the 20 degrees that the fsm asks for, it will fall back into spec)
-Check EGR system (Both tests that I could find for the EGR system have good results: Checked EGR vacuum modulator by plugging ports P and R and blowing into Q, the air flow was as good as expected with such a tiny diameter tube; EGR diaphram checked by applying vacuum to the line that runs into the top of the valve while the engine was running, with vacuum applied the engine wants to stall out)
-Check fan clutch This may be the cause of my issues. The fan starts up as soon as your turn the car on, even if the car is cold. The fan is also hard to spin when the engine is off and cold. I am going to replace this soon and hopefully that will get a bunch more mpg's out of this engine.
My question for you is, is there anything specific you can think of that would cause this bad of gas mileage? Anywhere I should specifically start on that list? Could the leaking exhaust cause that much of a significant drop in mileage? and finally, is there any reason I am not getting a code considering how much fuel is being dumped in with minimal power output?
Thanks for any help you can offer :frog:
I am hoping the gurus can give me some advice on possible issues to track down that might be causing my horrible gas mileage. I am currently getting about 4km/L, which equals about 8 mpg. I have no stored CEL codes. It has been getting poor gas mileage, not great power output, and slow throttle response since I bought it a year ago (i knew coming in that it was 3vze so I wasnt expecting spectacular mpg's, but this is a little insane). Since then, I have replaced the timing belt, wires, plugs, alternator, water pump, thermostat, dist cap and rotor, and the o2 sensor.
I have read a bunch of threads on these kind of issues, but all of the ones that talk about fuel mileage that is this bad are usually getting a code that gives them an idea of where to start. I know it could be caused by a lot of things, so here is my list so far of things to look into:
-Check Compression
-Check Timing
-Replace Fuel Filter
-Check AFM (All pins within spec when resting. Will take the afm out on the weekend so I can move the vane and check the resistances when the vane is open)
-Check Fuel pressure
-Check Fuel Injectors to see if they are leaking
-Check cold start injector (Seems ok. Resistance is dead on for spec, and no leaking when the fuel pump is on)
-Check CSI time switch sensor (Resistance within spec for warm engine)
-Check ECT (Resistance within spec for estimated engine temp)
-Check to see if the cat is clogged
-Replace exhaust since it is currently very rusted and definitely has some leaks in it
-Check that new O2 sensor is working properly (Resistance between B+ and HT pins measured at 7.0 ohms. According to the fsm that is a little high, but the engine was still warm so I am hoping that when it cools down to the 20 degrees that the fsm asks for, it will fall back into spec)
-Check EGR system (Both tests that I could find for the EGR system have good results: Checked EGR vacuum modulator by plugging ports P and R and blowing into Q, the air flow was as good as expected with such a tiny diameter tube; EGR diaphram checked by applying vacuum to the line that runs into the top of the valve while the engine was running, with vacuum applied the engine wants to stall out)
-Check fan clutch This may be the cause of my issues. The fan starts up as soon as your turn the car on, even if the car is cold. The fan is also hard to spin when the engine is off and cold. I am going to replace this soon and hopefully that will get a bunch more mpg's out of this engine.
My question for you is, is there anything specific you can think of that would cause this bad of gas mileage? Anywhere I should specifically start on that list? Could the leaking exhaust cause that much of a significant drop in mileage? and finally, is there any reason I am not getting a code considering how much fuel is being dumped in with minimal power output?
Thanks for any help you can offer :frog:
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