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S80 '98-'06 / S60 '00-'09 / V70 & XC70 '00-'07 General Forum for the P2-platform S60 / V70 / XC70 / S80 models |
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v70 2.5T engine judders when acceleratingViews : 1381 Replies : 14Users Viewing This Thread : |
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Oct 13th, 2019, 13:53 | #11 |
Lazy Member
Last Online: Today 13:06
Join Date: Mar 2007
Location: HORLEY
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Hi.
Just a few questions.... Is your car auto or manual ? Does your car show symptoms when cold , when warm or both ? Does it have a fuel pressure sensor on the fuel rail ? Any mods on engine ? Has it shown symptoms since having work done ? |
Oct 13th, 2019, 14:41 | #12 |
Master Member
Last Online: Feb 28th, 2024 17:13
Join Date: Sep 2012
Location: Loughborough
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Diesel man myself, but having read quite a few threads on here............
What make of spark plugs are in there....just a guess. Your answer my well provoke some educated replies or may not.
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2008 V70 SE D5 Auto 185 ...now 205 Volvo Polestar......188k Passed away - 1999 V70 2.5tdi Auto 340632 miles, RIP. |
Oct 20th, 2019, 10:00 | #13 |
New Member
Last Online: Nov 12th, 2019 22:14
Join Date: Sep 2019
Location: peterborough
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Thanks Volvoboy...
It's an Auto engine. Seems worse the hotter the engine is. I can do a whole motorway journey with very gentle acceleration and won't notice it but as soon as I put engine under greater load or acceleration it will start to judder. If I drive hard it will get bad very quickly, but only when warm, and far worse when hot. Garage has replaced plugs and coil-packs. No difference on either occasion. Only codes ever shown was misfire on 2 x cylinders; that was when rpm actually decayed to zero after very heavy juddering/power-loss. Car was ok but fragile after 10 mins leaving engine off. That's when garage replaced coil packs to the 2 cylinders that had the codes, but no difference; although car hasn't actually broken down again to be fair...
No mods on engine and don't know if has fuel pressure sensor on fuel rail I'm afraid, but many thanks for the post...I'm stuck... |
Oct 20th, 2019, 14:52 | #14 |
Lazy Member
Last Online: Today 13:06
Join Date: Mar 2007
Location: HORLEY
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Hi.
If it`s not a misfire due to electrics then it must be fuel/air related. What was the condition of the old plugs - weak on fuel - I wonder ? On warm-up the engine management is demanding extra fuel . That may make a misfire less noticeable .When hot the fuel trim is lower , possibly to the point of being almost weak. So when you make a heavy demand ( flooring the throttle / lugging the engine) there`s a misfire. It doesn`t sound like a vacuum leak as high vacuum is at idle / light load and you say the car seems OK then. It could be an induction pipework leak which would cause weak running .The engine management will try to compensate as much as possible. If there is a fuel pressure sensor on the end of the fuel rail it could be faulty. They are a known problem on earlier petrol P2`s. Also there is a fuel pressure regulator mounted with the fuel-pump. These can fail. Later P2`s have a fuel pressure control module . This can be affected by water ingress and corrosion. I would check this area first. If it`s not ignition and it`s not fuel and it`s not air leaks then move on to other areas such as turbo, engine earth-leads or the engine management. Keep us posted. |
Nov 12th, 2019, 22:14 | #15 |
New Member
Last Online: Nov 12th, 2019 22:14
Join Date: Sep 2019
Location: peterborough
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Thanks so much for the comprehensive advice Volvoboy. I'm no mechanic so I'm gonna take your advice to my local garage and see what they can possibly do. You've been most helpful - i'll let you know how things turn out...
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