Sudden engine vibration under acceleration

BGA · Oct 16th, 2015, 10:24

V70-99, 170hp, man. transm.
Car and engine was running nice in the evening. Next morning engine was vibrating hard under acceleration, but just under acceleration. No engine light has shown. This started less then a week ago. So far has only added a bottle of injector cleaner. What shall I more look for?
Car is with my daughter living 600 km away, so I havent driven it myself and been able to read OBD.
Seaching this and other Volvo forums gives engine mounts first thing to check. Second is injectors. Needs cleaning and checking connectors. But can these problems come suddenly, over night?

Thanks

Luxobarge · Oct 16th, 2015, 10:46

Check the engine mounting rubber bushes - favourite is the top one that goes from the rear left of the engine to the bulkhead, but check the ones at the bottom too.

What sort of vibration is it? It could also be a misfire, if so then you need to sort it pronto because if you drive the car with a misfire you stand a very good chance of toasting the catalytic converter. On your car you have individual coils for each cylinder rather than a conventional distributor, and these can and do fail, causing misfire - this can happen only under acceleration too.

brickman · Oct 17th, 2015, 09:24

Driveshaft or support bearing let go?

BGA · Oct 17th, 2015, 11:39

I will check rubber mountings. Depending on design I can understand they can give up suddenly.

Shouldn't a misfire switch the engine lamp on?

Driveshafts and support bearing was renewed a year ago and inspected (our MOT) some weeks ago.
Bad joints are noisy when taking a corner and are wheel speed depending.
A bad support bearing is noisy all time and depending on wheel speed.

BGA · Oct 18th, 2015, 11:40

It was a coil. Disconnected them one by one and found the not working cylinder. Than shifted that coil to another cylinder and the failure followed the coil!
Need to drive a few km with the bad coil - do you recommend me to disconnect the injector on that not firing cylinder?

Luxobarge · Oct 18th, 2015, 12:20

Great! Glad you found the problem - nice one. Remember that if one coil goes others may not be far behind, so if you can afford it I'd recommend either replacing all of them or as a compromise buying two, and keping one as a spare.

You really shouldn't drive it at all like that, because as well as unburnt fuel going through the system and igniting in the cat, the block will also heat up unevenly and might cause problems. However, if you insist then yes, I guess disconnecting the injector will help - otherwise the fuel can also wash the oil off the bore and cause rapid wear too, as well as causing catalytic converter problems.

Hope all goes well - let us know when it's fixed eh?

Cheers!

BGA · Nov 3rd, 2015, 10:08

My son in law drove to the local scrapyard and bought a coil for 200 krona ~
20£. Last week they drove 1500 km - no problem.
Tank you all!
Cheers!

Oct 16th, 2015, 10:24	#1
BGA Junior Member Last Online: Oct 12th, 2021 10:18 Join Date: Dec 2008 Location: Kagerod, Sweden	Sudden engine vibration under acceleration V70-99, 170hp, man. transm. Car and engine was running nice in the evening. Next morning engine was vibrating hard under acceleration, but just under acceleration. No engine light has shown. This started less then a week ago. So far has only added a bottle of injector cleaner. What shall I more look for? Car is with my daughter living 600 km away, so I havent driven it myself and been able to read OBD. Seaching this and other Volvo forums gives engine mounts first thing to check. Second is injectors. Needs cleaning and checking connectors. But can these problems come suddenly, over night? Thanks

Oct 16th, 2015, 10:46	#2
Luxobarge Premier Member Last Online: Today 08:29 Join Date: Jan 2011 Location: Horne (Nr. Horley)	Check the engine mounting rubber bushes - favourite is the top one that goes from the rear left of the engine to the bulkhead, but check the ones at the bottom too. What sort of vibration is it? It could also be a misfire, if so then you need to sort it pronto because if you drive the car with a misfire you stand a very good chance of toasting the catalytic converter. On your car you have individual coils for each cylinder rather than a conventional distributor, and these can and do fail, causing misfire - this can happen only under acceleration too. __________________ Some people are like Slinkies, they serve no useful purpose but they still bring a smile to your face when you push them downstairs.

Oct 17th, 2015, 09:24	#3
brickman Premier Member Last Online: May 31st, 2024 15:50 Join Date: Jul 2013 Location: Glasgow	Driveshaft or support bearing let go? __________________

Oct 18th, 2015, 12:20	#6
Luxobarge Premier Member Last Online: Today 08:29 Join Date: Jan 2011 Location: Horne (Nr. Horley)	Great! Glad you found the problem - nice one. Remember that if one coil goes others may not be far behind, so if you can afford it I'd recommend either replacing all of them or as a compromise buying two, and keping one as a spare. You really shouldn't drive it at all like that, because as well as unburnt fuel going through the system and igniting in the cat, the block will also heat up unevenly and might cause problems. However, if you insist then yes, I guess disconnecting the injector will help - otherwise the fuel can also wash the oil off the bore and cause rapid wear too, as well as causing catalytic converter problems. Hope all goes well - let us know when it's fixed eh? Cheers! __________________ Some people are like Slinkies, they serve no useful purpose but they still bring a smile to your face when you push them downstairs.

Oct 17th, 2015, 11:39	#4
BGA Junior Member Last Online: Oct 12th, 2021 10:18 Join Date: Dec 2008 Location: Kagerod, Sweden	I will check rubber mountings. Depending on design I can understand they can give up suddenly. Shouldn't a misfire switch the engine lamp on? Driveshafts and support bearing was renewed a year ago and inspected (our MOT) some weeks ago. Bad joints are noisy when taking a corner and are wheel speed depending. A bad support bearing is noisy all time and depending on wheel speed.

Oct 18th, 2015, 11:40	#5
BGA Junior Member Last Online: Oct 12th, 2021 10:18 Join Date: Dec 2008 Location: Kagerod, Sweden	It was a coil. Disconnected them one by one and found the not working cylinder. Than shifted that coil to another cylinder and the failure followed the coil! Need to drive a few km with the bad coil - do you recommend me to disconnect the injector on that not firing cylinder?

Nov 3rd, 2015, 10:08	#7
BGA Junior Member Last Online: Oct 12th, 2021 10:18 Join Date: Dec 2008 Location: Kagerod, Sweden	My son in law drove to the local scrapyard and bought a coil for 200 krona ~ 20£. Last week they drove 1500 km - no problem. Tank you all! Cheers!

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