I haven changed the fuel pump, crank and cam senors, ingnition coils, and the fuel pressure regulator is next. Now I still get the 1123 code and the 1128 as a pending code. The car is also overheating on the highway when I tried to pass someone but the temperature comes back to almost normal when I continue highway speed. After the fuel pressure regulator I have to check the evap system.
Firstly, these codes are set when the fuel 'TRIMS' are out of spec (either tool LEAN - P1123, OR too RICH - P1128).
The air/fuel control system, in addition to a number of sensors, includes the following components and systems:
a.
Intake air system.
b.
Exhaust system.
c.
Evaporative emissions control system (includes purge control solenoid valve).
d.
Fuel injectors.
e.
Fuel pressure regulator.
f.
Fuel pump.
For the air/fuel ratio to be within limits, all of the sensors, components and systems associated with the air/fuel control system must function within normal parameters.
STOP replacing parts/sensors unless you can VERIFY they are defective!
The Powertrain Control Module (PCM) on Hyundai OBD II vehicles (all 1996 and later models) can adjust the engine Air to Fuel (A/F) ratio to compensate for variations in operating conditions. This adjustment only takes place during "Closed Loop" operation.
The PCM uses input from the following components to determine the amount of fuel to deliver:
The ability to adjust the A/F ratio enables the PCM to compensate for engine, fuel and sensor variations as well as temperature, altitude and humidity. This enables the vehicle to maintain a stoichiometric (14.7 to 1) A/F ratio that will ensure optimal engine performance and minimal emissions.
Since the PCM can change the A/F ratio to compensate for a wide range of conditions, an indicator is needed to identify that a compensation has been made. Fuel Trim values shown on the HDS scan tool are the primary indicator that an adjustment in fuel delivery has taken place.
The scan tool displays the PCM's A/F ratio compensation as "Short Term" Fuel Trim (ST TRIM), Long Term Fuel Trim (LT TRIM), and "Oxygen Sensor" Trim (TRIM B1 S1 and B1 S2). The most beneficial diagnostic information comes from "Short Term" Fuel Trim and "Long Term" Fuel Trim.
AFTER ALL THIS, I think it's simply your Coolant Temperature Sensor giving 'FALSE' information to the engine control module/powertrain control module (ECM/PCM).
Blown head gaskets would be the problem
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this is what you must do. make sure that your radiator fun is working you must wait till the car is hot be for it come on for about 5 to 10 min if it doesn't come on your fun or your Coolant Temperature Sensor is bad and you must replace it.and that should take care of your problem. get back to me and let me know if i helped you.
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