Misfire plus odd noise
Discussion
My 2005 automatic DB9 has today developed two problems which I hope someone can shed some light on.
First is a misfire at idle. About every five seconds there is a very slight shudder when sitting in the car. From the outside I can tell the nearside exhaust is the side where the problem is as I can hear and feel a slight "pop". I don't notice any problems driving the car, it only seems to happen at idle. Happens in Park;Neutral;and Drive.
Second problem (only discovered investigating the first), is that when car is at idle and with the door open or standing outside, if i blip the throttle to revs 1800/2000 or more, when I release the throttle, as engine returns to idle there is a "ratchet" sound lasting a couple of seconds coming from somewhere near the rear tyre area of the car. This is on the offside (drivers side) of the car, so opposite from the misfire.
I am obviously going to take it to the dealers to get it looked at but anyone got any clues, especially the ratchety sound?
Peter
First is a misfire at idle. About every five seconds there is a very slight shudder when sitting in the car. From the outside I can tell the nearside exhaust is the side where the problem is as I can hear and feel a slight "pop". I don't notice any problems driving the car, it only seems to happen at idle. Happens in Park;Neutral;and Drive.
Second problem (only discovered investigating the first), is that when car is at idle and with the door open or standing outside, if i blip the throttle to revs 1800/2000 or more, when I release the throttle, as engine returns to idle there is a "ratchet" sound lasting a couple of seconds coming from somewhere near the rear tyre area of the car. This is on the offside (drivers side) of the car, so opposite from the misfire.
I am obviously going to take it to the dealers to get it looked at but anyone got any clues, especially the ratchety sound?
Peter
Not really qualified to answer that but my understanding two gaskets need replacing if your replacing all the coils.....if you haven't had the plugs done then its probably a good idea to have them replaced at the same time .......a diagnostic check by the dealer should tell you if it's a coil..........you could buy the plugs and the coils at less than half the cost from Europarts or similar and have an independent fit them for you......you need to check first which type of coil it is as some have 2pins, some 3
I'm sure somebody will be along shortly to give better advice
I'm sure somebody will be along shortly to give better advice
Edited by michael gould on Sunday 17th February 19:43
Before you take it to a dealers, you might want to find out what the problem is, otherwise the dealers will ask for a blank cheque....
Do you have a OBDII code reader? This will give you a clear indication of what is wrong.
I can guess ......
Your car is 7/8 years old and never had the spark plugs changed (33k and plugs are due at 70k), and a coil (or 2) is probably gone. That won't cost a million pounds and any dealer can help you with it, some are afraid of the car because of the name. Its a relatively straight forward job, take off the 2 large silver air intake manifolds, find out if the Coils are 2 or 3 pin type (AM won't be able to tell you, even if you give them the VIN number) change coils, all of them and spark plugs all of them.
They will want to charge you £180.00 plus vat for a new gasket for the intake manifold, if your engine has never been opened in 8 years, then personally I would change it, if you have had the top off in the last year or so, I would not change it and save over £200.00.
Spark plugs and Coils are an easy job, its just the name, "Aston Martin", that frightens people, Halfords garages could do the job.
Phone around for some prices .......
I would need more info on the rear noise in order to hazard a guess .......
Do you have a OBDII code reader? This will give you a clear indication of what is wrong.
I can guess ......
Your car is 7/8 years old and never had the spark plugs changed (33k and plugs are due at 70k), and a coil (or 2) is probably gone. That won't cost a million pounds and any dealer can help you with it, some are afraid of the car because of the name. Its a relatively straight forward job, take off the 2 large silver air intake manifolds, find out if the Coils are 2 or 3 pin type (AM won't be able to tell you, even if you give them the VIN number) change coils, all of them and spark plugs all of them.
They will want to charge you £180.00 plus vat for a new gasket for the intake manifold, if your engine has never been opened in 8 years, then personally I would change it, if you have had the top off in the last year or so, I would not change it and save over £200.00.
Spark plugs and Coils are an easy job, its just the name, "Aston Martin", that frightens people, Halfords garages could do the job.
Phone around for some prices .......
