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W245 B1700 petrol 2005/6 cylinder misfire

2930 Views 22 Replies 4 Participants Last post by  Bnut
Hello folks,

This is w245 B1700 petrol 2005/6 with no history, basic runaround.

Cylinder four has a miss determined by pulling HT, removed plug - gap looks huge at 1.1mm although OEM plugs are set to 0,9m which I assume is just under 1mm, not 100% sure as separated by a comma, perhaps denoting something different?

If someone could confirm correct electrode gap that would be great, ordered a set of Bosch which should be here tomorrow.

The coil packs which feed 3/4 has two coils, are these independent of each other, i.e could one coil fail (out of the two) leaving the other working fine?

Complete newbie on this stuff as owned a S124 dinosaur for an age

Thanks for any pointers.
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Changed thread title to more accurately reflect content.

Bit of an iupdate

On the ignition side I had already swapped over both coils leaving HT leads in-situ, this was done a while back along with new plugs trying easy things first. Also pulled plug 4 lead and tested with spark plug (engine running), plenty of spark, in fact almost continuous which I put down to high efficiency engine.

That in my mind ruled out lack of spark but decided (run out of things to change/buy :ROFLMAO:) to swap out HT lead 4 for 3 and clear codes. Total surprise on my part to see code had moved to 3, tried again with 1, same thing which suggests faulty or incorrect lead (even though it knocks out a fair spark having had a few jolts myself while fault finding).

It's also possible the leads maybe incorrect for the car providing too much resistance (or too little), gone are the days when you just bought four foot of HT cable and cut it to length :ROFLMAO: :ROFLMAO::ROFLMAO:

Anyhow, old leads didn't have any OEM numbers so ordered a generic set - can always change later if poor quality.

Hopefully next post will be a thumbs up!
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Wishing you the very best of luck with it.
Thanks, fitted leads and....

...........runs like a top (y)

Thankfully I didn't buy new injectors so parts bill still well under $100 including tester.

Intermotor is a new brand for me but leads look very good quality (not sure if available US).

Cheers for the replies.

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