C3 1.2 VTi smoking, constant different fault codes

[Bloopeta]

Hi all, hoping someone can help.

The other half recently bought a 2013 C3 1.2 VTi (based on liking the colour and how clean it was )

Its done 98k miles, and when bought it, all seemed fine.
Not too long after, I changed her coolant, and whilst bleeding the system, noticed it would smoke at higher revs. (Fine on idle and normal driving)

One night after driving around 8 miles, the EML came on (drove fine) n when I got home, read the codes, and came up as CMP Actuator/rear/bank 1/exhaust timing over advanced.

So not knowing history of car, I changed the belt and tensioners (belt was wayyyy overdue), filters, oil. Shortly after drove around 8 miles again, and went into limp mode, misfiring like hell. Read codes, missfire cylinder 3. After some diagnosis, it was spark plug. New set of plugs in.

Car was fine couple of weeks (but still smoking, getting progressively worse) and EML came on again for CMP Actuator Exhaust..
Changed actuator, then 2 days later came up as front inlet actuator.

Since then had various codes for misfires, cat, timing over advanced, rich fuel mixture etc.. (see attached images for some examples) until today, limp mode again, misfiring like hell, turned out one of the new plugs had failed replaced that, and so far driving fine, but still VERY smokey. Ive checked the PCV and theres no splits, and its clean. (Could see evidence on plastic it had been opened before)

Noticed today too theres now a rattle when revving engine from the cat

She really loves the car, dispite it being an absolute headache, and would like to repair and keep if possible, so any help/advice greatly appreciated.

[RichardW]

This the 3 cyl puretech? In which case the engine is probably scrap....

[Bloopeta]

This the 3 cyl puretech? In which case the engine is probably scrap....

For what reason?

[RichardW]

This engine is well known for developing running troubles and burning oil - once you get to the oil burning stage there's not much you can do with it really.

[Bloopeta]

This engine is well known for developing running troubles and burning oil - once you get to the oil burning stage there's not much you can do with it really.

I had read the burning oil is due to carbon bulid up on the piston rings? If thats the case n cylinders are ok, its only a set of rings.
Also read these cars use quite a bit of oil even in top running condition compared to other vehicles (use the term 'top' running condition loosely )

Not too sure if the smoking on this one is burning oil atm, as its more of a grey than blue.

Need to take it up garage really when get some spare time to have it compression checked, and smoke tested for any vac leaks etc

[ozvtr]

Valvoline has a new oil it claims can remove carbon from the rings.

It's very new, however I have not seen it advertised outside the U.S.
Watch the whole video, it's quite informative.

The excess oil consumption has probably destroyed the Catalytic converter. Hence the P0420 code. It may have only damaged the downstream O2 sensor but you would have to replace it to find out (I doubt it tho).

Cam dephaser solenoids can fail or get crap in the screens and give you the P1336 and P0014 codes. You can try swapping the solenoids front to back and see if the code moves.

Not sure on the P0172, it's only pending, which means it was transient. I wouldn't worry about it ATM.

[Bloopeta]

Valvoline has a new oil it claims can remove carbon from the rings.

It's very new, however I have not seen it advertised outside the U.S.
Watch the whole video, it's quite informative.

The excess oil consumption has probably destroyed the Catalytic converter. Hence the P0420 code. It may have only damaged the downstream O2 sensor but you would have to replace it to find out (I doubt it tho).

Cam dephaser solenoids can fail or get crap in the screens and give you the P1336 and P0014 codes. You can try swapping the solenoids front to back and see if the code moves.

Not sure on the P0172, it's only pending, which means it was transient. I wouldn't worry about it ATM.

Thanks m8, very informative.

I was actually considering Sea Foam to try and remove any carbon bulid up?

The Cat is definitely toast, as it rattles at certain RPMs if rev engine when stationery.

Whether the missfires have killed the cat, or whether the failed cat is causing the missfires, is yet unknown.

I did initially clean, and swap the solenoids when the 1st code for the exhaust one appeared, and it didnt follow or come back, but did start getting the other codes instead, so thinking it may still be due to solenoid problem, I replaced them both with new, and sometime after that is when I got the one come up for inlet side

Thing I was most curious about, was alot of codes were relating to over advanced timing, running rich... coupled with the cat bein demolished, and 2 plugs on seperate occasions now failed (both different cylinders each time) I was wondering if its possible the timing could be slightly out/over advanced??

