QuestionQUESTION: i drive the vehicle for an hour but everytime when it gets hot when i press the gas pedal there is no reaction. is like the gas is not getting to the injectors i took it to the mechanic and they told me it was the oxygen sensor and the gas filter. when they changed the filter the strainer was really dirty it had wet dirt but the gas was clean they change the filter and the oxygen sensor but it still doing the same thing know theyare telling me is the gas pump that need to be replaced. are they just guessing or could it be a sensor?
ANSWER: There's a very real possibility they are just guessing. For example, an oxygen sensor would typically have nothing to do with these symptoms.
I have seen vehicles with rusting tank and/or filler neck components. When the rust gets into the fuel and subsequently in the fuel pump, it will damage the fuel pump. Typically, if this is the cause, the fuel pump exhibits a high-pitched whining noise. In this case, you'll need not only to replace the pump but also the component that's the source of the rust contamination.
Additionally, I'll suggest that it could be the crank position sensor. These sensors often fail when hot and work normally when cooler.
In the former case, you'll typically experience a gradual lack of power until it's so low the vehicle has trouble running. In the latter, the engine may stumble a few times, but it'll tend to shut off suddenly.
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QUESTION: i took it to a dealer for another diagnostic and they told me that they found a lot of codes. p0134/p154/p0449/p0452/p1167/p0102 and they are saying that i need to replace all this to fix the problem.
ANSWER: I'm going to start with the definitions of the trouble codes. Trouble codes are not things to replace, nor do they necessarily point to things that must be replaced; they give you information about problems which, in many cases, need final diagnosis.
P0102: Reading from air flow sensor too low to be accurate.
P0134: No activity, bank 1, oxygen sensor 1.
P0154: No activity, bank 1, oxygen sensor 2.
P0449: Vacuum indicated by fuel tank pressure sensor when not expected.
P0452: Signal voltage from fuel tank pressure sensor too low to have originated from properly functioning sensor.
P1167: ECM unable to adjust bank 2 fuel mixture enough to achieve proper oxygen sensor reading.
Now I'm going to lump some things together and give you my thoughts about your potential problems.
First, lets put P0102, P0134, P0154, and P1167 together. A scan tool will be necessary to perform proper diagnosis, and the values from the air flow sensor and the fuel trim values (amount of fuel higher or lower than expected amount to achieve proper mixture) will be the data points of prime interest. The current fuel trim values will tell you whether the mixture issue is occurring on both banks or just one. It's possible only one bank crossed the threshold to set the code, but the other bank was near the threshold. If the problem is on both banks, then one should suspect all the above codes may have been caused by a single issue. Is the bellows between the air flow sensor intact, free of leaks, and properly and securely attached? Are there any sizeable vacuum leaks? Are the air flow values normal or low? If low, are the circuits to the air flow sensor intact? A proper diagnosis will include such an inspection. A defective air flow sensor or a sizeable vacuum leak can cause all these codes.
Additionally, I'll not that there's a reprogram for which Hyundai will pay that addresses the P0134 and P0154 trouble codes. It may have already been done, in which case you'd revert back to normal diagnostics for these codes. In this specific case, because P0102 and P1167 are set, diagnostics should start there.
To diagnose the P0452 code, one must check power and ground at the fuel tank pressure sensor and the output of the sensor. In most cases when this code sets, the problem is in the sensor itself, but there could potentially be an issue in the wiring going to the sensor as well. In the event that the fuel tank pressure sensor readings are lower than normal but not so low as to be outside the possible range of readings of the sensor, this can cause the P0449 code to set as well; so addressing the P0452 code may also address the P0449 code.
The issue(s) causing P0449 and P0452 will not cause the vehicle to run poorly.
The issue(s) causing P0102 and P1167 can cause the vehicle to run poorly, so I'd recommend starting with these. It's possible they're unrelated, but you'll never know unless the problem is diagnosed and repaired and the vehicle then redriven.
I'm curious, what exactly are the specific items you've been told need to be replaced?
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QUESTION: they told me to replace the idle air control valve/crankssaft sensor/oxygen sensor/ the throtle body/and air flow sensor you think this is all necessary this sensors are expensive and the labor is crazy
AnswerI find it hard to believe that all of this is necessary, but I also cannot inspect the vehicle.
First I see that they've recommended the crankshaft sensor. This is consistent with a stalling and/or cranks-no start condition. Typically, a problem with the crank sensor will set a trouble code. Since there are no codes relating to the crank sensor, I'm wondering why it was recommended. A common failure mode is that the insulation cracks off the wiring, causing an intermittent short. Perhaps they saw this.
A defective idle control valve can cause a poor idle, stalling at stops or on deceleration, and difficulty starting the car. Once the throttle is depressed (i.e. rpms above idle), there should be no adverse symptoms.
I'm not sure why you'd need to replace the throttle body unless something is very abnormally worn. The throttle body simply consists of a cylinder with a plate mounted to a rod running across the cylinder for the purpose of controlling the amount of air entering the engine. A cable runs between the accelerator pedal and a lever which controls the opening angle of the plate. Also attached to the throttle body is a sensor which measures the amount of plate opening and the idle control valve.
A defective air flow sensor can directly cause some of the diagnostic trouble codes you have (as explained previously) as well as some of your symptoms. This is a plausible repair, but wihtout actually inspecting the car, I'll be unable to determine whether it will address your concerns.
Defective upstream oxygen sensors can cause some of the diagnostic trouble codes (DTCs), also as previously explained, but they will typically cause no symptoms noticeable in the operation of the vehicle.
I'll also note that none of the recommended repairs address the DTCs P0449 and P0452.
