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Thread: Two Piston Smart

  1. #211
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    I'd suspect boost - or lack of, and hook up something to measure it. Exhaust internals may have collapsed - long shot, but would impact on boost also. 23mpg is way off course. Something's up (or down).

  2. #212
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    Quote Originally Posted by pinger View Post
    I'd suspect boost - or lack of, and hook up something to measure it.
    Any suggestions for a cheapskate like me?
    Paul
    Pure 2000 W, LHD 599cc - Engine Rebuilt Feb 08 - sold
    Passion 2000 W, LHD 599cc - Engine Rebuilt Mar 09 - sold
    Passion 1998 T, LHD 599cc - Engine Rebuilt Apr 10 - sold
    Cabrio 2001 Y, LHD 599cc - Engine Rebuilt Jul 10 Replaced Oct 16

  3. #213
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    Quote Originally Posted by UKKid35 View Post
    Any suggestions for a cheapskate like me?
    Have a look for my 'pressure/vacuum gauge' thread for a link (from RIS) to a place selling cheap gauges. If you can plumb one in temporarily...
    Alternatively, try slackening the clamps on the pipes on the boost side. Start nearest the engine and if the pipe gets blown off, assume there's boost. If not, try another (working towards the turbo compressor. When one blows (when downstream ones don't) upstream there's a blockage. Something choking the intercooler (especially after recent travails) is a possibility. They are quite tolerant of being choked on the inlet side (pre turbo) though, but a rummage in the filter box wouldn't go amiss.

    These engines are gutless and horrible without boost.

  4. #214
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    Quote Originally Posted by pinger View Post
    I'd suspect boost - or lack of, and hook up something to measure it. Exhaust internals may have collapsed - long shot, but would impact on boost also. 23mpg is way off course. Something's up (or down).
    So I reckon you are right

    But it was only while watching Car SOS a couple of nights ago that the fragility of the turbo was drummed in to my head

    They were saying that just using a poor quality air filter would be enough to significantly dent the Scooby turbo's performance

    Since mine has had several grams of aluminium go through it, twice, perhaps it's worth swapping out the cartridge

    Fortunately I have a spare cartridge, attached to a cracked manifold that I removed form an earlier car several years ago

    The turbo spins, but not perfectly freely, perhaps once it is back in use it will free up completely, or perhaps I'm simply deluded

    Either way, it won't cost me anything other than time to swap them over, so assuming it passes it's MOT tomorrow I will give that a go

    It would be good to have some performance back - here's hoping!
    Paul
    Pure 2000 W, LHD 599cc - Engine Rebuilt Feb 08 - sold
    Passion 2000 W, LHD 599cc - Engine Rebuilt Mar 09 - sold
    Passion 1998 T, LHD 599cc - Engine Rebuilt Apr 10 - sold
    Cabrio 2001 Y, LHD 599cc - Engine Rebuilt Jul 10 Replaced Oct 16

  5. #215
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    The problem became immediately obvious when I split the turbo from the manifold

    Here's the old one



    And the spare that I've just fitted



    It seems that although I cleaned up the compressor after the engine failure, I forgot to check the turbine

    Yesterday's test drive was cut short when the engine overheated because I'd introduced an airlock in the cooling system

    I pulled the coolant temp sensor to bleed the system, and then spent forever and several pairs of nitrile gloves trying to refit the U clip

    I'd done this several times before on a cold engine with no problems at all, but fitting this one clip seemed more difficult than swapping the turbo cartridge

    Eventually it became clear that the rubber O ring had swelled (perhaps because of the heat) and wasn't fitting back in the recess in the housing

    Once that was sorted the sensor seated properly and the clip went back on

    A short drive to the shops this morning, which was just enough to bring the engine to operating temp gave me a couple of chances to red line the engine

    It certainly feels much more eager than before, but I'm not sure yet whether it's back to the level of performance of the previous engine

    It will be interesting to see if the fuel efficiency improves

    This was a zero cost fix so I'm pretty happy
    Paul
    Pure 2000 W, LHD 599cc - Engine Rebuilt Feb 08 - sold
    Passion 2000 W, LHD 599cc - Engine Rebuilt Mar 09 - sold
    Passion 1998 T, LHD 599cc - Engine Rebuilt Apr 10 - sold
    Cabrio 2001 Y, LHD 599cc - Engine Rebuilt Jul 10 Replaced Oct 16

  6. #216
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    WOW! That's pretty worn. I doubt that this is your fuel efficiency problem. The engine will only squirt in enough fuel so as to keep the air/fuel ratio correct. Therefore with less airflow (boost) it should of used less fuel, but it sure as hell must of hit the performance.

  7. #217
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    Just a thought, is the engine running rich? This would cause the heavy use of fuel & maybe the lack of performance.
    If I understand the system correctly, the air/fuel ratio is measured by the Lambda sensor & MAF sensor. If either of these are giving a false reading could that be a problem?

  8. #218
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    Quote Originally Posted by Mr T View Post
    Just a thought, is the engine running rich? This would cause the heavy use of fuel & maybe the lack of performance.
    If I understand the system correctly, the air/fuel ratio is measured by the Lambda sensor & MAF sensor. If either of these are giving a false reading could that be a problem?
    Passed the MOT yesterday so I'm assuming it's running OK

    Never get any check engine warnings either (except for the faulty fuel gauge)
    Paul
    Pure 2000 W, LHD 599cc - Engine Rebuilt Feb 08 - sold
    Passion 2000 W, LHD 599cc - Engine Rebuilt Mar 09 - sold
    Passion 1998 T, LHD 599cc - Engine Rebuilt Apr 10 - sold
    Cabrio 2001 Y, LHD 599cc - Engine Rebuilt Jul 10 Replaced Oct 16

  9. #219
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    Quote Originally Posted by Mr T View Post

    If I understand the system correctly, the air/fuel ratio is measured by the Lambda sensor & MAF sensor. If either of these are giving a false reading could that be a problem?
    No MAF on Suprex. Mapped reading manifold pressure, air temp, etc, with Lambda (final) control and then, above a threshold rpm, from the ECU map - I think.

  10. #220
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    Quote Originally Posted by pinger View Post
    No MAF on Suprex. Mapped reading manifold pressure, air temp, etc, with Lambda (final) control and then, above a threshold rpm, from the ECU map - I think.
    Lambda sensors age, and as a result get sluggish and will start to affect MPG ... potentially from 50kmiles onwards

    Emissions will be similarly affected too.
    You're so money supermarket and you don't even know it!

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