Misfire

[Flat6speed]

2000 base stick w 122K mi.  Running like sh*t.

 

 

 

P1117  Code14 Heating power O2S behind cat.c. bank 1.

 

P0300  Code 62 Misfire damaging to cat.

 

P0305 Code 67 Cylinder 5 Misfire damaging to cat converter

 

P030A Code 66 Cylinder 4 misfire damaging to cat converter.

 

 

 

 

I assume (and I know its never good to assume) its time to replace the coils.

 

[JFP in PA]

2000 base stick w 122K mi.  Running like sh*t.

 

 

 

P1117  Code14 Heating power O2S behind cat.c. bank 1.

 

P0300  Code 62 Misfire damaging to cat.

 

P0305 Code 67 Cylinder 5 Misfire damaging to cat converter

 

P030A Code 66 Cylinder 4 misfire damaging to cat converter.

 

 

 

 

I assume (and I know its never good to assume) its time to replace the coils.

 

P1117 indicates a low current condition on on the heated O2 sensor ahead of the cat on bank 1.  This can either be a bad heater or a wiring issue.  Check the sensor resistance using a digital multimeter on pins 1 & 2; you should see 1.8-2.5 ohm, if you don't the sensor heater is gone and you need to replace the sensor.  All of the rest of the codes refer to the misfire on cylinder 5, which could be a loose connector, bad coil, or fouled plug.

[Flat6speed]

Thanks for the reply JFP.  Can you tell me the firing order on my car? And do you think one issue would cause the other?

 

Scott  

[JFP in PA]

Thanks for the reply JFP.  Can you tell me the firing order on my car? And do you think one issue would cause the other?

 

Scott  

 

Firing order is 1-6-2-4-3-5.

 

Possibly, but in any case possibly dead heater in an O2 sensor is going to alter how the car runs.

[Flat6speed]

So I pulled the number 4 bank spark plug.  I was expecting to see a fouled plug.  What I was not expecting to see was a spark plug with 4 missing electrodes.  Is this normal?  Or let me rephrase that.  Is it normal for a spark plug to burn through the electrodes when ran past its life span. 

[JFP in PA]

So I pulled the number 4 bank spark plug.  I was expecting to see a fouled plug.  What I was not expecting to see was a spark plug with 4 missing electrodes.  Is this normal?  Or let me rephrase that.  Is it normal for a spark plug to burn through the electrodes when ran past its life span. 

 

Do the electrodes look burned away (melted) or are they just missing?

[Flat6speed]

Hard to tell. I think they are burned away.

[Hilux2400]

Have you pulled the other plugs? 

[JFP in PA]

Hard to tell. I think they are burned away.

 

That should not happen.  I would suggest two things:  Change your plugs and then have the vehicle scanned (using a Porsche specific scan tool) looking at the fuel trims.  It may also be a good idea to have the cylinders with the missing plug electrodes bore scoped.

[Flat6speed]

I pulled the other plugs and the remaining 5 looked good. Installed new plugs but it still was misfiring. I took it to my Indy.  They replaced the coils and the car runs smooth.  They scoped the cylinders and found no issues. They said the fuel was lean in all cylinders and suggested running an additive to clean up fuel injectors and return in a week.  They said they have never seen a plug like mine.