Slimy38
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| posted on 19/6/16 at 10:19 AM |
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Testing a coilpack and/or spark plug leads
My 2.0 Duratec has a fairly regular misfire, which I've been informed is potentially a dodgy coil pack and/or plug leads. But I've swapped
them for what I would consider 'decent' replacements, and it hasn't helped.
Having said that, a lot of forum advice suggests that even new parts can struggle on the Duratec, so I was wondering whether there was anything I
could do to test the coilpack or leads, say with a multimeter? My bike coilpacks had a specific resistance range that could be tested, is there
similar for others?
I don't want to buy a third set of ignition parts if the problem is actually somewhere else.
It does have an engine light on, which is the EGR valve malfunctioning. I've cleaned it several times, but I think the EGR valve is a symptom of
the misfire rather than the cause.
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ian locostzx9rc2
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| posted on 19/6/16 at 11:54 AM |
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If you have got an egr fault it can give you misfires and lack of power issues !
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britishtrident
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| posted on 19/6/16 at 12:13 PM |
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Ford specified an excessively large spark gap that creates a very high ignition secondary that puts enormous stress on the insultation of the coil
and plug leads. Ford subsequently reduced the specified gap but it still on the wide side.
Personally I always avoid Intermotor brand leads as the ones they supply for Rover K engines are too long for the plug wells.
Heres is the official NGK method of checking spark plug leads for continuity
https://www.ngk.de/en/technology-in-detail/ignition-cables/diagnosis/testing-of-ignition-cables/
Checking the leads for shorts is also easy you just need a pices of wire connected to a ground I use a normal 12v test lamp (not LED type) because it
has good insulation and a crocodile clip at the other end. With the engine running give the leads a gentle spray of water and run the pointed end of
the test probe along the plug lead looking for leaking sparks.
You can also stress test the coil and lead using an adjustable spark gap tester
Laser 5655 Adjustable Spark Tester
or
Adjustable Ignition Coil Tester Spark Circuit Tester Securely Avoid Fire Tool
Beyond that you would need an oscilloscope to do more tests.
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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Slimy38
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| posted on 19/6/16 at 01:11 PM |
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Many thanks BT, that's the sort of stuff I was after. I went for the Laser one as it's from a uk seller.
Ian, I've ordered a blanking plate for the EGR. Even if I don't leave it in place at least I can find out whether the EGR is a cause or a
symptom.
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hizzi
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| posted on 19/6/16 at 02:48 PM |
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leads were a very common failure on these engines caused by folk pulling the leads rather than the caps to get them out the hole, problem is if you
had this issue it will take out the plugs as well. removes the plugs and look for arcing lines on the ceramic caused by hot spark, if theres lines it
will be missfiring
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britishtrident
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| posted on 19/6/16 at 03:09 PM |
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Video 4 on this page shows how to check for broken down plug wire insulation.
http://www.wikihow.com/Test-Spark-Plug-Wires
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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redturner
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| posted on 19/6/16 at 08:17 PM |
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quote:
Originally posted by hizzi
leads were a very common failure on these engines caused by folk pulling the leads rather than the caps to get them out the hole, problem is if you
had this issue it will take out the plugs as well. removes the plugs and look for arcing lines on the ceramic caused by hot spark, if theres lines it
will be missfiring
I have a few issues with the plugs in my 2 ltr Black top in that I am actually getting cracks all down the ceramic. I fitted a brand new set before I
went to France a few weeks ago and after the first run I had a misfire. started taking plugs out and found No4 vertually split from top to bottom.
Changed it and it ran great. The engine does not overheat and I reckon that I have changed at least half a dozen from various cylinders.....All NGK
plugs.
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