Slight mis at idle

[Belle-ile-blue-ds3]

Hi guys

Ive had a lumpy idle on my 155 sincesi got it a few months back and i just cant solve it so far its had

New spark plugs
Walnut blast (cured hesitation between 2-3k)
Hpfp (seems slightly better, and pressures now holding but no cigar)



Other than this it drives spot on, nice quiet engine, good mpg, pulls well, no excessive oil use etc.

Any ideas?

Kyle

[Chris_Blue]

what fuel? sounds like a fuelling or electrical issue- that's where I would start. Try Shell V-Power
Plugs correct and gapped ok?
leads all good- maybe swap out leads

get a tin of BGK 44 and give the car a good burn up.

[Belle-ile-blue-ds3]

Running half way through my first tank of v power

Spark plugs new, checked gap out the box
Leads? Not sure if im being stupid but do you mean ht leads? Cause this is on pencil coils straight on too the plugs

[Chris_Blue]

Thought about the injectors? yes- I was thinking HT Leads.
Have you checked for fault codes via the OBD- Spect somebodys checked that already?

[Belle-ile-blue-ds3]

Yeah I've thought about them but can't find people having issues with them without it being caused by a failed hpfp, as far as I've aware this hasn't had one completely fail but it's a definitely a possible cause

No codes etc, all seems good on torque app, never had live data taken with a proper diagnostic kit tho

[Chris_Blue]

Yeah I've thought about them but can't find people having issues with them without it being caused by a failed hpfp, as far as I've aware this hasn't had one completely fail but it's a definitely a possible cause

No codes etc, all seems good on torque app, never had live data taken with a proper diagnostic kit tho

No codes- that's strange. is your air filter all clean and new?

[Chris_Blue]

how many miles the engine done

[Belle-ile-blue-ds3]

New mtc induction kit fitted, fault was present before this tho

44k on the clock, seems worse with ac on. Does seem like fuel to me

[Belle-ile-blue-ds3]

P. S cheers for the help by the way

[Chris_Blue]

I had torque pro blutooth, and that missed fault codes. If its misfiring I cant see why there is no fault code. Maybe get hold/ borrow a decent reader
Thought about the fuel filter?

[Belle-ile-blue-ds3]

One of my work friends has got a scan tools ill double check with that when i can, to be fair it's not a bad miss just a lumpy
Think the fuel filter is built in to the pump ?

Took some readings yesterday

Timing is good, jamie at sp said it was spot on when he done the walnut blast a few weeks back.
Unsure of Injectors, or a way of diagnosis without just removing and getting them cleaned and tested.
Ltft1 is - 3.1%
Intake pressure is 5.8 psi, what I don't under stand as it's at about 10hg vacuum on the boost display.
Ignition advance is fluctuating from - 1.5 to 6.5 degrees
O2 1 is fluctuating from 0.1 to 0.8v
02 2 is holding pretty steady at 0.8v
A lot oh these readings don't mean much to be hopefully they do too you?

[Chris_Blue]

One of my work friends has got a scan tools ill double check with that when i can, to be fair it's not a bad miss just a lumpy
Think the fuel filter is built in to the pump ?

Took some readings yesterday

Timing is good, jamie at sp said it was spot on when he done the walnut blast a few weeks back.
Unsure of Injectors, or a way of diagnosis without just removing and getting them cleaned and tested.
Ltft1 is - 3.1%
Intake pressure is 5.8 psi, what I don't under stand as it's at about 10hg vacuum on the boost display.
Ignition advance is fluctuating from - 1.5 to 6.5 degrees
O2 1 is fluctuating from 0.1 to 0.8v
02 2 is holding pretty steady at 0.8v
A lot oh these readings don't mean much to be hopefully they do too you?

No, not to me either. I thought fuel filter was in the fuel tank, but I could be wrong. am on several forums and think abouyt several cars LOL
Lumpy idle, or lumpy under stress (Accelerating)

It sends me staright back to fuel pump, possibly dirty injectors but at 44k miles sounds a bit early

[Belle-ile-blue-ds3]

Yeah that's what I've been told, presumably this is accessed from under the rear seats?

I'm leaning more towards Injectors but it makes no sense, if i hold the revs up slightly it is perfect. It's only with no throttle input it is lumpy. Cars testing me already

[Barola]

Yeah that's what I've been told, presumably this is accessed from under the rear seats?

I'm leaning more towards Injectors but it makes no sense, if i hold the revs up slightly it is perfect. It's only with no throttle input it is lumpy. Cars testing me already

I have the same problem with lumpy idle. Everything else works great. Professional Wynns injector cleaning done, new spark plugs, ignition coils, intake valves cleaned, timing done, hpfp pump changed. I believe it has something to do with valve cover and PCV valve not working as it should. Valve covers are known to be an issue on very low mileage cars. My car has 80k km.

[Chris_Blue]

How about popping into the local Citroen dealer and ask to speak to the lead technician
Ive done this before but seemed to know more about the cars issues than him (So he was suggesting)

That was when they tried to flog me a Brand new DS3 Racing for £26k ! Must have been about 2012