Popping noise / butterfly twitch
Discussion
After washing my V8V 4.3 I often run the engine to help dry off the engine bay area.
A while ago I noticed a soft popping noise. This only happens when the car has been running but not moving for a good while - as per situation above. The engine by this time must be fairly warm.
It's not rhythmic - mechanical. Rather fairly random. It sounds as though it comes from the engine bay area near the inlet manifold - but sounds are tricky to place so this may be unreliable information.
After some time chasing this noise it has been discovered that when the pop occurs the electronic butterfly valve controller twitches, opening the butterfly valve fractionally.
When the electronic butterfly valve is disconnected the popping and the twitching stops.
Has anyone else experienced something similar. Is it a known issue. Is it likely caused by faulty butterfly electronic control unit or by a sensor that's remote from the butterfly but which sends a signal to it?
A while ago I noticed a soft popping noise. This only happens when the car has been running but not moving for a good while - as per situation above. The engine by this time must be fairly warm.
It's not rhythmic - mechanical. Rather fairly random. It sounds as though it comes from the engine bay area near the inlet manifold - but sounds are tricky to place so this may be unreliable information.
After some time chasing this noise it has been discovered that when the pop occurs the electronic butterfly valve controller twitches, opening the butterfly valve fractionally.
When the electronic butterfly valve is disconnected the popping and the twitching stops.
Has anyone else experienced something similar. Is it a known issue. Is it likely caused by faulty butterfly electronic control unit or by a sensor that's remote from the butterfly but which sends a signal to it?
I had exactly the same problem with my 2006 V8 Vantage.
I spent a load of time trying to find out why I got a popping noise from around the induction area when the car was fully up to temperature. It didn't do it during warm up, and the car drove perfectly.
I thought it could be the EGR valve popping off, so i fitted a new one but it made no difference.
The butterfly is electrically operated via the ECU, so if the noise disappears when the plug is disconnected it is definitely the same problem that I had.
It turned out to be the butterfly sticking a bit when fully closed. This causes the throttle actuator to open a bit to keep the idle speed correct and then close again. When the butterfly sticks it pings open and then it oscillates causing the pops at idle.
The problem was solved by cleaning the throttle body and polishing out a very slight burr where the butterfly touched the throttle body when the throttle was in the closed position which caused it to stick very slightly, but only at hot idle.
The reason it doesn't do it until the engine is fully warm is because when the engine is cold and during warm up, the idle is automatically set a bit higher than normal, so the butterfly doesn't close far enough for it to stick.
I hope this is helpful as I was quite worried that there was something seriously amiss as it sounded horrible, a bit like a sticking inlet valve. However, it turned out to be quite a simple fix.
This was a couple of years ago. Not had the problem occur again since.
Regards
Mike
I spent a load of time trying to find out why I got a popping noise from around the induction area when the car was fully up to temperature. It didn't do it during warm up, and the car drove perfectly.
I thought it could be the EGR valve popping off, so i fitted a new one but it made no difference.
The butterfly is electrically operated via the ECU, so if the noise disappears when the plug is disconnected it is definitely the same problem that I had.
It turned out to be the butterfly sticking a bit when fully closed. This causes the throttle actuator to open a bit to keep the idle speed correct and then close again. When the butterfly sticks it pings open and then it oscillates causing the pops at idle.
The problem was solved by cleaning the throttle body and polishing out a very slight burr where the butterfly touched the throttle body when the throttle was in the closed position which caused it to stick very slightly, but only at hot idle.
The reason it doesn't do it until the engine is fully warm is because when the engine is cold and during warm up, the idle is automatically set a bit higher than normal, so the butterfly doesn't close far enough for it to stick.
I hope this is helpful as I was quite worried that there was something seriously amiss as it sounded horrible, a bit like a sticking inlet valve. However, it turned out to be quite a simple fix.
This was a couple of years ago. Not had the problem occur again since.
Regards
Mike
Thanks for posting this very helpful information Mike. It's great to hear from someone else who has not only experienced the same but knows what it is.
This has been going on for some time so I'd hoped that perhaps I'd hear from others whose car did something similar and conclude it was a common problem and perhaps something I could let lie.
Being able to get rid of the symptom would be ideal. As you say the car drives well otherwise, but the noise is worrying.
I'll try a full clean and look for a burr to polish down.
Steve
This has been going on for some time so I'd hoped that perhaps I'd hear from others whose car did something similar and conclude it was a common problem and perhaps something I could let lie.
Being able to get rid of the symptom would be ideal. As you say the car drives well otherwise, but the noise is worrying.
I'll try a full clean and look for a burr to polish down.
Steve
Hi Steve
Thanks for your message.
I'm sure that you have the same problem that I had.
Mine was quite loud when it was doing it, particularly when stopped in traffic or at traffic lights. People would give funny looks if they were standing close by.
As I said, I was really quite concerned as it sounded like the engine was popping back through the induction system which led me to think it could have been a sticking inlet valve. I was getting concerned that I was looking at a really expensive repair bill.
However, I would have expected it to do it all the time if that was a valve, and like yours it only seemed to happen when fully up to temperature and at idle.
If you take your throttle body off of the engine (its only 4 nuts, the plastic inlet pipe and the electrical plug) give it a good clean with carb cleaner, open the butterfly valve by hand and give the area where the butterfly's touch the throttle body casting when it is in the closed position a polish up with a piece of fine emery cloth to make sure that area is smooth, should do the trick.
Mind your fingers when you operate the butterfly by hand as the spring is quite strong.
Aston Martin recommend that you use a new metal gasket between the throttle body and the inlet manifold, but I carefully re-used the original and don't have any air leaks and all is fine now.
Good luck with sorting yours, let us know if the fix is successful for you too.
Cheers
Mike
Thanks for your message.
I'm sure that you have the same problem that I had.
Mine was quite loud when it was doing it, particularly when stopped in traffic or at traffic lights. People would give funny looks if they were standing close by.
As I said, I was really quite concerned as it sounded like the engine was popping back through the induction system which led me to think it could have been a sticking inlet valve. I was getting concerned that I was looking at a really expensive repair bill.
However, I would have expected it to do it all the time if that was a valve, and like yours it only seemed to happen when fully up to temperature and at idle.
If you take your throttle body off of the engine (its only 4 nuts, the plastic inlet pipe and the electrical plug) give it a good clean with carb cleaner, open the butterfly valve by hand and give the area where the butterfly's touch the throttle body casting when it is in the closed position a polish up with a piece of fine emery cloth to make sure that area is smooth, should do the trick.
Mind your fingers when you operate the butterfly by hand as the spring is quite strong.
Aston Martin recommend that you use a new metal gasket between the throttle body and the inlet manifold, but I carefully re-used the original and don't have any air leaks and all is fine now.
Good luck with sorting yours, let us know if the fix is successful for you too.
Cheers
Mike
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