When I changed the belt, I used the dedicated cam/crank locking tools for this engine, so I know that was bang on, and obviously turned over by hand and relocked with tools to double check before starting it.
But I have absolutely no clue how VVT and dephasers work?? I have always owned diesels, and havnt had a petrol for a long long time, long before this modern stuff. (My last petrol was a H reg S2 RS Turbo, and prior to that, a H reg Calibra 2.0 Redtop) so my knowledge previously, cam sprockets were fixed, and that was it lol.

Is there anything I should he aware of timing wise, other than locking the cams and crank as I did with the tools?

[ozvtr]

The VVT system uses oil pressure to advance the cam timing. The solenoids "modulate" the oil pressure in the VVT system. There are inductive pickups that sense the positions if the cam shafts.
You can get problems with the solenoids, the pickups or the camshafts.
Unfortunately your symptoms seem to "move round" and become difficult to diagnose.
Generally speaking, if the VVT system isn't working, you just get poor performance. It should still run fine.
If you get misfires and rich mixture codes, I'd start looking at the injectors. Particularly if you are getting fowled plugs. Could also be a coil pack problem. IIRC these engines have separate coil packs?

[Bloopeta]

The VVT system uses oil pressure to advance the cam timing. The solenoids "modulate" the oil pressure in the VVT system. There are inductive pickups that sense the positions if the cam shafts.
You can get problems with the solenoids, the pickups or the camshafts.
Unfortunately your symptoms seem to "move round" and become difficult to diagnose.
Generally speaking, if the VVT system isn't working, you just get poor performance. It should still run fine.
If you get misfires and rich mixture codes, I'd start looking at the injectors. Particularly if you are getting fowled plugs. Could also be a coil pack problem. IIRC these engines have separate coil packs?

Yes there are individual coil packs for each plug/cyinder

[ozvtr]

The engine ECU can usually catch misfires due to the ignition coil. So a misfire "on unspecified cylinders" is usually from an injector.

[Bloopeta]

The engine ECU can usually catch misfires due to the ignition coil. So a misfire "on unspecified cylinders" is usually from an injector.

Thanks m8, ill look into it.
Funnily enough, when I went to remove the inlet when changing the wetbelt the other week, there was an injector bolt that was loose, so think someone has been playing with them previously.
Since I replaced the plug that was down last weekend, its now ran good for 6 days without any fault codes thrown up etc, but still smoking like a b1tch

Ill get a good look at it this coming week, and do a few tests, as unfortunately for the past 2 weeks, I have been having to use it as a daily, as MOT was due on my Megane, n in my infinate wisdom (and tight arsed'ness) I ordered rear disks and pads online from Germany to save a few quid. Ordered 21st July, the 1st lot went missing, so had to send replacements, was 21st August by the time they finally came, and then they were the wrong ones so had to order from elsewhere, which took almost another week, and now yesterday (Thurs) Ive finally fitted them, and cant get in for MOT until Tues

Just out of interest, would something like these eBay specials be ok? Or would you advise sticking with OEM?

https://www.ebay.co.uk/itm/394679647721 ... media=COPY

[ozvtr]

I cant recommend the Chinese injectors (at 28 pound, they can't be OEM ).
HOWEVER, I have replaced 2 sets of faulty OEM injectors in two TU3JP engines with Chinese injectors (8 injectors) and had a failure of 1 Chinese injector. Both engines have run fine for the last 2 years.
By comparison to the cost of OEM injectors, you could afford to get a few sets, incase of failures.
Again I cant recommend them, but they are so cheap, what do you have to loose?
P.S. I think you could get them cheaper from AliExpress.

[Bloopeta]

Had a bit of time to look over things regarding C3 today now Megane is all done and MOT'd

Plugs are fouled black and oily after inspection, oil level is dropping dramatically and needs to be topped up every 7 days and exhaust is emitting quite dense smoke which isnt immediately apparent upon startup when cold, but increases once warmed, worsening further under acceleration which would lead me to believe it is piston rings rather than stem oil seals.

Decided to try a piston soak before anyting to see if carbon build up/stuck rings could be the issue. Goin to soak for probably 72 hours in total, periodically rotating engine by hand every 6 hours or so, checking levels and topping up if required.

[Bloopeta]

Just an update, did the ring soak with a mix of ATF and Acetone over past few days.

Took it out last night for an 'italian tune up' for a good 30 - 40 mins and after the initial bad smoking you would expect burning everything off, the smoking has now stopped. Checked plugs after, and are now how you would expect a healthy engine not burning oil to look.

Too early to tell if oil level will drop at all, as I changed the oil that was already in after performing the soak, and replaced with fresh before starting it, but have changed it again for fresh today, with new filter, so will monitor and report back in 7 days time.