Sounds 'tappety' under load

[Jaye R]

Chaps - your thoughts please...

I don't know whether it's just me, but, when unload (accelating) the car sounds 'tappety' - nothing major, just not a 'smooth' sound

I have checked the timing & this is fine - sits at 12 degrees when warm & idle & no 'tappety' noise which would indicate the timing is out.

The car does not sound like this when you rev it when stationary - it only occurs when accelating (hard or soft accelaration).

Is this just me & this is the normal sound of a V6 - I can't seem to remember back to last year as to whether it sounded this way.

Any thoughts/suggestions would be appreciated.

Other than this, car is running beautifully.

Cheers
Jaye

[DonkeyApple]

Jaye R said:

Chaps - your thoughts please...

I don't know whether it's just me, but, when unload (accelating) the car sounds 'tappety' - nothing major, just not a 'smooth' sound

I have checked the timing & this is fine - sits at 12 degrees when warm & idle & no 'tappety' noise which would indicate the timing is out.

The car does not sound like this when you rev it when stationary - it only occurs when accelating (hard or soft accelaration).

Is this just me & this is the normal sound of a V6 - I can't seem to remember back to last year as to whether it sounded this way.

Any thoughts/suggestions would be appreciated.

Other than this, car is running beautifully.

Cheers
Jaye

Pinking?

[Jaye R]

Possibly - what does 'pinking' suggest - sorry, not up on 'technical speak'?

Cheers
Jaye

[ketvrin]

Hi Jaye

when accelerating perhaps you are hearing a "rattle" that makes you think "Tappety" ? pesumably its from the front end but could it be something rattling or being lightly hit as the engine moves around under load and any gaps become insufficient?
exhaust on chassis ?
ARB on sump?
Anything metallic touching a rocker box ? Hose clip etc...

look for "witness" marks...

K

Edited by ketvrin on Wednesday 5th May 10:27

[Jaye R]

Kev

Could be - will check things over this weekend. I'm just hoping the noise isn't the cound of something 'going wrong' somewhere.

If I don't find anything, maybe, you guys can have a listen on the way down to SCH & we can have a 'identify the noise' competition when we get down there

Cheers
Jaye

[DonkeyApple]

Jaye R said:

Possibly - what does 'pinking' suggest - sorry, not up on 'technical speak'?

Cheers
Jaye

Someone else can give far more info but in layman terms if the ignition is slightly too advanced then you get pre-detonation in the heads when the engine is under heavy load. It certainly isn't uncommon.

It sounds like a strong, rapid, rattle at the top of the engine. It is quite distinct.

The usual cause is not actually wrong timing per se but different fuels. Where one fuel may be perfect for the current timing set-up another may be weaker and mean that the timing is fractionally too advanced.

Retarding the ignition a little will solve the problem but lose you a little bit of response and power but is generally the quick fix.

I'm sure many other Phers can give better details.

[itiejim]

Could be just a leak on one of the exhaust headers.

[Jed-S]

Jaye R said:

I have checked the timing & this is fine - sits at 12 degrees when warm & idle & no 'tappety' noise which would indicate the timing is out.

Did you place it in service mode though when you checked it? Removing the throttle pot cable to attempt to place it into service mode never works reliably for me so I always place the ECU into service mode.

[phillpot]

[quote=Jed-S
I always place the ECU into service mode.
[/quote]

How do you do that please?

Going back to the noise I'd second the blowing exhaust theory, maybe one (or more0 of the manifold to head gaskets ?

Edited by phillpot on Wednesday 5th May 11:15

[Jaye R]

Jed-S said:

Jaye R said:

I have checked the timing & this is fine - sits at 12 degrees when warm & idle & no 'tappety' noise which would indicate the timing is out.

Did you place it in service mode though when you checked it? Removing the throttle pot cable to attempt to place it into service mode never works reliably for me so I always place the ECU into service mode.

Jed - I'd ask the same - how do I put the ECU in to service mode.

Plan is to start with Kev's suggestion and make sure nothing is rattling in the engine bay, then/and make sure all the manifold to head bolts are tight (as the manifold gaskets were replaced over the winter), then if all that doesn't work I will go down the 'service mode' route.

Many thanks for all the helpful suggestions - looking forward to a nice Sunday of 'playing about'

Cheers
Jaye

[Wildfire]

Could be a leaking exhaust manifold gasket. They tend to make aticking sound when leaking. Listen down a tube to try and locate it.

