QuestionQUESTION: Good day experts, This is for a 2000 Hyundai Accent GS.
I replaced my ECU due to a shorting fuse while it was in storage(been on the military I had it in storage).
After the repair and get it shipped to Puerto Rico I noticed various symptons. The symptons didnt show up until months later. They started small and almost no vibration and now it is annoying, mid-loud, noticeable vibrations. I also have an intake with a new K&N air filter installed. Will clean it today just in case.
The symptons are as follows:
When the car is in idle, its RPM is low (~800-850 RPM). It trembles. When I turn on my A/C it trembles more when in idle. You dont feel this trembling when driving, so i guess it is related to the low RPM.
I got an engine light on now, tried resetting the light by unplugging the battery and replugging it, it when away and came back while driving and stays.
After scanning it got the codes:
P1128 - manufactured controlled fule and air metering
P0133B - O2 sensor B1S1 Slow response
An airconditioner mechanic told me to try and raise the rpm to eliminate the problem. He is also telling me it is all related to a bad computer, to replace it.
I am not sure if it is the computer or a bad O2 sensor, so I wanted to ask some experts to give me some input. I am also worried that raising the RPM manually may cause other problems.
Other people say it is the intake that is too much for a small engine.
ANSWER: P1128 indicates that the ECM perceives a lean mixture. Since you've installed an aftermarket intake start there. It's imperative that there are no leaks between the air flow sensor and throttle body. If there are, it'll cause the P1128 trouble code and your engine may run poorly. Second, I recommend not using an oiled filter. This can damage the air flow sensor, causing the P1128 and your current problems. You should also check for any vacuum leaks, especially at the PCV hose. If you find no vacuum or intake leaks, you probably need to replace the air flow sensor.
P0133 is likely unrelated to your vibration issue. First, check for exhaust leaks. If you have any leaks, repair them. Most frequently, there is a leak in the flexible portion of the front pipe. Even a very small leak there can cause this trouble code. If you have no exhaust leaks, replace the front oxygen sensor.
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QUESTION: Thanks for the information, related to the same car. I also noticed after the change of computer that the fuel gauge reads wrong all the time. Basically the gauge goes from full to empty, but sometimes I counts 6 gallons as a full tank, other times it count 8 as a full tank. The thing is that this tank is made to hold 12 gallons (thinking 2 for reserve). Also this car used to run 320 highway, 270 city on a full gas tank, now it runs about 120-180 per gallon.
AnswerYour fuel gauge works off the resistance of the fuel level sender (float) in the fuel tank. Since this circuit isn't controlled by your computer, the problem here cannot be related to the computer replacement.
It sounds like your fuel gauge is reading empty when the tank is not actually empty. Most frequently, the problem is with the fuel level sender, but it can also be with the fuel gauge or the wiring. To check the gauge and wiring, unplug the fuel sender. The gauge should go to empty. Then short together the terminals for the sender. The gauge should go to full. If this happens, the problem is almost certainly with the sender.
