Not running smooth anymore
 

Hi all

I have noticed recently that my 2ltr Diesel engine is vibrating. Perhaps the best way to discribe it would be to say it feels like it is running on 3 cylinders. It is most noticable with the auto in 'N' and rev the engine to just above 2000 rpm. It's rocking the car (engine seems out of balance and not smooth). I do not have a problem starting, or accelerating etc. I don't notice anything when traveling at 70mph when @2000rpm, or any other speed for that matter. It is most noticable when not under load, sometimes at lights when idling I see the rev counter slightly jumping, and not running smoothly (kinda chuggin).

Anyone have similar problem or any ideas what's causing this?

I've heard that loosening and then re-torquing the engine mount bolts can solve vibrations such as this. As you suggest it does it only when in neutral and not-moving I would discount vibrations from wheel-inbalance and suspension problems.

The revs may be just the right harmonic frequency to cause the block to resonate on it's mounts. I'd check these if I were you first. :lol:

Hmm the engine mount bolts eh. Are these easy to get at? Been a complete novice and all....

To be honest, I wouldn't know as I've not needed to re-torque mine. Best bet is to buy yourself a copy of the Haynes manual (don't forget you get a discount if you say your a member of this club) and buy yourself a propper torque wrench.

Hopefully the Hayne's manual will give you details on the location of said bolts and the correct torque at which they should be tightened to.

Worth hanging around on this thread for a bit though as someone may know this info already... If not, I'll go and prod someone to see if they can help!

You know something, the vibration isn't that noticable today. In fact I was slowly reving it when I got to work this morning and I didn't notice it happening at all. Then I noticed it a little this evening when I got home. :whip:

I am starting to notice that this car will behave differently from time to time. Perhaps I should stop worrying until something goes 'clunk'. I notice some people worry about the temp guage but sometimes mine it dead on half way (but rarely) and more often it is between a quater and half way.

I also notice that my fan only comes on every 30 secs or so for about 5 secs, then goes off.

Don't know what others think but the car runs great and fuel economy is good and as I don't have about 2K to give to my local garage to fix, I'll not worry too much. :)

Your fans broke.

No seriously. You have just described the all-time classic symptom of a failed radiator fan. :(

Give me a moment to point you in the right direction...

Right, I've asked someone to come along so hopefuly they (or someone else) will pop along and diagnose your radiator fan a bit more clearly. :lol:

If the fan is stop starting with the aircon on then most likely the low and medium speeds have failed

The Trinary switch in the aircon is then running it at high speed in response to an increase in refrigerant pressure once pressure drops fan stops this stop start behaviour will because of the current drawn also cause a momentary dip in the idle speed.

If you fancy the 70 Mile drive over here at the weekend I can put your car on Testbook and test it but if you have a local dealer they can do the same and it shouldn't cost you more than half an hours labour.

What year and mileage is your car?

Thanks for that Simon.

Hi Keith, the car is 02 and has (thinking....) about 78000 on the clock.

At the moment I have the 'econ' button working the heating. So the fan isn't and issue, and you are right what you say about a slight drop when the fan kicks in. To be honest, I've just bought 4 new tyres, had a full service and the rear wheel bearing done just a month ago and only had the car 5 months (Oh and tax is due at the end of the month). I really could do without spending any more on the car this time of year. Do you think this could wait until spring, as I don't use the aircon during the winter months? If it is a quick fix or something not too expensive then maybe I can do something, but I have no drive and have to park the car in the next street. So you see, I am very limited to what I can do on my own.

Thanks for the offer of Testbook BTW. :)

I was having a nosey through the 'other' forum the other night and noticed some talk about having a meet for a weekend while everyone fixes their 75s. Not sure if this was you Keith or was it someone else. There was talk of camping and all sorts. This would be a great idea for the likes of me...

Anyhow, there's my story so far.....

Oh, just remembered that I am visiting a friend in Shropshire on the 20th Dec. Is this any good for having a look with Testbook?

Maf sensor can also cause this.

Try disconnecting the plug.

Mine doesn't vibrate in neutral but I can produce a mild but audible chuga chuga below 18-2000rpm if I have the maf comp setting on my Synergy in correctly set.

Ron