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Thread: Astra Coupe 1.8, misfire and wont rev.

  
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    Astra Coupe 1.8, misfire and wont rev.

    Son's car giving me some grief
    Astra 1.8 (Z18XE 2002), will only rev to around 3500rpm, goes very 'wooly' and misfires, emmision light comes on at this point. Sounds like it's short of fuel or the timing has gone way retarded.
    My fault code reader picks up codes for 'misfire detected' but varies on cylinder numbers. Tech 2 shows up multiple misfires, nothing else.
    Recently serviced so filters, plugs etc. are new but have tried a different set of plugs, a new coil pack (non genuine) a genuine coil pack from a donor (for good measure), fuel pressure checked (ok), inlet pipe checked between MAF and manifold, all to no avail.
    Exhaust dropped from the bottom of the cat (in case of blockage) but no different. Looking up into cat, looks ok but can't be 100%, next step maybe remove O2 sensor from manifold in case cat is blocked but I'm not hopeful. Possibly MAF or ECU??
    Anyone got any ideas for me?

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    Type in 'pedal test' on here. That will give you the exact codes and if you bosh them up here, someone will know the exact sensor you need to replace. Thats what sounds like the problem is being caused by.
    I>< Silver Coupe ><I

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    Quote Originally Posted by IainL View Post
    Type in 'pedal test' on here. That will give you the exact codes and if you bosh them up here, someone will know the exact sensor you need to replace. Thats what sounds like the problem is being caused by.
    Wish it was that simple. Don't need to do the pedal test, used a code reader and vauxhalls tech2.
    No faults showing on any sensors.
    Codes from my code reader are.
    P0301 misfire detected cylinder 1
    P0302 misfire detected cylinder 2
    P0303 .......cyl3
    or P0304 ........ cyl4, these in any combination sometimes just 1 cylinder sometimes all 4 depending how long you keep it running with the misfire going.
    Tech2 shows misfire ... multiple cylinders. NOTHING ELSE !
    So please read and understand before suggesting things like 'pedal test' as it is simply not relevant. I was getting all hopeful when I saw there was a reply

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    have you checked the timing hasnt jumped in anyway?

    what about the injectors? then again not sure how youd go about checking these

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    Z18Xe can suffer from crank sensor and knock sensor problems that cause misfire. could be worth getting the signals from these two sensors scoped if you have access to tech 2 or similar

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    I reckon its the precat,
    expensive i know
    so i wouldn't bet my life on it!

    bri

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    Thanks for the replies guys, it has already been on the Tech2 (saturday morning) at vauxhall dealers and only thing they could pick up was misfire on multiple cylinders. They thought possible blockage in cat (it's the type built into the manifold on the Z18XE) or the ECU, so may be going back in wednesday for further investigation if I can't come up with any answers myself. Going to try taking out the O2 sensor in the manifold (if it's not too tight in there) and run it with this out, if it's ok then the cat is blocked, if not? looks more and more like ECU problems.

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    UPDATE..
    Took the O2 sensor out of the manifold tonight, car revs cleanly. looking in through the sensor hole it is fairly plain that the honeycomb has broken up in there, although it looks fine from other end.
    Now all we need is a new cat, bit pricey but at least it's not the ECU.

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    I'm glad you might have found the answer,
    I once had a friend with an escort, and it wouldn't rev very high with intermittant power and it turned out to be the front cat US,

    Sorry i can't help you with a spare but they do come up on ebay from time to time,
    Or maybe someone on here has one, Beeson1987 is braking his coupe on here (title ; breaking 1.8 coupe)

    Free bump

    Bri

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