308 THP 150 (EP6DT engine) erratic idle
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  1. #1
    Tadpole
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    Default 308 THP 150 (EP6DT engine) erratic idle

    hi Fellow Puggers.

    Just seeking some advice on an erratic idle and low revs on my Peugeot 308 THP150 (manual).
    It seems at idle the motor is very rough and 'misfiring' but as soon as the revs rise above 3000rpm all is fine and smooth even under load or uphill, also it seems at standstill it is hard to hold the revs at any point as when you hold the accelerator pedal it skips up and down making it very hard to take off from standstill.

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    things i have done to no effect:
    - Replaced Coil Packs
    - Replaced Fuel Filter
    - Checked Spark Plugs, all are fine and not wet or oily
    - My car has always use Premium 95Ron Caltex

    Recently, car went into limp mode and showed up the following error codes:
    P1385 Variable Cam timing solenoid B Malfunction
    P0172 - Mixture Regulation, Mix too Rich


    once these were cleared car returned to normal but rough idle remained.

    Any help would be greatly appreciated.

    HC

  2. #2
    Fellow Frogger!
    Join Date
    Jul 2012
    Location
    Sydney
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    Default

    Hi there,

    What mileage is your car at?

    Three areas to look out for with THP engines.

    1) high pressure fuel pump develops hairline cracks - causes idle issues as described, but more so when cold. As it heats, metal expands on the pump sometimes sealing the crack. Google mini r56 high pressure pump problem to get an idea. If you need a new pump, buy them off ebay for around $300 from the US. Search for a Mini cooper s high pressure fuel pump up to about 2012 year. Not hard to replace yourself. See the following:

    http://www.northamericanmotoring.com...r-r56-jcw.html


    2) Other problem might be timing chain stretched and out of timing. Is the engine quiet or are there undue rattles? Particularly cold start up?

    3) Carbon build up on inlet valves. Try doing this as it may help. Buy a can of nulon foaming intake cleaner or throttle body cleaner and spray it into the PCV hose on the right of the engine coming out of the rocker cover, basically the same hose as seen in the following video. With somebody holding the revs, spray the contents of the can in to the PCV hose (don't use the straw that comes with the can, just straight from the can nozzle into the PCV hose). Switch off for about 15min then restart. Should create a whole heap of white smoke as seen in the video.


    Seafoam treatment on Peugeot 207 GTi - YouTube
    Feb 25, 2012 - Uploaded by Gabriel Yap
    Did a short video of how we can clean the intake valves using seafoam.


    I would however suspect the fuel pump given experiences of Mini R56 Cooper S owners out there. Give the intake clean a try by all means as that shouldn't be too hard or expensive to try. If it's a timing chain, it will be much more complicated, but Collier's automotive in Granville should be able to help (they have done a few now).

    Kaza1





    Quote Originally Posted by puggie308 View Post
    hi Fellow Puggers.

    Just seeking some advice on an erratic idle and low revs on my Peugeot 308 THP150 (manual).
    It seems at idle the motor is very rough and 'misfiring' but as soon as the revs rise above 3000rpm all is fine and smooth even under load or uphill, also it seems at standstill it is hard to hold the revs at any point as when you hold the accelerator pedal it skips up and down making it very hard to take off from standstill.

    things i have done to no effect:
    - Replaced Coil Packs
    - Replaced Fuel Filter
    - Checked Spark Plugs, all are fine and not wet or oily
    - My car has always use Premium 95Ron Caltex

    Recently, car went into limp mode and showed up the following error codes:
    P1385 Variable Cam timing solenoid B Malfunction
    P0172 - Mixture Regulation, Mix too Rich


    once these were cleared car returned to normal but rough idle remained.

    Any help would be greatly appreciated.

    HC
    Last edited by Kaza1; 8th September 2014 at 10:11 PM.

  3. #3
    1000+ Posts TroyO's Avatar
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    Perth, Western Australia
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    Default

    I had a similar problem with my 208 (THP156), erratic idle, misfiring, sometimes going into limp home mode. On warmer mornings it would sometimes be rattly on cold start. But once you got the revs about 2000-3000 rpm the engine pulled strongly. The problem would tend to go away once the engine was fully warmed up.

    It turned out the problem was a faulty high pressure fuel pump, it wasn't providing the required fuel pressure at idle. Replacing that fixed the erratic idle/misfire issues/limp home mode issues at least. Didn't fix the rattly sounding cold start though.
    Last edited by TroyO; 9th September 2014 at 01:36 PM.

  4. #4
    Tadpole
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    Sydney/Australia
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    Default

    Thanks for the info Kaza1.

    Car has covered 125k, it did however have a HPFP changed at about 80k from memory, so this maybe on its way out again.

    Funny thing is there are lights on, on the dash advising of issues. I remember when the Pump failed last time the 'Depollution fault and engine light' came on?

    As for the chain, it does make some rattles in a cold start so this could be pointing to the timing chain too... Urrrgghhh

    i think i will have to give Colliers a buzz and see what they can do.

  5. #5
    sans witticism SLC206's Avatar
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    North Parramatta
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    Default

    Sadly, I suspect you may have a timing issue.

    It could be something like the camshaft dephaser has failed (which could explain why it's unhappy when at idle), although more likely to be a timing chain stretch-related thing.

    When you say you've checked the plugs - did you check the gaps on the plugs?

    How old is the car - is the battery ok?
    Regards,

    Simon

    2018 308 GTi 2011 DS3 DSport
    ----
    2014 208 GTi 2007 207 GTi 2004 206 GTi180 2000 206 GTi 1995 306 XT

    www.peugeotclub.asn.au

  6. #6
    Tadpole
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    Default *update*

    Thank you everyone for your responses... :0)

    Just a little update for everyone, so i did a full service on the car an discovered that the 1 of the turbo air pipes was cracked, so i quickly replaced that and it has made it a little better.

    But to fully diagnose the issue have booked it into Collier's as per advise from Kaza1 (thanks Mate). I think the timing chain has done the infamous 'stretching', ohh well will def find out on Monday!

    For everyone facing the same issue, i did find out that Peugeot will still replace under warranty even past expiry up to 5 years i believe, so long as the normal service schedule has been done etc. there is however the normal dealer submission fees etc (abt $400 is what was quoted)

    Hope that helps anyone facing the same issues as me.

  7. #7
    Tadpole
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    Quote Originally Posted by TroyO View Post
    I had a similar problem with my 208 (THP156), erratic idle, misfiring, sometimes going into limp home mode. On warmer mornings it would sometimes be rattly on cold start. But once you got the revs about 2000-3000 rpm the engine pulled strongly. The problem would tend to go away once the engine was fully warmed up.

    It turned out the problem was a faulty high pressure fuel pump, it wasn't providing the required fuel pressure at idle. Replacing that fixed the erratic idle/misfire issues/limp home mode issues at least. Didn't fix the rattly sounding cold start though.

    If ur still getting a rattle during cold starts, i would not hesitate in getting it checked to see if the timing chain has stretched. chances are you will get it under warranty. (provided your in the timeframes etc)

    cheers

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