1.6 THP (155) Misfire and 'Limp Mode' AFTER Dealer Fitted New Timing Chain

[Norbs]

Bought a DS3 (155 THP, 35000miles) in January from an Evans Halshaw (big mistake). Started to have rattling/knocking sounds when revving between 2k and 3k in March. The car went in and after EH messed about they agreed to replace the timing chain and all associated pieces. All is well until I pick the car up and it's still giving Engine Warning light and EH are pulling misfire codes. They fitted a set of new sparks and it ran smoother but fixed as I found out 10 miles towards home.

I took it home, only to have the car to go into to the all too familiar 'Limp Mode'. I had an AA guy out who was great! Spark Plugs and Coil Packs all sparking perfectly. Cylinder compression perfect across all 4.
Running at idle we still pull error codes:
P1336 - Random/Multi cylinder misfire.
P1340 - Ignition failure, C4 misfire.
P1338 - Ignition failure, C2 misfire.

From this, I'm thinking that the problem must be fuel realted. Are the cylinders fed in pairs in the THP engine? I'm not sure?
The only other information I can provide is that today the car went into 'Limp Mode' so I pulled over and while letting the car sit on a VERY rough idle, I pulled the connectors for C2 and C4 and the engine did not change! So the car was literally only firing two cylinders?! Again, sparks, coils and compression should be good?

So I would assume fuel problem HOWEVER reading ignition stats with the AA guy, we found some very odd readings that I shall show in the attachments below. These pictures make me think that this problem is ECU related?

I'm really stuck and I need a reliable pocket rocket back! Also considering a PCV hose delete as it wouldn't hurt.

[Funky]

This sounds like the all too familiar carbon build up in the inlet valves. THP's are very susceptible to this and the best way to sort the issue is to go to Jamie@SPTuning for a walnut blast. Search the forum for "walnut blast" and you will find loads of threads about it.

[BenS]

Or HPFP.

[Jamie@SPTuning]

Or HPFP.

I agree, pump failure.

[Norbs]

Thanks Funky and BenS for your responses. I'm going to try a tin of BG44K next week and see if it makes any difference, otherwise Jamie look out for a pm from me haha. I've just done a 200+ mile trip down to Cornwall for a short break and cruised 80-90 with no problems. Only had one limp mode moment when I wasn't gentle enough on acceleration in 6th gear from 65 upwards. In neutral the engine seems to have a slow, rough rev to 2K, after 2K it revs up as expected. I'll keep this thread updated once I run a tank of fuel + BG44K through.

[Funky]

I forgot about the HPFP. Jamie and Ben are more likely to be correct, so try that first. If that doesn't clear it, go for a walnut blast at Jamies.

[Chris_Blue]

same error codes as when my HPFP went

[BenS]

Yeah the rough idle is one of the main giveaway symptoms when paired with misfires.

[Norbs]

Just read Jamie's thread on replacing the HPFP (http://www.ds3club.co.uk/showthread....PFP-on-the-THP). Looks like I'll be finding a breakers or trying to get hold of an R56 Mini HPFP to fit to my DS3. Oh what a joyful first 4 months it has been with this car!

[Norbs]

UPDATE: Ran a full fuel tank with BG44K through my DS3. Also drained the oil a little as I noticed it was staying a little above max. The car is running much better now. When cold the car runs smoothly but without any increase in boost after 2-2.5k revs. Once warm and an engine restart, the car behaves perfectly again. I think this may be because the engine management light is on and the ECU is putting the car into a protective type mode I'm not sure. Need to get my hand on a computer to reset and pull codes if it throws them after that. I will keep this thread up-to-date as and when I feel like my problems aren't all over.

Sidenote: Had a rear spring go, spent a pretty penny on a new pair (Ł200 springs + Ł70 labour). My mechanic had a time finding new spring as the colour codes have changed since 2012 for anyone interested. Also put 2x Cooper ZEON CS-SPORT on the front and they are sticking really nicely.

[Chris_Blue]

UPDATE: Ran a full fuel tank with BG44K through my DS3. Also drained the oil a little as I noticed it was staying a little above max. The car is running much better now. When cold the car runs smoothly but without any increase in boost after 2-2.5k revs. Once warm and an engine restart, the car behaves perfectly again. I think this may be because the engine management light is on and the ECU is putting the car into a protective type mode I'm not sure. Need to get my hand on a computer to reset and pull codes if it throws them after that. I will keep this thread up-to-date as and when I feel like my problems aren't all over.

Would be surprised if this cures the problem- but hope it does.

[lfcrule1972]

I agree with you Chris, if the intermittent fault is down to HPFP failure then, like Arnie, it will be back

Norbs - is the HPFP not covered under a warranty when you bought the car ?

[Grimsdale]

I have experienced exactly the same as you Norbs, only it is my daughters car now and of course I feel obliged to help her out with it.
Was advised by my garage that it was more than likely now the HPFP, having put on new Coil Packs, Plugs, I did have the timing chain replaced and a defazer unit (whatever that is) and still it is playing up. Spoke to Jamie and he suggested they look at the inlet manifold which I'm told they are going to do now. I am knee deep in cash for this thing, I truly hate the car for the issues it has caused me, and Evans Halshaw btw..........wide berth required.
Did you get it sorted finally Norbs?
I must say thanks to Jamie for the advice , wished I could have got the car there.

[BenS]

Jamie knows a hell of a lot bout the THP engines, unfortunately the early models did have a lot of very expensive potential faults, and it looks like you had the misfortune to meet all of them but the dreaded piston cracking

[Jamie@SPTuning]

Hope you get it sorted soon because when they’re running right they’re actually really good.