[tvrgit]

I would go with Itiejim and Wildfire - a leaking exhaust manifold gasket can sound exactly like a tappet. Mine was doing this just the other week and I found two of the manifold bolts slightly loose. Tightened them up, noise went away.

[MnS]

Same goes Jaye, a blowing exhaust gasket does have similar sound, had a sheared exhaust manifold bolt on the 'M' which i sorted over the winter, it sounded very tappety(more agricultural actually)and was all set to do them but once the bolt was removed and new gaskets fitted engine sounds sweet - one less job to do. Try and give them all a bit of a nip up may be all it is.
Ian

[Stew Mc]

If you think you have an exhaust blow but are not sure, have the engine running at idle and get a friend to hold a couple of rags over the tail pipes. The increase in pressure will force the spent gas out of any place blowing. If you have your head under the bonnet, you should be able to hear it.
The tail pipes can get a bit warm though so a pair of old gloves may help. Tell-tail black soot around the blow is also a good indicator.
Stew.

[mep12345]

This may sound silly, but a stethoscope or a funnel and piece of tubing (improvised stethoscope) can help you track it down as you move it around areas near to the potential blow sites it will amplify any noise (do not touch the engine etc or it will drown any blow noise)

[Jed-S]

Jaye R said:

Jed - I'd ask the same - how do I put the ECU in to service mode.

You'll need a Fault Code Reader which is not much more than a switch and a LED IIRC. Ebay item 300354017572 is the 5 pin one that most S2/S3 seem to use. In the mass of wiring in the passenger foot well is a connector that the unit plugs in to. Then it is a case of setting teh switch on the unit in the correct position and starting the car. You have to press the throttle all the way at some point when prompted and after a min or so the ECU drops into service mode and that is when you need to time teh ignition. It is all explained in the manual that comes with the unit.

As I said, I've not had reliable results by just disconnecting the TPS so that is why I always use the FCR ( I actually have a better one as well but that's another story). There is apparently another option to get into service mode but I've not tried it so won't print it here.

Jed

Edit: I also would suspect a leaking manifold but would have thought you'd hear it at idle as well. I find that the leaks sound worse at idle than when under load.

Edited by Jed-S on Wednesday 5th May 20:14

[Jaye R]

Chaps

Have checked all the manifold bolts & all tight. Not tried doing the timing whilst the ECU is in service mode.

I did, however, notice this residue (white 'powdery' type) on the manifold down pipe - could this have something to do with it? Do I have a slight hole in downpipe?



Many thanks

Cheers
Jaye

[Jaye R]

Jed-S said:

Jaye R said:

Jed - I'd ask the same - how do I put the ECU in to service mode.

You'll need a Fault Code Reader which is not much more than a switch and a LED IIRC. Ebay item 300354017572 is the 5 pin one that most S2/S3 seem to use. In the mass of wiring in the passenger foot well is a connector that the unit plugs in to. Then it is a case of setting teh switch on the unit in the correct position and starting the car. You have to press the throttle all the way at some point when prompted and after a min or so the ECU drops into service mode and that is when you need to time teh ignition. It is all explained in the manual that comes with the unit.

As I said, I've not had reliable results by just disconnecting the TPS so that is why I always use the FCR ( I actually have a better one as well but that's another story). There is apparently another option to get into service mode but I've not tried it so won't print it here.

Jed

Edit: I also would suspect a leaking manifold but would have thought you'd hear it at idle as well. I find that the leaks sound worse at idle than when under load.

Edited by Jed-S on Wednesday 5th May 20:14

Jed

I can't seem to find a 'pin socket' under the dash in the passenger footwell. Don't suppose anyone has a photo of what it looks like & where to find it. Is it on/near the fuses??

I have disconnected the TP and the revs increase (changing the timing up towards 6 degrees) - should this happen & should I adjust the timing back to 12 degrees when the TP is disconnected?

The car also smells (under normal idle) as if it running rich (it only just passed it's emmissions test on the MOT last month)- could this all be linked?

Many thanks in advance of your advises.

Cheers
Jaye

[ketvrin]

Hi Jaye

Its the black one here next to the red and black one (which is the Octane Adjustment - which you might also want to consider depending on what fuel you are running - unleaded or V-power...?)



K

[Jaye R]

Kev

Thanks - will take a look. I can't see that I need to adjust the octane - as I've always used unleaded and it's never run rich before???

Cheers
Jaye