Ford Focus (1998 - 2004) - 2000 (x reg) 1.6 zetec missfire

Honest John Back Room » Technical matters
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Thu 21 Feb 2008 14:29
2000 (x reg) 1.6 zetec missfire - tip tip
I have engine management light on took it to 1 garage and they detected 4th cylinder missfire. so changed coil pack, leads and plugs. still no joy missfire still there so taken it to another garage and they've detected 1st and 4 th missfire. they have done compression test passed and all plugs are sparking. i have no idea of the codes detected at the minute but second garage are thinking it could be the ecu. any ideas would be greatly appreciated many thanks

Edited by Dynamic Dave on 21/02/2008 at 19:02

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Thu 21 Feb 2008 15:20
x 00 focus 1.6 zetec missfire - Screwloose

Their next test is to scope the two trigger wires [for cyls 1+4 and 2+3] to the coilpack and compare the signals. It's very easy to see the difference if one is missing.

Failed coilpacks can often damage the switching transistors in the ECU - easily repairable by the ECU companies.
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Thu 21 Feb 2008 15:53
x 00 focus 1.6 zetec missfire - tip tip
thanks screwloose just spoke to the garage and the signals was perfect so could this point to the switching transistors in the ecu?
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Thu 21 Feb 2008 16:06
x 00 focus 1.6 zetec missfire - Screwloose
If they really have scoped the signals and they are identical, then they need to do the same with a running and a non-running injector to check the signal.

[Cyls 1 + 4 failure is nearly always ignition; tell them to make-up 3 links and swap over primaries and secondaries to see if it moves to 2 + 3.]

Also check that it's got the required calcium battery on it.

Edited by Screwloose on 21/02/2008 at 16:09

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Sun 24 Feb 2008 13:24
x 00 focus 1.6 zetec missfire - tip tip
thanks screwloose in the finish it was the ecu so just sent off yesterday to be repaired.thanks for all your help
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Tue 25 Mar 2008 14:55
x 00 focus 1.6 zetec missfire - tip tip
right so a month on ecu came back with no faults. and the misfire is still there wiring has all been checked does anybody have any other ideas what it could be. or could it just be a job for fords?
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Tue 25 Mar 2008 15:06
x 00 focus 1.6 zetec missfire - Screwloose

When you said it was the ECU in your previous post; was that because of an ignition fault - or was there an injector issue? Your garage sound a little too quick to jump to conclusions - they say everything is perfect, when it clearly isn't.

Is it still only running on 2 + 3? Did swapping the coils side-to-side move the miss?

Where did you get the ECU tested and did you check that is the correct calcium battery - sounds impossible, but it does matter.
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