bloody stuttering!!!!!!!!!!!!!!!!!!

[chunky]

I have replaced my leads,plugs,dizzy,rotor arm,all hoses for silicone,k&n panel filter fitted and still she stutters under heavy acceleration!! any ideas please!! would the coil breaking down cause this?

[t5 stealth]

possible crank sensor ?
possible coil ?
does it throw up any engine light,
maybe check for fault codes if any to see if its logging anything,

[LeeT5]

If it is stuttering under load then its your ignition coil starting to break down. Fact is it will be giving a weak spark all the time, you just won't notice until the engine is made to work hard.

Replace the coil. Never ever known a crank sensor go down on an 850...normally the Camshaft sensor pack up.

[Joolz_850R]

Possible fuel filter. Ive had it where the car will drive quite normal until you need to move quickly. Turned out to be the fuel filter was clogged.

[silverswedemachine]

Plug gap?? Run mine at 0.7mm

[chunky]

i have new filters,plugs etc so i think coil is the only thing left lol will post the results.thanks for the comments

[glock19]

What boost level are you on ? Is your car chipped ?

[Flatout Phil]

If it is stuttering under load then its your ignition coil starting to break down. Fact is it will be giving a weak spark all the time, you just won't notice until the engine is made to work hard.

Replace the coil. Never ever known a crank sensor go down on an 850...normally the Camshaft sensor pack up.

My thoughts entirely.

[chunky]

car is not chipped,running standard boost as far as i know.although she goes much better than my last one which had boost control valve and was running much higher boost!? bit of a strange one as it is black with t5r interior,suspension etc but standard bumpers all of which came from factory!? as i have all receipts from new.

[glock19]

Standard boost means about 0.6-0.8 bars and I assume you don't have a boost meter to confirm. You need to check your hoses going into the wastegate actuator. If there is a leak (usually at the wastegate inlet which is angled), the opening of the wastegate is delayed. You will have a sudden burst of power but because your ECU is not chipped, the MAF will arrest the increased boost pressure and the stuttering comes (boost cut feature).

[JezF]

possible crank sensor ?

I had exactly this on the LPG system, it stuttered horribly at higher rpm. Took a year for them to suss it.

[woz]

did you change all 6 HT leads?
I changed my plug leads and found the fault was the main coil ht lead. Same symptoms. Instant cure though

Thought about getting Sun diagnostic done (or similar) they can usually pinpoint ignition faults?

[Dvfine]

Standard boost means about 0.6-0.8 bars and I assume you don't have a boost meter to confirm. You need to check your hoses going into the wastegate actuator. If there is a leak (usually at the wastegate inlet which is angled), the opening of the wastegate is delayed. You will have a sudden burst of power but because your ECU is not chipped, the MAF will arrest the increased boost pressure and the stuttering comes (boost cut feature).

Just picked up my 850 T5 which had stuttering at heavy acceleration and found split vacuum pipes. replaced them and problem solved. Goold ol' internet forums. :-)