2003 Kia Spectra Troubled Misfire

DVALENCIA44

MEMBER
2003 KIA SPECTRA
4 CYL
2WD
AUTOMATIC
60,000 MILES

2003 Kia Spectra-
Randomly misfire on cylinder #1 verified by pulling p0301 as well as p0300 p0302. Spark plug #1 is wet, and is firing. Swapped coil packs to verify. Problem remains in #1. Swapped injector 1 and 3 problem remained in cylinder #1. Compression test verified all cylinders have 150 psi. Cylinder leak down no obvious indications of a problem. When I start it for the first time or after it sits for 5 ten minutes it will run just fine it’s when I put a load on the car is when it starts to misfire and doesn’t recover until it sits for a while. Lost on what to do next.

3 Replies

JACOBANDNICKOLAS

MECHANIC
109,724 POSTS

Have you checked to make sure the injector is getting continuous power?

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Wednesday, October 20th, 2010 AT 8:09 AM

DVALENCIA44

MEMBER
2 POSTS

Yes as it is misfiring the injector is still operating electrically and mechanically. I put injection cleaner in the cylinder let it sit for a while and tried to clean up some of the carbon, because when the car starts to misfire (under load) it pings pretty loud so I naturally suspected detonation/pre-ignition. Yet this problem still persist to be annoying

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Wednesday, October 20th, 2010 AT 4:26 PM

JACOBANDNICKOLAS

MECHANIC
109,724 POSTS

Have you checked the knock sensor? Here is the test procedure. I was able to dig it up for you.

Disconnect the sensor electrical connector.
Remove the sensor from the engine.
Mount the sensor in the jaws of a bench vise.
Connect a voltmeter between terminal 1 and 2.
Wrap the bench vise sharply with a hammer and note the voltmeter reading.
Verify that the voltage spike is less than 1 volt.
If no voltage spike is observed, replace the sensor.

NOTE: You need to remove the intake support bracket to access it.

Let me know. It plays with the timing and can cause the noise under a load, so it's worth checking.

Joe

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Wednesday, October 20th, 2010 AT 10:56 PM