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Discussion Starter · #1 ·
My engine is always knocking and it seems like it should have more power, what should I do to try and kick more engine out of my 2.4. I just bought it from someone who had put flow masters and cold air intake but I am looking for some quick and easy ways to get started on the upgrading my jeep. Also the knocking doesn't seem to be caused by loose belts and when I spray belt lube then it is quiet for a week or two. Any tips would help.
 

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I would 1st start out simple..At your next fill up dump a bottle of fuel injector cleaner in, or maybe in fuel system clearner. See if that helps. Next what octane (spelling?) rating are you running? Sometimes moving to a higher rating will help. From there I would look at a simple tune up. Plugs, wires, fuel filter, o2 sensors etc. is the engine showing any codes.. take it to just about any auto parts store., auto zone, etc..and they can run them for you. Good luck.
 

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Discussion Starter · #3 ·
Where would it display any engine codes. Would I have to take it in to have them check for codes.
 

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On the TJ's is a readout on the dash, not sure if the YJ's do the same thing with perhaps a flashing light. Just call autozone or a auto parts type store in your area and see if they read your codes. Most do it for free.
 

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Try this. I think this is what you are wanting.

Put the key in the ignition and turn the key to run (not start), then off, then run, then off, then run (that's 3 runs and 2 offs). Leave the key in the run position. The check engine light will turn on for a few seconds, then turn off, then (sometimes after 20-30 seconds) start flashing. The flashes are counting out 2-digit trouble codes. Fast flashes count up each digit, with a longer pause between digits. 55 indicates the end of all codes.


Code Description
11* No crank reference signal detected during engine cranking.
12* Direct battery input to PCM was disconnected within the last 50 key-on cycles.
13** No difference recognized between the engine MAP reading and the barometric (atmosphereic) pressure reading at start-up
14** MAP sensor input below minimum acceptable voltage.
or
MAP sensor input above maximum acceptable voltage.
15** No vehicle distance (speed) sensor signal detected during road load conditions.
17* Engine coolant temperature remains below normal operating temperatures during vehicle travel (thermostat).
21** Neither rich nor lean condition detected from the oxygen sensor input.
or
Oxygen sensor input voltage maintained above the normal operating range.
22** Engine coolant temperature sensor input above maximum acceptable voltage.
or
Engine coolant temperature sensor input below minimum acceptable voltage.
23** Intake manifold air temperature sensor input above maximum acceptable voltage.
or
Intake manifold air temperature sensor input below minimum acceptable voltage.
24** Throttle position sensor input above maximum acceptable voltage.
or
Throttle position sensor input below minimum acceptable voltage.
25** A shorted condition detected in one or more of the idle air control motor circuits.
27* Injector #1 output driver does not respond properly to the control signal.
or
Injector #2 output driver does not respond properly to the control signal.
or
Injector #3 output driver does not respond properly to the control signal.
or
Injector #4 output driver does not respond properly to the control signal.
or
Injector #5 output driver does not respond properly to the control signal.
or
Injector #6 output driver does not respond properly to the control signal.
33* An open or shorted condition detected in the A/C clutch relay circuit.
34* An open or shorted condition detected in the speed control vacuum or vent solenoid circuits.
or
Speed control switch input below the minimum acceptable voltage.
or
Speed control switch input above the maximum acceptable voltage.

35* An open or shorted condition detected in the radiator fan relay circuit.
41* An open or shorted condition detected in the generator field control circuit.
42* An open or shorted condition detected in the auto shutdown relay circuit.
44* An open or shorted condition exists in the engine coolant temperature sensor circuit or a problem exists in the PCM's battery temperature voltage circuit.
46** Battery voltage sense input above target charging voltage during engine operation.
47** Battery voltage sense input below target charging voltage during engine operation. Also, no significant change detected in battery voltage during active test of generator output.
51** Oxygen sensor signal input indicates lean air/fuel ratio condition during engine operation.
52** Oxygen sensor signal input indicates rich air/fuel ratio condition during engine operation.
53* PCM internal fault condition detected.
54* No fuel sync (camshaft signal) detected during engine cranking.
55* Completion of diagnostic trouble code display on the malfunction indicator lamp (check engine lamp).
62* Unsuccessful attempt to update SRI (service reminder indicator) miles in the PCM EEPROM.
63* Unsuccessful attempt to write to an EEPROM location by the PCM.

* - Check engine lamp will not illuminate at all times if this code was recorded. Cycle ignition key as described and observe code flashed by check engine lamp.

** - Check engine lamp will illuminate during engine operation if this code was recorded.
 

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I get this code on my 02 Wrangler X:

P0142 - O2 Sensor Circuit Malfunction

What should I do to fix this? Do I just need to change out an O2 sensor or is something else wrong?

Any input would be greatly appreciated. I am trying not to take it in and fix it myself!! Thanks!
 

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Let's see... I hardly give out tech advice. I prefer for people to think I am clueless. ;) I know you have been fighting this one, so I'll give it a shot.

I believe there is an upstream and downsteam 02 sensor. Upstream being before the cat and downstream being behind the cat. The code should indicate which one if faulted. They are not expensive though, and easy to replace. A 7/8 wrench will loosen it up for removal, then you clip the wires. Connect the wires for the new one, and tighten it back in.

Also, I am fairly certain that there is a fuse on the fuse block under the hood that is used for the 02 sensor circuit. Check it out, too.

Let me know if this helps you any.
 

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You know, you also have to consider that your cat may be going bad. Most likely a sensor though.

Nice job on searching the forum, by the way. I don't even remember this thread. You went back in time a bit. The guy we were trying to help in this thread never came back and saw the conclusion. His loss!
 

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>What should I do to fix this? Do I just need to change out an O2 sensor or is something else wrong?

Just change the sensor.

> what should I do to try and kick more engine out of my 2.4

Take that cancer out and get an AMC longitudinal engine put in.
 
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