Noise Coming From Engine At Around 2500 Revs

Call the midlife! · August 29, 2020, 18:41

Re the blob of sealant on the cylinder head. Where the timing chain cover meets the head there's a very slight difference in heights at the joint so the OEM standard instructions call for a small bead of sealant at this point on either side before fitting the cam cover and seal.
Technically it only needs doing if the previous sealant has been removed, on a rebuild for example, it could be that someone has got a bit carried away fitting the cam cover and put a big dollop on.

shnazzle · August 29, 2020, 21:45

You'd expect both short terms to fluctuate. That's kind of their thing.
But long-term you'd want close to 0.

I'm not sure what values you're reading on those F/T but values of 81 are definitely not right. A) it's not possible and B) they're calculated values so if it was 81 and ignoring A, it would be adding 81% more fuel in for that area and definitely be throwing an error code .. Unlikely. Methinks you've got the wrong PID selected.

You want "Fuel Trim Long Term" for bank 1 and 2

Erudite · August 30, 2020, 14:20

QuoteYou'd expect both short terms to fluctuate. That's kind of their thing.
But long-term you'd want close to 0.

I'm not sure what values you're reading on those F/T but values of 81 are definitely not right. A) it's not possible and B) they're calculated values so if it was 81 and ignoring A, it would be adding 81% more fuel in for that area and definitely be throwing an error code .. Unlikely. Methinks you've got the wrong PID selected.

You want "Fuel Trim Long Term" for bank 1 and 2

I think you were right. I've used another app and the data seems to be more accurate.

At idle.

At ~2000 revs.

shnazzle · August 30, 2020, 14:58

That's better.
Could have a look at bank2 (cylinders 2 and 4) but all in all it's all still well within acceptable ranges

Erudite · September 12, 2020, 17:52

Thanks @shnazzle much appreciated.

I've been out in it today and there's a loud noise coming from the engine at around 2500 revs (this is the sweet spot for it anyway).

The noise seems to occur after the car has been running for a while and when it's accelerating. Its even more pronounced when taking your foot off the accelerator.

I've tried to get a video of the noise here, quite difficult due to wind noise:

https://streamable.com/c4jjlg

I've checked the exhaust and the only heat shield that's at all lose is the one in the video below.

https://streamable.com/qz2fs1

I don't think that it's this causing the noise as it only catches very slightly on the surrounding metalwork and it's clear of the exhaust.

Any other ideas as to what it might be?

Carolyn · September 12, 2020, 18:09

Youtube vids of rattles and noises are invariably useless! At least you tried.

Time to get your car in front of an educated ear!

Question -does it make the noise when in neutral sitting still? If not -it's probably not coming from the engine itself.

there are ways of pinning these things down..

Erudite · September 12, 2020, 18:14

Quote from: Carolyn on September 12, 2020, 18:09Youtube vids of rattles and noises are invariably useless! At least you tried.

Time to get your car in front of an educated ear!

Question -does it make the noise when in neutral sitting still? If not -it's probably not coming from the engine itself.

there are ways of pinning these things down..

Only at around 2500 revs, I'm not sure if it's just at that point or if that's when it's most pronounced. Once you accelerate past 2500 revs or let it drop below the noise tails off. It's very loud at this point though and can be heard of the engine/exhaust. It sounds like a reverberation in my opinion.

If it's in neutral sitting still the noise can't be heard.

Carolyn · September 12, 2020, 18:18

Quote from: Erudite on September 12, 2020, 18:14
Quote from: Carolyn on September 12, 2020, 18:09Youtube vids of rattles and noises are invariably useless! At least you tried.

Time to get your car in front of an educated ear!

Question -does it make the noise when in neutral sitting still? If not -it's probably not coming from the engine itself.

there are ways of pinning these things down..

Only at around 2500 revs, I'm not sure if it's just at that point or if that's when it's most pronounced. Once you accelerate past 2500 revs or let it drop below the noise tails off. It's very loud at this point though and can be heard of the engine/exhaust. It sounds like a reverberation in my opinion.

If it's in neutral sitting still the noise can't be heard.

A bit of sheet metal flapping about could well do it then!

Joesson · September 12, 2020, 18:18

On another thread @The Arch Bishop said:
"Nasty rattle under throttle load (I think the exhaust is leaking somewhere rather than anything catastrophic)"

I said:
Not spoken about on here so much these days but the general rattle on OE exhausts is the heat shield on the main cat.

@Erudite
Maybe like busses, wait for one for ages then two come along!

Ardent · September 12, 2020, 19:12

My 2p stab in the dark.

The spacer? inside the heat shield around the cat

Jamtastic · September 12, 2020, 23:18

Hi Erudite

I had a very similar issue between 2500 to 3000rpm.
2 minutes on an inspection pit and we found it. A piece of heat shield rattling away downstream of the manifold.

Hope it points you in the right direction.

Erudite · September 27, 2020, 17:58

Bit of an update on the car. I've finally found out why it's 'running rich', it's got a decat downpipe 😖

It was only when I started to look for the heat shields around the cat that I realised it didn't have one (this was also after googling 'catalytic converter' to see what one looked like).

I'm going to take it in to get a price for swapping out the downpipe and getting the original put back in.

Not really got any further with identifying the rattling noise. Its getting worse and after much googling I think theres a chance that a baffle has come loose (it's a Malian - possibly a rebranded top speed auto? ). If this is the case I'm thinking the most cost effective course of action may be to get the OEM exhaust put back on. I'll try to get a second opinion when I take it in for the price on the fitting of the cat.

1979scotte · September 27, 2020, 18:09

Friendly mot tester to get that through

Ardent · September 28, 2020, 00:08

Quote from: Erudite on September 27, 2020, 17:58Bit of an update on the car. I've finally found out why it's 'running rich', it's got a decat downpipe 😖

It was only when I started to look for the heat shields around the cat that I realised it didn't have one (this was also after googling 'catalytic converter' to see what one looked like).

I'm going to take it in to get a price for swapping out the downpipe and getting the original put back in.

Not really got any further with identifying the rattling noise. Its getting worse and after much googling I think theres a chance that a baffle has come loose (it's a Malian - possibly a rebranded top speed auto? ). If this is the case I'm thinking the most cost effective course of action may be to get the OEM exhaust put back on. I'll try to get a second opinion when I take it in for the price on the fitting of the cat.

Slow down.
One option my be this.
https://www.cats2u.co.uk/3267-18
Much more £ friendly than OEM.
Plus you could possibly sell the down pipe to offset the cost to you.