c5 RFN engine carbon
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  1. #1
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    Default c5 RFN engine carbon

    Hi everybody,

    2nd post in as many years! Looked thru archive and not so sure that I've got a good overview of solutions to my car's problem. Looking for real life experiences to decoke / remove carbon from top end. Water misting thru throttle body sounds plausible ... but le internet is full of "advice" - most of which I'd be somewhat sceptical of! The Anti Pollution warning has been a feature the car - 2001 2.0l petrol 5speed manual C5 with 176K klms. Bought it last year with 162K. But there hasn't been any noticeable difference in performance - revs really and moves well! But of recent there's been a few seconds before it starts (from stonecold) and then is a little hesitant on take-off for the next 5 or so seconds. After that, moves well!

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    Just wondering what fellow froggers have done to overcome this issue - leaving aside full top end disassemble to remove carbon. Went for a 300k spin on Sunday with last 15 minutes in third at 100 kph ... a nice 5,000 rpm. Car started on Monday first time without the dreaded anti-pollution warning and then after 30 or klms of suburban running - warning message came back.

    By the way, have had the coilpak replaced - and one injector replaced - on separate occasions. Went well for a little while after each ... then returned to "normal" - a la anti-pollution warning.

    By the way, I've heard that BP premium 98 is best particularly as it's the only premium fuel that doesn't use ethanol to boost rating. According to some, the ethanol is not good for inlet side

    Appreciate your wisdoms.

    Cheers
    Fred

  2. #2
    Fellow Frogger
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    They are a little susceptible to dodgy lifters and some cars will have had those replaced early on. They can have issues with carbon build up in the inlet tracts and the suggestion was to dismantle enough to get at it and clean,. However, I think I'd try one of those spray cleaners that you spray while trying to keep the engine running. I think Nulon makes a suitable product, but it's the same idea as the expensive factory product that dealers regularly use on the later EP6 THP engines. Also check the breather hose as it likes to crack as it ages. There is also an air pump in the front left corner from memory that can have a role in causing a pollution warning, but it's an expensive item and you'd probably want to avoid that outlay.

  3. #3
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    Default Hmmm carbon tax !!

    Hi Balouk,
    A few comments from my experience. The early models seem to suffer from the excess of pollution faults. However they do not affect the operation. It is my opinion that it is caused by the computer setting being too ideal and not allowing enough leeway for the real world. This assumes, of course that there are no actual problems. There was several quick changes of the computers and systems in the early years.

    I am not sure why you think the carbon build up is the problem ? However if you use that stuff to treat it I suggest you do it away from a built up area. It burns off in the motor and can cause lots of smoke. The cat may also get very hot ! You could look at the output of the two O2 sensors to see if they need replacing.

    I think the starting problem, which came back as the weather cooled, is software related as well. I never got to the bottom of it but just lived with it too.
    Jaahn

  4. #4
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    Many thanks David & Jaahn!

    Wow - 2 replies! I'm chooffed!

    If I can sort of weave through both of your responses at the same time.

    The dogey lifters .... yes, I've been warned about those but then is it caused by carbon or just the nature of the design? Are there any "prayers" I could offer to keep them functioning proper...

    Will check the breather hose and O2 sensor outputs. I take it they are (a) behind cat convertor (b) in exhaust manifold led-off pipe (or whatever it's called) Will need to get a hold of Haynes or similar.

    The air pump - that's an interesting one - and I've now remembered that mechanic said the pump is no longer functioning due to ingress of water given its location. I'm told the pump is supposed to push air into the exhaust - so it's a pollution thing and perhaps even assists the catalytic convertor to burn off - is that right?

    Not so long ago I had the mid section of the exhaust pipe replaced and was told that the oxygen sensor holder at the rear of the cat had to be re-mounted into the new exhaust pipe. It was interesting that for a couple of weeks after that - there was NO anti-pollution warning. So it could be a faulty sensor? Because if the warning relates to air pump not working, then no change should've occurred.

    And yes, you're right Jaahn - there is no perfomrance issue - the car is a zinger - revs freely and is a joy to drive (I'm sitll looking for a "Warning : No-AL4 on board" sticker for the back!)

    The starting "problem" is not really a problem - just feels like the battery's a little weak .... before that the car was brilliant - would almost start before the key have gone all the way home!

    Appreciate any further wisdom...

    Cheers
    Fred

  5. #5
    1000+ Posts robmac's Avatar
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    These links may help.

    Retrieved by searching for "carbon clean" in the search box atop the page.

