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Ford Ka 1.3 2008 - Misfire under load (Waveforms) - Fixed #

Posted by Malcolm Tripp on October 15, 2012, 3:11 pm

Year of Manufacture *: 2008
Engine Size and Code *: 1.3
( Optional ) Scanner Used: PICO

Need some opinions on these captures,
Had a Fiesta in last week with misfire under load did scope it but forgot to save captures, however Ka in today with same engine and no running problems, did same captures which appear to be the same as Fiesta.

Primary/current appears to show a double trigger, is this a new feature to carry out a complete burn ?

Secondary mirrors primary?

Cam/Crank signals don't appear to line up is this correct ?

your thoughts appreciated.

Re: Ford Ka 1.3 2008 - Misfire under load (Waveforms) #

Posted by Chris Angus <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT5111' width='330' height='300' border=0 style='border:none;'> on October 16, 2012, 1:02 pm, in reply to "Ford Ka 1.3 2008 - Misfire under load (Waveforms) #"

Hi Malcolm, these do fire twice, so is normal.
When you say it misfires under load, does it missfire during a snap throttle test?

I see this quite a lot and it's hard to spot on the scope. You'll probably find the spark is tracking down the side of the plug, due to poor insulation. You can sometimes see a tiny tracking line down the plug insulation.
It was many many years ago I first saw this problem and for some reason it's always fords, I probably due to the large plug gaps, and under load it will follow a path to least resistance.

Either replace the leads or make sure they're connected properly or a good quick repair is to apply some silicone grease to the lead end that pushes over the plug, this will insulate and ensure it slips over correctly.

Part number from ford is 1197919, we use it alot, especially when just replacing plugs.

Hope this helps

Chris

Re: Ford Ka 1.3 2008 - Misfire under load (Waveforms) #

Posted by Mark Carter <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1428' width='330' height='300' border=0 style='border:none;'> on October 16, 2012, 4:28 pm, in reply to "Re: Ford Ka 1.3 2008 - Misfire under load (Waveforms) #"
Mark Carter

As Chris has said above with just one thing added.

The double spark is not across the whole rev range, its just at idle and cruise.

Some BMW's can spark up to 7 times per firing sequence.

Mark

Modern cars, Its all wizardry and witchcraft

Re: Ford Ka 1.3 2008 - Misfire under load (Waveforms) #

Posted by Dave Hill <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT2783' width='330' height='300' border=0 style='border:none;'> on October 16, 2012, 4:47 pm, in reply to "Re: Ford Ka 1.3 2008 - Misfire under load (Waveforms) #"

Hi Malcolm

I recall the same questions when I first witnessed this kind of waveform.

It's great how scoping reveals these technologies isn't it!

Link: Multi Stike Ignition Topic

Re: Ford Ka 1.3 2008 - Misfire under load (Waveforms) #

Posted by malcolm tripp <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT5337' width='330' height='300' border=0 style='border:none;'> on October 18, 2012, 8:07 pm, in reply to "Re: Ford Ka 1.3 2008 - Misfire under load (Waveforms) #"
Malcolm Tripp

Well we had the original car back today, the plugs and leads were replaced this time last year to cure a misfire that's why I discounted them from my investigations.

Big mistake ! 3 of the crimped on ferrules that connect to the plugs had become detached, another new set of plugs and leads and all is well.

Still a question mark over cam and crank signal not lining up, could it be the cam peak is so many degrees before the crank signal to the right in the pattern to allow injection before TDC ?

Re: Ford Ka 1.3 2008 - Misfire under load (Waveforms) #

Posted by Mark Carter <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1428' width='330' height='300' border=0 style='border:none;'> on October 18, 2012, 10:09 pm, in reply to "Re: Ford Ka 1.3 2008 - Misfire under load (Waveforms) #"
Mark Carter

The Reference mark on the crankshaft is not normally at TDC, it's normally "X" number of degrees before TDC.

Mark

Modern cars, Its all wizardry and witchcraft

Fixed #

Posted by Malcolm Tripp on January 25, 2013, 4:25 pm, in reply to "Ford Ka 1.3 2008 - Misfire under load (Waveforms) #"
Message modified by board administrator January 25, 2013, 6:23 pm

Once I determined these patterns were normal I had the original Ka back in and replaced the plug leads with genuine Ford and the problem was resolved

Malcolm

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