I would need more info on the rear noise in order to hazard a guess .......
Get it to BR and they will sort it properly. I would not let Halfords fill my washer fluid....Cockernee - just for clarification, I too would not let halfords inflate my tyres, I think my 12 year old knows more than them .... its just an example of the type of job it is. I had to take the car to them (for warranty purposes) to have AirCon checked.......
...... they did not know how to open the bonnet ...... I kid you not, I had to come out and open it for them.
Turning to the misfire, the engine is pretty basic, its just the plugs, coils or injectors, there is not really anything else that can affect what you describe. I can see your issue, if you had a 2012 DBS, then take it to a dealer, with a 2005 DB9 (just like mine), costs are important.
Terrible question to ask, I know ..... but were the plugs actually changed?
If the plugs were changed, then it is highly lightly that the coils are the problem, and it's probably only 1 that is giving you (what I can guess is called a, "random misfire", OBDII will tell you which bank it is as well. You can test the coils and find the bad one. But, if they are all the same age, then the costs of changing them is cheaper than changing one, then the labour charge of changing another etc etc etc.
It could be a faulty Injector, again not a problem. They can be tested and find the bad one, personally I would not do this, if I located the problem as an injector, I'd change all 12, labour wise, they are right on the top of the engine and access is quite easy and does not involve the taking off of the manifolds.
Personally and I mean what I would do and this is NOT advice, then for the cost of the plugs, I would take off the manifolds (NOT replace the gaskets - if you had the plugs changed recently), then replace the plugs and the coils. You cannot tell what types of coils they are until you have them in your hand.
I do not think that you can get the coils from anyone other than AM, plugs you can get from Halfords, personally I got AM ones (I even bought a spare set that is sat in my garage at this very moment)
With the plugs and coils changed, I, "feel', that the problem would be sorted, the Injectors are normally very reliable, but they can be changed after the others as you don't have to take off the manifolds.
Please remember that this is what, "I", would do, and not advice .......
...... they did not know how to open the bonnet ...... I kid you not
, I had to come out and open it for them.Turning to the misfire, the engine is pretty basic, its just the plugs, coils or injectors, there is not really anything else that can affect what you describe. I can see your issue, if you had a 2012 DBS, then take it to a dealer, with a 2005 DB9 (just like mine), costs are important.
Terrible question to ask, I know ..... but were the plugs actually changed?
If the plugs were changed, then it is highly lightly that the coils are the problem, and it's probably only 1 that is giving you (what I can guess is called a, "random misfire", OBDII will tell you which bank it is as well. You can test the coils and find the bad one. But, if they are all the same age, then the costs of changing them is cheaper than changing one, then the labour charge of changing another etc etc etc.
It could be a faulty Injector, again not a problem. They can be tested and find the bad one, personally I would not do this, if I located the problem as an injector, I'd change all 12, labour wise, they are right on the top of the engine and access is quite easy and does not involve the taking off of the manifolds.
Personally and I mean what I would do and this is NOT advice, then for the cost of the plugs, I would take off the manifolds (NOT replace the gaskets - if you had the plugs changed recently), then replace the plugs and the coils. You cannot tell what types of coils they are until you have them in your hand.
I do not think that you can get the coils from anyone other than AM, plugs you can get from Halfords, personally I got AM ones (I even bought a spare set that is sat in my garage at this very moment)
With the plugs and coils changed, I, "feel', that the problem would be sorted, the Injectors are normally very reliable, but they can be changed after the others as you don't have to take off the manifolds.
Please remember that this is what, "I", would do, and not advice .......
The ratchety noise is this :
Car static in neutral/park at idle.....no noise
blip throttle to 1800/2000 rpm or more and release throttle
as rpm returns to idle a "ratchety" noise is heard for about 2 seconds coming from the area around the rear offside tyre. Sounds just like a cog wheel spinning against a tooth....imaging the sound an old bicycle wheel makes if you hold up the rear wheel and turn the pedal by hand, then stop turning the pedal and the wheel continues to turn. I hope i have explained it.