    THP (1.6L T) Engine Inlet Decoking/Walnut Blasting


    207 Gti carbon removal

  6. #6
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    Hi Fred
    To answer some of your queries,
    "The dogey lifters .... yes, I've been warned about those but then is it caused by carbon or just the nature of the design? Are there any "prayers" I could offer to keep them functioning proper..."
    They are just a poor design I guess. Mine were a bit noisy when I got it and the same probably or a bit noiser when I sold it 6 years later. However I used a good oil Mobile 1, 5w50. The only time I used some other oil the lifter noise increased a lot ! There would be no connection to any carbon IMHO.

    "Will check the breather hose and O2 sensor outputs. I take it they are (a) behind cat convertor (b) in exhaust manifold led-off pipe (or whatever it's called) Will need to get a hold of Haynes or similar."
    The hoses are under the top silver cover. Take that off and look at the hoses there. I had to repair mine a couple of times. There is a plastic one which I think I sleeved with some other hose and some clips. I believe the air pump puts the air into the exhaust manifold without pipes and draws it from the inlet perhaps. Cannot remember exactly ! (Or is that the exhaust gas recirculation ???) It is a pollution reduction item. However it is a simple item and is probably OK.
    The O2 sensors. There are two, one before the cat and one after. The computer looks at both and also sees what the cat does. All new cars have that now. I was going to replace mine, as they do wear out in any car, but never did Aftermarket sensors are available O/S for a reasonable price and you just splice the wires to the original connectors.

    "The starting "problem" is not really a problem - just feels like the battery's a little weak .... before that the car was brilliant - would almost start before the key have gone all the way home!"
    I looked into this as it seemed like a fuel problem. Leaking off when standing or ? However no problem there. After a while I just accepted it started not so instantly when winter was coming. It never was worse, just not so good as summer ???

    I always used 95 non ethanol fuel if possible as crap fuel almost instantly bought up a light I also bought a scanner to put out the light. A cheap one will do that OK if it make you feel better The spark plug change interval is not too long and new plugs help too. I tried platinum plugs but they were no better than the ordinary ones, however they are cheap now so probably the go. The manuals are available O/S too cheaper than here.
    Good luck and just drive it, Jaahn
    Last edited by jaahn; 27th February 2015 at 10:58 AM.

  7. #7
    sans witticism SLC206's Avatar
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    Quote Originally Posted by Balouk View Post
    By the way, I've heard that BP premium 98 is best particularly as it's the only premium fuel that doesn't use ethanol to boost rating.
    I'd love to know the source of the claim that BP 98 is the only premium fuel that doesn't use ethanol to boost rating.

    Seems bogus to me.
    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

  8. #8
    sans witticism SLC206's Avatar
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    Quote Originally Posted by robmac View Post
    These links may help.

    Retrieved by searching for "carbon clean" in the search box atop the page.

    THP (1.6L T) Engine Inlet Decoking/Walnut Blasting


    207 Gti carbon removal
    1.6 petrol direct injection (THP) valve clogging is not something that a 2.0 EW10 petrol engine would suffer from, I would have thought.

    My understanding is that coking of the 2.0 petrol air ports under the exhaust valves are a totally separate thing - and it may not be the ports but the air pump or hoses. Have any fault codes been read?

    Refer to this thread for some possible causes, Balouk
    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

  9. #9
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    Thanks SLC206Appreciate the archive links - I'd discovered them before but had not read the whole lot ... which I now see talks of air/fuel mix / leaning out. Given that mechanic (Citroen) has said air pump not working ... and the slight hesitancy on initial take-off - which is "cleared"with a couple of pumps of the throttle ... I figure this is the issue.

    I originally thought that the air pump worked full time ... but now see it's only when engines' stone cold. And really, it isn't an issue, if you know what I mean. CAR RUNS WELL ... IT'S JUST THAT DAMN WARNING TONE AND MESSAGE ON START-UP.

    I will need to hook up a Lexia to see for myself .. as an adjunct to mechanic. However, he's a good one - I trust him! He was the one that said BP premium not having any ethanol. Yes, I get where SLC206 is coming from --- different tankers filling at the same terminal gate ... can't be that many variants...? I see there's a water, fuel and plastic bottle test one can do to check the existence of ethanol. Will give that a go.Full report will be posted....

    As a side, I've had the C5 for about nine months... It's been a corker. Until I took it in for a service to another Cit mechanic (not the one I'm referring to above). Immediately after that the car didn't fire immediately .... just a coincidence. Anyhow all is still good - she's runs well.

    And thanks Jaahn, I appreciate your helping me out with your experiences. It's really good stuff - this AF. ... I've been a lurker for a long time now ... it's time to get more involved --- with a Lexia, Haynes and AF - couldnt ask for anything better!' It's always good to understand what the car is doing and have potential solutions to turn to.CheersFred

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