Freelander 1 Vibration at Idle - Voltage linked!?! - SOLVED !!!

Having just changed the alternator - see another thread ! All is working well except engine has noise and vibration at idle. Take revs to 900 and all is well. Checking out threads I'm thinking fuel rail pressure - but has anyone had this problem appear after increasing voltage. New alternator takes battery to 14.6 v where as cab monitor display (self fitted) only showed 14.2 v on a good day before !

Will clean connector on fuel rail - any other ideas please?

Thanks.........

Is the more powerful alternator making the bottom pulley slip on its laminations? That's the most common cause of vibrations at idle.

Thanks, it crossed my mind too. Pulley was replaced around 12 months ago and I must admit when I put the snake belt back on I thought - hope I don't upset the pulley !!! How to test pulley?? If I remove belt again and hence remove load it should go clear? I have tried the opposite - easier to do - put max electrical load on and see if it gets worse, but it doesn't. No signs of dust, but it is a fairly new pulley and may have just started. It felt solid, but then so did the last one and it made the car sound like a traction engine !

To check the pulley. Put a dab of Tippex on the inner and outer metallic sections in line with each other. Then run the engine for a short period. Then see if the marks have moved in relation to each other.

Tried the pulley test and all seems fine, it runs true, noise doesn't seem to come from pulley although I can see that the whole engine vibrating could come from the pulley. Pulley has done 30k miles. Checked and cleaned fuel rail sensor connections. Checked live data and only change I can see is high pressure rail is down from 28600 kpa to 27600 kpa this is about 145psi drop I think. Car drives well and pulls well. My gut is telling me that it must be the pulley again. Last time it clanged and rattled, but this time............... I'm thinking of dropping belt off and testing without the load on it - maybe not slipping (as per the test) but minor wobble???

Dunno, hate faults like this, would rather it didn't run - but don't quote me !

I'm wondering if the alternator is taking more power from the crank than the EDC is expecting. I think the EDC learns the idle characteristics, which the new alternator has changed.
It could take a few miles to relearn the new idle characteristics.
You've checked the pulley, so there's little else it can be.

Yes this could be the issue, although I wouldn't expect a new alternator (with a set load) to take more grunt than an old one with same load? If anything the old one would have been stiffer - bearings etc.
I will watch and see what happens over the next 50 miles then do the belt drop test ! (sounds risky!) and see what happens then.
Thanks for your help so far ! Didn't know the EDC part of the EMS was so intelligent !

andyfreelandy said:

Yes this could be the issue, although I wouldn't expect a new alternator (with a set load) to take more grunt than an old one with same load? If anything the old one would have been stiffer - bearings etc.
I will watch and see what happens over the next 50 miles then do the belt drop test ! (sounds risky!) and see what happens then.
Thanks for your help so far ! Didn't know the EDC part of the EMS was so intelligent !

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The old alternator probably wasn't taking as my torque to spin it as the new one is. Bearings get looser with time, as they run in.
Brushes also wear down and the slip ring recedes, reducing mechanical drag on the comutator. Also as brush pressure reduces, the low speed output also reduces. Reduced output means less power to turn it.

As far as I know, the Bosch EDC used in the FL1 is advanced enough to be adaptive, and should calibrate itself to compensate of loads imposed on the engine.

In an attempt to hope that "it goes away all on its own!" - I have now covered a 100 miles or more and the vibration is getting worse !
So - checked on problems with the supplier over any issues with the pulley I bought - it has a 2 year guarantee - not a brill response !
Hi thanks for your email but we are sorry to say that due to the high volume of emails we are receiving can not reply to you , please do not reply to this email.
So - not having that I thought and called them - apparently the 2 year guarantee has been changed to 1 year - mine is out ! and returning reported dodgy ones to the factory to test has concluded "it is a high mileage engine fault - not the pulley!"

so - bit stuck, may buy a new (cheap pulley) just to eliminate (unless anyone has a loan spare in good order) - may remove each injector electrical feed to see if there is an injector problem that just happened to show after a new alternator fitted !!
Leak back test? Speed tickover up to 900 rpm so that it stops ! Getting desperate - sounds like it is going to take off when idling - up to 900rpm, drives fine.

Any more ideas please??

Start it with the alternator belt removed and see what happens.

So - parked my 2 TD4's next to each other, ran them, used my mechanics (tube) stethoscope and listened to water pump, a/c, hp pump and then alternator. The new alternator sounds like a steam hammer and the other one sounds (like I would expect) a high pitched scream.

So - not solved the 'why' but it looks like another 4 hours lying on my back (not in a good way !) - have contacted supplier - will inform thread. Thanks for all help and suggestions.

So if you run it with the alternator belt off, does the engine run smooth?

Job for tomorrow to check - but I am confident that the alternator is to blame. I am first making a belt tensioner spanner 'not slipper offer' to make sure that I don't loose a finger when removing and replacing belt !!! Something to make sure that the spanner is held on and up against the very thin nut on the tensioner. Cheers

andyfreelandy said:

Job for tomorrow to check - but I am confident that the alternator is to blame. I am first making a belt tensioner spanner 'not slipper offer' to make sure that I don't loose a finger when removing and replacing belt !!! Something to make sure that the spanner is held on and up against the very thin nut on the tensioner. Cheers

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24mm ring spanner with the tapered lead-in ground off. Fit to nut, then wedge in a piece of wood or a Halford’s 1/2” ratchet handle against the inner wing. Lock in another spanner’s ring into the open end to give more leverage and move your hands further from harm.

If your tensioner is really that stiff, and while you have stuff off, consider removing it and cleaning up/copper greasing the shaft that goes into the timing cover. Our last Td4 had such a tight tensioner that when the spanner slipped off (before I’d developed the method above) my thumb hit the radiator so hard the nail split lengthways down to the quick.

Thanks and ouch GF ! Budding car mechanics should have all their finger nails removed at birth to prevent such pain later in life !!
That is why I left it until today to make a slim piece of wood to slide over the spanner head and hold all firm. It is not that stiff to turn, just a bit of a tricky manouvre that needs all the help it can get. Still waiting to hear from alternator supplier - they have confirmed receipt of fault.

So - fings is not always as they seems !
Noise was on alternator - yes.
Alternator quiet to the spin so - looked hard, 2 bolts missing from alternator mount on engine and one sheared off ! Dunno how long it has been like this.
*** of a job, but removed broken thread, replaced all bolts (allen) and all quiet.
Bracket wasn't loose to the touch, but all engine vibration transferred to the alternator due to marginal looseness !!!
Arggghhhhhhhhh

My 'spanner non slipper' for the belt tensioner works ( as a prototype) - piece of wood routed out to hang over spanner head and keep it pressed in against the chassis. Maybe going to work one in nylon which then doesn't try and escape turn due to friction and fall out.