Peter
Car static in neutral/park at idle.....no noise
blip throttle to 1800/2000 rpm or more and release throttle
as rpm returns to idle a "ratchety" noise is heard for about 2 seconds coming from the area around the rear offside tyre. Sounds just like a cog wheel spinning against a tooth....imaging the sound an old bicycle wheel makes if you hold up the rear wheel and turn the pedal by hand, then stop turning the pedal and the wheel continues to turn. I hope i have explained it.
Peter
Likely to be coil pack, and yes all 12 should be done while the manifolds are off (5hrs labour - or at least it was on a DB7). 33k miles is on the low side but if the car has done a lot of short journeys, it seems ro be heat cycles that cause them to fai rather than mileagel. I'd have plugs checked and be prepared to have them changed.
One thing to consider, the misfire will be causing unburnt fuel to get into your catalysts, this will cause the brick to collapse.
Get it sorted immediately at an Aston specialist before your cat is fried, they're not cheap! Don't take it to Kwik Fit FFS
The noise will be better diagnosed by an expert listening to it than some unqualified people on the Internet
One thing to consider, the misfire will be causing unburnt fuel to get into your catalysts, this will cause the brick to collapse.
Get it sorted immediately at an Aston specialist before your cat is fried, they're not cheap! Don't take it to Kwik Fit FFS
The noise will be better diagnosed by an expert listening to it than some unqualified people on the Internet
Rear noise - this is more difficult, and if the car is not moving and the sound happens, then I'm guessing a gearbox or diff issue. If you don't rev past 3.5k / 4k then the exhaust bypass won't cut in. BUt this could be checked quite easily. Take out fuse 22 from the rear fuse box, this will disconnect the vacuum pumps by the rear silencer.
Has the diff oil been changed? Back in 2004/5 when the cars were being developed, the oil was sealed for life. This is rubbish and the oil gets, "burnt", it shuld be changed every 2 years and this is important. Its mineral oil and not synthetic, my car was juddering when making slow turns, researched it and found that the oil was burnt and the clutch plates in the diff were not being lubricated.
Changed the oil and diff was revolutionised, no shuddering, no noise. Although I think the noise was tyres more than anything else.
The diff oil came out black and burnt, the new mineral oil was clear (obvioulsy).
I also changed the auto box oil, because I did not know if the oil had ever been changed or if the oil was burnt. This is more difficult, some gearbox specialist can drain and change the oil, if you want it done yourself, I think the box takes about 10 litres of oil, you can drain down about 4 litres, fill back up, drive, drain down 4 litres, drive, fill back up, drain 4 litres, fill and drive. In effect, you dilute the oil.
When I had this done (this was one of the jobs I did not do myself - it was prior to me doing most things myself), this was done by a Franchise Jag dealer. BUT, the gear oil came out almost as nice as the oil went in, there was a difference, but not much. The diff oil was significant, the gear oil was less than marginal.
I have droned on about oils because that is one of the cheapest, "first looks", the Autobox and Diff, are both normally highly reliable, so if it is Box or Diff, you would be most unfortunate.
If you bought the car from a dealer, is not, "mechanical failure", covered by the warranty .....
Take out fuse 22, change the oils, then see if the noise is still there?
Are you close to the South West of England ?
Has the diff oil been changed? Back in 2004/5 when the cars were being developed, the oil was sealed for life. This is rubbish and the oil gets, "burnt", it shuld be changed every 2 years and this is important. Its mineral oil and not synthetic, my car was juddering when making slow turns, researched it and found that the oil was burnt and the clutch plates in the diff were not being lubricated.
Changed the oil and diff was revolutionised, no shuddering, no noise. Although I think the noise was tyres more than anything else.
The diff oil came out black and burnt, the new mineral oil was clear (obvioulsy).
I also changed the auto box oil, because I did not know if the oil had ever been changed or if the oil was burnt. This is more difficult, some gearbox specialist can drain and change the oil, if you want it done yourself, I think the box takes about 10 litres of oil, you can drain down about 4 litres, fill back up, drive, drain down 4 litres, drive, fill back up, drain 4 litres, fill and drive. In effect, you dilute the oil.
