Citroen C4 P0303

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Citroen C4 P0303

Postby GRUSS » Sat May 05, 2012 5:21 pm

First time i've had a look at ign.waveforms. Car was a 2005 citreon c4 1.4 16v with P0303 cyl. 3 misfire detected

Removed the coilpack and used the secondary ign probe wires. Hooked the scope up and had a look...
c4 ign no 3.psdata
(675.02 KiB) Downloaded 247 times


I've tried uploading the full file but it wont let me (10Mb) The scales arent probably right but its my first time :?

What is going on with no 3, could someone please explain?

The car didnt have a dead miss and would drive ok once the revs were up so i didnt suspect the coil pack. It was a sparkplug at fault in the end...i swapped plugs aroound and the fault followed.

I have so much to learn about these wavforms. I suppose i should of done a snap throttle test?

c4 no 3 image.gif
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Re: Citroen C4 P0303

Postby GRUSS » Tue May 08, 2012 7:10 pm

I've been thinking today...
On the red trace which is cylinder 3 I remembered hearing a arching noise every now and again coming from the depths of the cylinder head where the spark plug sits. Does the waveform look like it does because the spark is arching from the plugs porsaline to the cylinder head spark plug tube?

I inspected all the plugs but couldn't see any cracks although I imagine the spark finds its way out to ground?

The car runs great now although the em light does come back on after the 4th start...

U1218 CAN bus, multifunction control module no comms

This one in before along with the misfire DTC but I dismissed it thinking it was just a random can bus no comms code. I can't seem to find any info on this. I presuming it's to do with the info display. I could check/scope the can lines into this unit?
I'm waiting on citreon getting back to me tomorrow. Does anybody have any ideas? :)
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Re: Citroen C4 P0303

Postby Robski » Tue May 08, 2012 7:57 pm

What scanner are you using ?

Can you explain how you had all four channels hooked up in the screen shot ? because if they are all on different secondary extension leads (plugs) why do they fall in the same place ??

Were there any tracking signs down the porcelain ?
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Re: Citroen C4 P0303

Postby GRUSS » Tue May 08, 2012 8:02 pm

Robski wrote:What scanner are you using ?

Can you explain how you had all four channels hooked up in the screen shot ? because if they are all on different secondary extension leads (plugs) why do they fall in the same place ??

Were there any tracking signs down the porcelain ?


Hi rob
I'm using some obd2 software with my laptop

To be honest with the actual scope testing I have no idea, I just set one channel up first then opened up the other channels. :? Is it something to do with how I've placed the trigger?

I couldn't see any tracking although there were some dark markings at the base of the porcelain.
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Re: Citroen C4 P0303

Postby Robski » Tue May 08, 2012 8:54 pm

For one i would get a better scanner on it & do a Global scan.

Unless there is something in the scope to allow i can't get my head round all 4 secondary events happening at the same time ??

None of them look like nice secondaries :(
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Re: Citroen C4 P0303

Postby GRUSS » Tue May 08, 2012 9:00 pm

Rob
Do you know if I can somehow compress the original file so I can post it or is there a drop site?

As this is my first look at the secondary's I cant really say. :? This is very new to me.
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Re: Citroen C4 P0303

Postby Robski » Tue May 08, 2012 9:08 pm

Catch me tomorrow & I'll help you out with the file.
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