Strong engine vibration at low speeds

Cerious

Member
Joined
Oct 9, 2008
Location
Windsor, ON Canada
TDI
99 A3 Jetta TDI
I lifted the hood and listened to my early 99 Jetta engine running for the first time in a while and was shocked at how much it was vibrating and it also seemed much noisier than usual. Took it to a mechanic and he found the front motor mount was broken and the driver side mount was weak. He replaced them but the vibration and noise problem isn't much better. I'm thinking that the vibration came first and caused an early failure of the motor mounts. Mileage has dropped from 55 miles per Imperial gallon to about 45. Car just passed 200,000 km. Have only used full synthetic oil designed for diesel engines. Power is good. Starts great. Engine light has been coming on but codes have been vague. Used to come on only during highway drives on hot days. Now it comes on in the winter. Engine noise seems regular (not missing). What are the most likely suspects for a car of this mileage.
 

ToddA1

Top Post Dawg
Joined
Aug 3, 2011
Location
NJ 08002
TDI
'96 B4V, '97 B4 (sold), '97 Jetta (scrapped)
When was the last time you checked your timing?

-Todd
 

bturpin

Veteran Member
Joined
Jun 25, 2014
Location
North Idaho
TDI
1998 Jetta mk3 TDI AHU
My car vibrated like mad before I started running cenex premium diesel fuel. Now vibrations are completly gone.
 

mojogoes

Top Post Dawg
Joined
May 1, 2003
Location
england
TDI
mk3 tdi golf
I lifted the hood and listened to my early 99 Jetta engine running for the first time in a while and was shocked at how much it was vibrating and it also seemed much noisier than usual. Took it to a mechanic and he found the front motor mount was broken and the driver side mount was weak. He replaced them but the vibration and noise problem isn't much better. I'm thinking that the vibration came first and caused an early failure of the motor mounts. Mileage has dropped from 55 miles per Imperial gallon to about 45. Car just passed 200,000 km. Have only used full synthetic oil designed for diesel engines. Power is good. Starts great. Engine light has been coming on but codes have been vague. Used to come on only during highway drives on hot days. Now it comes on in the winter. Engine noise seems regular (not missing). What are the most likely suspects for a car of this mileage.
For one i wouldn't run fully Syn in this engine.............I did once and the top end got pretty loud i didn't know what it was until i realised the oil was the only change from standard i'd done on this service.

Once we dropped the oil and put back some good old Castrol 15/40 semi syn it ran and sounded smooth again , could be one reason why its got noisey!!

Is the car / engine standard or have you got engine modifications (Name them!) if so? Has this motor had a +hammer mod done to it as this can cause the fuel pump to be noisier than usual and can make the car shake at idle.

What clutch has it got in it now has it recently had a new or different clutch or flywheel fitted? has this motor had any larger injectors fitted with out having had an ecu tune which can also make an engine shake at idle.

A general guess and intuitiveness on my part is that! i think you beat up on this car from time to time:) and although these motors are pretty bomb proof , if certain areas are not kept up to! this is the sort of thing which will plague you time and time again But we do need more info on the state of the cars tune.:)
 

Cerious

Member
Joined
Oct 9, 2008
Location
Windsor, ON Canada
TDI
99 A3 Jetta TDI
Engine shake

For one i wouldn't run fully Syn in this engine.............I did once and the top end got pretty loud i didn't know what it was until i realised the oil was the only change from standard i'd done on this service.

Once we dropped the oil and put back some good old Castrol 15/40 semi syn it ran and sounded smooth again , could be one reason why its got noisey!!

Is the car / engine standard or have you got engine modifications (Name them!) if so? Has this motor had a +hammer mod done to it as this can cause the fuel pump to be noisier than usual and can make the car shake at idle.

What clutch has it got in it now has it recently had a new or different clutch or flywheel fitted? has this motor had any larger injectors fitted with out having had an ecu tune which can also make an engine shake at idle.

A general guess and intuitiveness on my part is that! i think you beat up on this car from time to time:) and although these motors are pretty bomb proof , if certain areas are not kept up to! this is the sort of thing which will plague you time and time again But we do need more info on the state of the cars tune.:)
The engine and clutch are totally stock. I haven't beat it. I drive for mileage. Mostly I drive like a 90 year old. OK, I'll admit that once in a while I drive like a 70 year old but that's the extent of rough treatment that its had. Could you be projecting a wee bit?
 

GTiTDi

TDIClub Enthusiast, Macht Schnell! Vendor , w/Busi
Joined
Oct 18, 2010
Location
3 Spruce st Wareham, gateway to Cape Cod Massachus
TDI
'91 GTI CJAA swap,'02 Jetta wagon ALH swap, '03 GTI 1.8T rally car, '03 Sprinter 3500
The engine and clutch are totally stock. I haven't beat it. I drive for mileage. Mostly I drive like a 90 year old. OK, I'll admit that once in a while I drive like a 70 year old but that's the extent of rough treatment that its had. Could you be projecting a wee bit?
More than a wee bit.
 

WestVa304

TDIClub Contributor
Joined
Sep 16, 2010
Location
Ashevegas
TDI
2005 TDI Jetta Wagon, 2004 Passa Tdi 5spd
Have you replaced the vacuum lines? If not the ECM code is probably from the hose inside of it. The ECM is very easy to get to and replacing all of the lines is a very easy, cheap fix and it should be done as ten-twenty year maintenance anyhow lol. Paramedick has a great write up on the topic.

Also if you drive granny style most of the time it would be a good idea to check for soot buildup in the intake manifold. Not stretching out the rpms under load every once in a while compounds the buildup.

And when you check the timing also check the injection quantities and maf just to be safe.
 

mojogoes

Top Post Dawg
Joined
May 1, 2003
Location
england
TDI
mk3 tdi golf
The engine and clutch are totally stock. I haven't beat it. I drive for mileage. Mostly I drive like a 90 year old. OK, I'll admit that once in a while I drive like a 70 year old but that's the extent of rough treatment that its had. Could you be projecting a wee bit?

Did you really only want to address just the clutch point i made and forget the rest?

You crack on!! no doubt the car will be up and running a 100% in no time:rolleyes:
 
Top