When I had this done (this was one of the jobs I did not do myself - it was prior to me doing most things myself), this was done by a Franchise Jag dealer. BUT, the gear oil came out almost as nice as the oil went in, there was a difference, but not much. The diff oil was significant, the gear oil was less than marginal.
I have droned on about oils because that is one of the cheapest, "first looks", the Autobox and Diff, are both normally highly reliable, so if it is Box or Diff, you would be most unfortunate.
If you bought the car from a dealer, is not, "mechanical failure", covered by the warranty .....
Take out fuse 22, change the oils, then see if the noise is still there?
Are you close to the South West of England ?
Take a look at my video showing the exhaust valve in operation. You can hear the pump noise as the valve operates. Is the noise like this?
http://youtu.be/4GwdMEZDk5g
As for the misfire and shudder I have had the same issue. I took mine to BR and they had a good look at it but could not determine for certain that it was a coil even with data logging and analysing the results. I have found for mine that a good run down drive cleared it.
I find a nice quiet stretch of road say early Sunday morning and get the car thoroughly warm and get up to 70mph or so then come off the gas and let the car run down to 30 mph or so then repeat a couple of times. My plugs were replaced at the 7 year service so that might point to the coil packs but I have no issue during driving whatsoever so how does a coil pack fail at idle but work at higher revs?
BamfordMike mentions it here after I mention the above and also goes into much more detail.
http://www.pistonheads.co.uk/gassing/topic.asp?h=1...
Here is another with a low mileage example
http://www.amoc.org/forum/index.php?action=printpa...
I don't know where you live but BR might be the right choice here just changing out components with 12 plugs and 12 coils plus strip down and rebuild of manifolds is an expensive job to then only find on the way home that the problem remains. For the record if changing the coil packs would cure it I would have it done in a heartbeat but the engine data did not point to that as the cause just that it was on Bank B.
http://youtu.be/4GwdMEZDk5g
As for the misfire and shudder I have had the same issue. I took mine to BR and they had a good look at it but could not determine for certain that it was a coil even with data logging and analysing the results. I have found for mine that a good run down drive cleared it.
I find a nice quiet stretch of road say early Sunday morning and get the car thoroughly warm and get up to 70mph or so then come off the gas and let the car run down to 30 mph or so then repeat a couple of times. My plugs were replaced at the 7 year service so that might point to the coil packs but I have no issue during driving whatsoever so how does a coil pack fail at idle but work at higher revs?
BamfordMike mentions it here after I mention the above and also goes into much more detail.
http://www.pistonheads.co.uk/gassing/topic.asp?h=1...
Here is another with a low mileage example
http://www.amoc.org/forum/index.php?action=printpa...
I don't know where you live but BR might be the right choice here just changing out components with 12 plugs and 12 coils plus strip down and rebuild of manifolds is an expensive job to then only find on the way home that the problem remains. For the record if changing the coil packs would cure it I would have it done in a heartbeat but the engine data did not point to that as the cause just that it was on Bank B.
Edited by SLacKer on Monday 18th February 08:07
pschlute said:
I have never heard it before. Does this suggest a problem with the "pump".
The pump will normally make some noise. Without hearing it I couldn't say if yours was abnormal or not. It's rubber mounted to isolate it but will sound louder if soemthing is touching where it shouldn't.The valves are open at idle and close as the engine speed increases. The pump then runs momentarily if necessary to maintain vacumn in the resevoir. If you want to confirm it is the pump remove the fuse 22 as Maverick says. The same fuse powers both the pump and the solenoid that controls the valves.
pschlute said:
SLacker
Your video displays the sound i am hearing exactly. The "ratchet" sound that starts at 0.09 sec on the video. Only with mine it is apparent when revs are returning to idle.
Thanks for the other links i will have a look.
Peter
That is the pump then. It is mounted behind the rear bumper side behind the rear wheel on the drivers side. It has a reservoir tank where it stores some vacuum so you may hear different things at different times. I had just made some changes to make mine work properly. Your video displays the sound i am hearing exactly. The "ratchet" sound that starts at 0.09 sec on the video. Only with mine it is apparent when revs are returning to idle.
Thanks for the other links i will have a look.
Peter
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