Focus 1.6 Petrol sooted plugs and funny noise

Gareth Magennis · 2017-10-11T18:08:23+00:00

Hi, my Focus started misfiring yesterday and the idling was going up and down randomly. Took it to my friendly mechanic today who changed the plugs as he said they were sooted. He changed them not so long ago when I bought the car, along with the timing belt. (85k miles) Now, he pointed out a noise on starting I have been hearing for ages. It sounds like a valve fluttering - that's what I thought it was, and was normal. He tells me, I think, that this is the ECU adjusting the cam timing (?) He is Lithuanian, and I don't always get exactly what he is trying to tell me. Anyway, from what I can translate, he thinks there is a problem that he is unable to diagnose right now. The ECU thinks something is wrong somewhere and is doing this fluttering/whirling type noise on startup, and is now trying to compensate for something by changing the mixture and sooting the plugs. His idea is to wait until the problem gets to the point where it can be reliably diagnosed. There was a fault code, but only in the lambda sensor after the cat, which he is dismissing as not much to worry about right now and nothing to do with the current problem. I'd like to know that this whirling, fluttering noise actually is, and how it might relate to the other symptoms. It is literally... Crank, start, whirrrrrrrrrrrrrrr for 1 second or so, normal. Cheers, Gareth.

Oct 11, 2017 21 Replies

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Gareth Magennis 8 years ago

Disconnect them and see if the noise stops.

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Yes I will do that tomorrow. I guess the ECU won't complain unless I try and boot it and get it into VVT world.

Cheers,

Gareth.

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Gareth Magennis 8 years ago

Disconnect them and see if the noise stops.

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Yes I will do that tomorrow. I guess the ECU won't complain unless I try and boot it and get it into VVT world.

Cheers,

Gareth.

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Disconnected both connectors this morning and drove to work. (I'm trying to establish whether the wild idling swings are to do with the VVT or not, but it's a very random occurrence)

Engine management light came on when I started up for the return journey.

After stopping briefly the whirring happened on startup, so this is NOT due to the solenoids operating erroneously. (doesn't whirr every time).

Gareth.

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