Zetec misfire/loss of power
Discussion
I'm after some ideas of what could be causing a problem I have with my Zetec/Jenveys/MBE ECU powered Westie.
Randomly, when the engine is running, whether it is idling or being revved, it keeps on cutting out for a split second, literally about 1/2 second, and then carries on as normal. During the split second it cuts out, the rev counter drops and when the power comes back, you get a little pop from the exhaust, which is making me think it's ignition/electrical rather than a fuel problem. Once it has done it and cut out for about 5 seconds, in which time the rev counter dropped to zero, but again, when I got power again it was fine.
This started in September, and is totally random, sometimes it will do it 5-6 times in a journey, the next drive it won't do it at all. I have had it looked at by my garage, who thought it was the coil pack, so replaced it plus the HT leads, and it had been fine for a couple hundred miles, but I've just been out for a short drive tonight and it's doing it again
I'm going to take it back so they can have another look, but was wondering if anyone has had this problem themselves or had any ideas? I'm just hoping that it's not something really expensive like the ecu packing up!!
Randomly, when the engine is running, whether it is idling or being revved, it keeps on cutting out for a split second, literally about 1/2 second, and then carries on as normal. During the split second it cuts out, the rev counter drops and when the power comes back, you get a little pop from the exhaust, which is making me think it's ignition/electrical rather than a fuel problem. Once it has done it and cut out for about 5 seconds, in which time the rev counter dropped to zero, but again, when I got power again it was fine.
This started in September, and is totally random, sometimes it will do it 5-6 times in a journey, the next drive it won't do it at all. I have had it looked at by my garage, who thought it was the coil pack, so replaced it plus the HT leads, and it had been fine for a couple hundred miles, but I've just been out for a short drive tonight and it's doing it again
I'm going to take it back so they can have another look, but was wondering if anyone has had this problem themselves or had any ideas? I'm just hoping that it's not something really expensive like the ecu packing up!!
Definitely sounds like ignition side rather than fuel. If it was me I would check all of the wiring that feeds the coils as it may be that breaking down.
Had a similar problem on an old Range Rover years ago turned out it was a wire shorting to earth in the dizzy but only at certain amounts of vacuum advance. You can imagine how difficult that was to find.
Ended up wiring half a dozen lamps into various points in the LT wiring to find it.
Had a similar problem on an old Range Rover years ago turned out it was a wire shorting to earth in the dizzy but only at certain amounts of vacuum advance. You can imagine how difficult that was to find.
Ended up wiring half a dozen lamps into various points in the LT wiring to find it.
alexcollins said:
I have exactly the same issue - totally random and exactly as you state.
Mine's 2.0 zetec on weber alpha throttle bodies & weber ecu.
If we both have same issue with different setups then I'm inclined to think its the coil thats at fault....
I'm assuming it's not the coil pack itself, as mine is brand new, unless I've got a duff one!Mine's 2.0 zetec on weber alpha throttle bodies & weber ecu.
If we both have same issue with different setups then I'm inclined to think its the coil thats at fault....
Don't know if this could cause the sort of issues you're both having....I've a zetec on jenveys with DTA. I'd noticed that occasionally it ran a little rough/lumpy, just a blip really - like a rough idle, you could hear the engine note change at idle. Wasn't anything to cause concern and i put up with it and in the end didn't really notice it that much. When i took it to a r/road for a bit of tweaking they found a problem with the wiring. I'm assuming that the 2 things were related as it hasnt done it since..
the muppet that did the loom for the ecu hacked into another part of the loom and consequently the ecu was getting an inconsitent voltage. I cant recall all the details, buut essentially the alternator was throwing out what it should have but there was a variable loss - to the point where the r/road software was showing warnings that the voltage was anything as low as 9.5.
They took a clean feed for power, and redid all the earth points that ran off it. Just a thought.......
the muppet that did the loom for the ecu hacked into another part of the loom and consequently the ecu was getting an inconsitent voltage. I cant recall all the details, buut essentially the alternator was throwing out what it should have but there was a variable loss - to the point where the r/road software was showing warnings that the voltage was anything as low as 9.5.
They took a clean feed for power, and redid all the earth points that ran off it. Just a thought.......
sounds like a feed to the ecu is dropping out, or that one of the coil drivers in the ecu isn't doing it's job right. get a multimeter out and do some buzzing, you want over 13 volts at the ecu power and triggers whilst engine running.
it could be misfiring because the ecu looses a supply and then get's it back very quickly, so it resyncs and then suddenly goes again, see if you can simulate a similar thing but turning the key on/off very quickly.
it could be misfiring because the ecu looses a supply and then get's it back very quickly, so it resyncs and then suddenly goes again, see if you can simulate a similar thing but turning the key on/off very quickly.
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