Engine 850: B5234T/2.3/20v/T5: - missfire 3k

t5monster · Oct 4th, 2009, 12:05

i have just had a clutch changed as it was dead and since having it returned am having the problem when under full throtle of a slight missfire and then it picks back up.

before i had the clutch done i could feel it happening but it did not affect the engine as much as the clutch didnt lock like it was meant to now when accelarateing between 3k-3.5 k i feel it struggling to boost and also loses boost before picking back up.

i have changed the plugs rotor arm and dist cap which i thought was the prob as the rotor had cracking down the sealent on arm and the cap had a little crack and 2 plugs had cracks on the ceramic around plugs i have checked for boost leaks and am now lost on what to do next the car is running on 1 bar boost and the problem comes when it hits about 0.8 bar boost then judders and then goes if i do not full throttle it doesnt happen but am starting to think its the head gasket blowing accross 2 pistons when it gets high pressure in chamber any help appreiciated

capt jack · Oct 4th, 2009, 13:54

Plug leads could be at fault - it's the one component in the ignition you've not changed.

Halfords do a set for around £40, but there will be other suppliers no doubt.

Cheers

Jack

t5monster · Oct 4th, 2009, 16:51

had a price from gsf and they 36 quid however i took it up the motorway and doesnt do it in 4th and 5th then stopped alltogether then came back again also i need a new pcv system as the pipes have broken and vents into the air but think it may be causeing this as theres a huge area of oil thats sprayed out like its been blocked then cleared so will change that soon and go from there thanks anyway

foggyjames · Oct 4th, 2009, 18:11

It is a rapid stuttering misfire? If so, it's almost certainly ignition. You've gone the plugs, cap and rotor...so I'd look at the leads and coil.

If the miss is "slower"...start looking at the fuel/engine management side of things.

cheers

James

Jod T5 · Oct 4th, 2009, 18:28

i would check the plug gaps and the inlet manifold vacuum elbow....

Jod

t5monster · Oct 6th, 2009, 09:55

the vacuum is ok on the car as i have a boost gauge fitted and on tickover its pulling the normal .8 which i belive is correct there is definately no boost leaks im starting to think it could be leads or a dodgy rotor arm or cap i have fitted the problem was there with the old but as said could be the leads its also started doing it more now when the boost reaches 1 bar and judders like a missfire then loses boost then picks up and does it again also it only does it on full open throttle and not atall when using minor throttle.

trying to get some 2nd hand leads to try before i spend more money out that i dont have at the mo will update shortly also wasnt sure if could be fuel pump or an injector thats also causing it

t5monster · Oct 6th, 2009, 16:49

went to my local scrap yard and found a set of 850 20 valve leads altho they are not off a turbo they are the budgiecord ones and off the same engine and this has fixed the problem it feels very much more responsive and also has alot better boost and is pushing 1.3 overboost dieing to 1 bar in 4th and 5th so am happy with the end results thanks for all the help and advice thats been given

foggyjames · Oct 6th, 2009, 22:35

Told ya a "fast" juddering misfire would most likely be ignition

Glad you got it sorted

cheers

James

Oct 4th, 2009, 12:05	#1
t5monster Senior Member Last Online: Feb 25th, 2012 11:14 Join Date: Sep 2009 Location: portsmouth	missfire 3k i have just had a clutch changed as it was dead and since having it returned am having the problem when under full throtle of a slight missfire and then it picks back up. before i had the clutch done i could feel it happening but it did not affect the engine as much as the clutch didnt lock like it was meant to now when accelarateing between 3k-3.5 k i feel it struggling to boost and also loses boost before picking back up. i have changed the plugs rotor arm and dist cap which i thought was the prob as the rotor had cracking down the sealent on arm and the cap had a little crack and 2 plugs had cracks on the ceramic around plugs i have checked for boost leaks and am now lost on what to do next the car is running on 1 bar boost and the problem comes when it hits about 0.8 bar boost then judders and then goes if i do not full throttle it doesnt happen but am starting to think its the head gasket blowing accross 2 pistons when it gets high pressure in chamber any help appreiciated

Oct 4th, 2009, 18:11	#4
foggyjames 300 Register Keeper Last Online: May 7th, 2024 11:06 Join Date: Dec 2001 Location: Nottingham	It is a rapid stuttering misfire? If so, it's almost certainly ignition. You've gone the plugs, cap and rotor...so I'd look at the leads and coil. If the miss is "slower"...start looking at the fuel/engine management side of things. cheers James __________________ VOC 300-series Register Keeper '13 V70 D4 SE Lux '89 740 Turbo Intercooler '88 360 Turbo Intercooler '84 360 GLT '81 343 GLS R-Sport '79 343 DL '70 164

Oct 4th, 2009, 18:28	#5
Jod T5 Phoenix from the ashes Last Online: Apr 24th, 2024 01:05 Join Date: Jan 2006 Location: Finchingfield	i would check the plug gaps and the inlet manifold vacuum elbow.... Jod __________________ Dum Spiro Spero VOC 20419

Oct 6th, 2009, 22:35	#8
foggyjames 300 Register Keeper Last Online: May 7th, 2024 11:06 Join Date: Dec 2001 Location: Nottingham	Told ya a "fast" juddering misfire would most likely be ignition Glad you got it sorted cheers James __________________ VOC 300-series Register Keeper '13 V70 D4 SE Lux '89 740 Turbo Intercooler '88 360 Turbo Intercooler '84 360 GLT '81 343 GLS R-Sport '79 343 DL '70 164

Oct 4th, 2009, 13:54	#2
capt jack VOC Member Last Online: Yesterday 20:44 Join Date: Jun 2006 Location: Selby, North Yorkshire	Plug leads could be at fault - it's the one component in the ignition you've not changed. Halfords do a set for around £40, but there will be other suppliers no doubt. Cheers Jack

Oct 4th, 2009, 16:51	#3
t5monster Senior Member Last Online: Feb 25th, 2012 11:14 Join Date: Sep 2009 Location: portsmouth	had a price from gsf and they 36 quid however i took it up the motorway and doesnt do it in 4th and 5th then stopped alltogether then came back again also i need a new pcv system as the pipes have broken and vents into the air but think it may be causeing this as theres a huge area of oil thats sprayed out like its been blocked then cleared so will change that soon and go from there thanks anyway

Oct 6th, 2009, 09:55	#6
t5monster Senior Member Last Online: Feb 25th, 2012 11:14 Join Date: Sep 2009 Location: portsmouth	the vacuum is ok on the car as i have a boost gauge fitted and on tickover its pulling the normal .8 which i belive is correct there is definately no boost leaks im starting to think it could be leads or a dodgy rotor arm or cap i have fitted the problem was there with the old but as said could be the leads its also started doing it more now when the boost reaches 1 bar and judders like a missfire then loses boost then picks up and does it again also it only does it on full open throttle and not atall when using minor throttle. trying to get some 2nd hand leads to try before i spend more money out that i dont have at the mo will update shortly also wasnt sure if could be fuel pump or an injector thats also causing it

Oct 6th, 2009, 16:49	#7
t5monster Senior Member Last Online: Feb 25th, 2012 11:14 Join Date: Sep 2009 Location: portsmouth	went to my local scrap yard and found a set of 850 20 valve leads altho they are not off a turbo they are the budgiecord ones and off the same engine and this has fixed the problem it feels very much more responsive and also has alot better boost and is pushing 1.3 overboost dieing to 1 bar in 4th and 5th so am happy with the end results thanks for all the help and advice thats been given

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