Cold Start Noise

Blueflash

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Electrical motor? Bit like a hair dryer or fan? Secondary air pump. I *think* 'they all do that, sir' Mine certainly does :)

Injectors sound like a light clicking noise as opposed to a valve much heavier tapping of banging. If you imagine 8 small solenoids going off, once per cylinder ignition you'll get the idea :)

C
Phew… my car is 4.7 from 2014, and reckon I’m hearing the injectors for about 60secs on cold starts.
 

Zep

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You can hear them all of the time, but perhaps you are just getting used to it.
 

Blueflash

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You can hear them all of the time, but perhaps you are just getting used to it.
Yeah, had 911s for past 18 years and a TVR before that. Last car I heard injectors on was a Mitsubishi GTO… but that was front engined, so could only hear them with the bonnet open. Had forgotten what they sounded like. But yeah, it’s a perfect clickety 8-beat, at idle, when cold.
 

Zep

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Yeah, had 911s for past 18 years and a TVR before that. Last car I heard injectors on was a Mitsubishi GTO… but that was front engined, so could only hear them with the bonnet open. Had forgotten what they sounded like. But yeah, it’s a perfect clickety 8-beat, at idle, when cold.

My point is that the injectors make that noise all of the time, not just when the engine is cold.
 

Blueflash

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@conaero @Zep

Here's a link to a movie of a cold start I took this morning. Sort of a "brrrrrrrrrrrr" like the world's smallest jackhammer, which I *hope* is just the injectors. You can hear it throughout, but it's more pronounced near the end of the clip. This is noticeable inside the cabin during a cold start, but becomes less pronounced as the engine heats up, and within 5 mins can no longer be distinguished during driving.

Car is a stock 2014 Granturismo Sport Auto 4.7, with 24,000 miles.

 
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Blueflash

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I'd listen to that and think injectors, but the experts will be back shortly

C
Thanks. Inconsistent noises seem to be a feature of Italian engines. It’s the same with my Ducati, and especially my Laverda. Whereas the likes of a Porsche, a BMW, or a Kawasaki tend to produce the same limited repertoire of “click”, “whir”, “broom” and “woosh” noises under a discrete set of conditions (unless something is wrong with them)… Italian motors often seemingly emit a much larger and more nuanced vocabulary… depending on how they are ‘feeling’ at any given moment in time.

This can lead to paranoia.
 
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conaero

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Ok, so I have had a good listen to this. First thing of note, your dipstick is not pushed all the way home.

The sewing machine sound are the injectors and totally normal but if you listen on, you can hear like a washing machine on full spin type of sound which suggest chain or more so chain guide. Its common for the top half of the nylon chain guide to snap off and sit in the bottom of the front cover.

I don't know which part of the country you are in but I would take it to an expert so they can have a proper listen.

Not trying to scare you, its difficult to determine from an audio clip but I would be putting a listening probe on the front timing case around here (directly below the alternator):

images.jpeg
 

Blueflash

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Ok, so I have had a good listen to this. First thing of note, your dipstick is not pushed all the way home.

The sewing machine sound are the injectors and totally normal but if you listen on, you can hear like a washing machine on full spin type of sound which suggest chain or more so chain guide. Its common for the top half of the nylon chain guide to snap off and sit in the bottom of the front cover.

I don't know which part of the country you are in but I would take it to an expert so they can have a proper listen.

Not trying to scare you, its difficult to determine from an audio clip but I would be putting a listening probe on the front timing case around here (directly below the alternator):

View attachment 127000
Thanks.

Can you tell me what time in the video you can hear the washing machine noise? Is that where it sounds like an electric cooling fan kicking in at 1m15s?

I’m 35 miles Northwest of Aberdeen. Nearest specialist is 200 miles away. The car isn’t misfiring and no checklight on, but how risky is it to drive if this is suspected? And how easy would it be to repair?

I’ve ordered a mechanic’s stethoscope in the meantime.
 
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Sam McGoo

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1,793
@conaero @Zep

Here's a link to a movie of a cold start I took this morning. Sort of a "brrrrrrrrrrrr" like the world's smallest jackhammer, which I *hope* is just the injectors. You can hear it throughout, but it's more pronounced near the end of the clip. This is noticeable inside the cabin during a cold start, but becomes less pronounced as the engine heats up, and within 5 mins can no longer be distinguished during driving.

Car is a stock 2014 Granturismo Sport Auto 4.7, with 24,000 miles.


On that video it sounds like there is a deeper knock/rattle sound than the normal injector ticking, which is is more of a tick than a knock. But as said, on a video its hard to know, as the phone mic will pick up stuff our ears my hear differently.

Does it sound the same now you've pushed the dipstick pushed back in?

I'm actually in Aberdeen in the morning and would be happy to have a listen if your near the airport between 1000 -1200. I'm not an expert and won't have any tools or anything with me, but I've had a couple and think I'd be able to tell if it sounded 'normal' or not. But I suppose if it goes away when warm, that's not a lot of use, as it'd be well warm by the time you got here.
 

Blueflash

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On that video it sounds like there is a deeper knock/rattle sound than the normal injector ticking, which is is more of a tick than a knock. But as said, on a video its hard to know, as the phone mic will pick up stuff our ears my hear differently.

Does it sound the same now you've pushed the dipstick pushed back in?

I'm actually in Aberdeen in the morning and would be happy to have a listen if your near the airport between 1000 -1200. I'm not an expert and won't have any tools or anything with me, but I've had a couple and think I'd be able to tell if it sounded 'normal' or not. But I suppose if it goes away when warm, that's not a lot of use, as it'd be well warm by the time you got here.
Thanks for the offer. I’m setting up a friend’s motorcycle suspension tomorrow morning, so wouldn’t be able to make it over to the airport. I haven’t started the motor since shooting the video, am waiting for a stethoscope to arrive.

The car only has 24,000 miles and has had specialist servicing its entire life, with an oil change every year, so would be surprised if there were any issues with the cam chain, but it’s possible that the plastic guides might have deteriorated with age.

The video does sound quite different to reality; phone mics aren’t the best for this.

Think the noise I originally heard might just be the lifters before they warm up, as it stops within 5 mins. Once warmed up the engine sounds very smooth, and the only other sound is the injectors working, and I can’t hear those from inside the cabin, only with the bonnet open.

Won’t start the car again until the stethoscope comes (hopefully tomorrow or Friday).
 

Sam McGoo

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1,793
Thanks for the offer. I’m setting up a friend’s motorcycle suspension tomorrow morning, so wouldn’t be able to make it over to the airport. I haven’t started the motor since shooting the video, am waiting for a stethoscope to arrive.

The car only has 24,000 miles and has had specialist servicing its entire life, with an oil change every year, so would be surprised if there were any issues with the cam chain, but it’s possible that the plastic guides might have deteriorated with age.

The video does sound quite different to reality; phone mics aren’t the best for this.

Think the noise I originally heard might just be the lifters before they warm up, as it stops within 5 mins. Once warmed up the engine sounds very smooth, and the only other sound is the injectors working, and I can’t hear those from inside the cabin, only with the bonnet open.

Won’t start the car again until the stethoscope comes (hopefully tomorrow or Friday).
Yeah, at that year and mileage it would be a suprise for there to be a serious issue. It's probably just new car paranoia.
 

Harvey_Tim

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217
Just out of interest, if the plastic chain guides have worn or snapped what sort of damage can this cause to the engine and how costly is the repair?
 

Blueflash

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Just out of interest, if the plastic chain guides have worn or snapped what sort of damage can this cause to the engine and how costly is the repair?
I’m no expert, but from what I can gather it depends on where the chain guide travels to/lodges, and whether the timing slips before you realise what’s happened… and by how much. If it has slipped at all then the car will likely be misfiring, but there might not be any catastrophic damage if it’s only slipped 1-2 teeth.

Assuming no piston to valve contact, then parts seem to run to a grand for new chains and guides.

Labour seems to be in the region of 2-3 days, as it takes several hours just to get into the timing cover, but once it’s opened up changing the chains and guides doesn’t appear to the all that tricky (provided you stop the cams from turning). Setting the timing can be a bit weird, because being Italian the timing marks haven’t always been aligned, and so need sanity checked.

Best case scenario in the region of 5 grand.

Correct me if I’m wrong.
 

philw696

Member
Messages
25,685
Timing can only be set up properly with dial gauges and a timely process to get it right.
The easy part is removing and refitting the valve covers and the front timing cover.
It's a job that can't be rushed for sure.