DB9 (30 June 2008) Hesitant Acceleration & Lumpy idle
Discussion
Hi guys,
I have been reading the forum passionately for years but the latest series of events, led me to also become an active member from now onwards.
I would like to start with apologies for taking up your time but I really had no other good source of information. I am in Greece with my UK car and the dealer closed down and have been trying to find a local repairman ever since.
My car is a 30 June 2008 DB9 Facelift (470bhp) with 37500 miles on the meter.
I will give you the series of events that lead to this first:
- My car battery is around 7.5 years old and the previous owner must have replaced it with a simple Varta EFB and not AGM (judging from the price he paid at around 122 pounds beginning of 2017).
- The battery died and I jump started the car
- The car went into "Accident mode" with cabin lights on all the time, even with doors closed, but with everything else working well.
- After driving 20 miles or so, the car went back to "normal", cabin lights went off etc
Now, the last point says "normal" for a reason. I had noticed a little hesitant acceleration when driving those 20 miles, especially between 1500-2000 RPM and gears 4-6 and I was not sure but I thought I noticed a lump at idle too.
Fast forward 4 weeks after summer vacation, battery dead again. I fire up the car with a booster and take it to a shop for a charge. Left it a good 6 hours on the charger. Now, after the charge:
- The car has a check engine light on and clearly audible misfire
- The hesitation when accelerating comes at gears 3-6 1200-2200 RPM
Could this all be the symptoms of a battery just failing to run the car properly? I am very alarmed as the mileage and everything could indicate a coil pack/spark plug job and I am desperate as I do not know what to do in Greece other than take it to Italy to the dealer.
Thank you loads for taking the time to read and apologies for taking up your precious time.
Best regards,
John
I have been reading the forum passionately for years but the latest series of events, led me to also become an active member from now onwards.
I would like to start with apologies for taking up your time but I really had no other good source of information. I am in Greece with my UK car and the dealer closed down and have been trying to find a local repairman ever since.
My car is a 30 June 2008 DB9 Facelift (470bhp) with 37500 miles on the meter.
I will give you the series of events that lead to this first:
- My car battery is around 7.5 years old and the previous owner must have replaced it with a simple Varta EFB and not AGM (judging from the price he paid at around 122 pounds beginning of 2017).
- The battery died and I jump started the car
- The car went into "Accident mode" with cabin lights on all the time, even with doors closed, but with everything else working well.
- After driving 20 miles or so, the car went back to "normal", cabin lights went off etc
Now, the last point says "normal" for a reason. I had noticed a little hesitant acceleration when driving those 20 miles, especially between 1500-2000 RPM and gears 4-6 and I was not sure but I thought I noticed a lump at idle too.
Fast forward 4 weeks after summer vacation, battery dead again. I fire up the car with a booster and take it to a shop for a charge. Left it a good 6 hours on the charger. Now, after the charge:
- The car has a check engine light on and clearly audible misfire
- The hesitation when accelerating comes at gears 3-6 1200-2200 RPM
Could this all be the symptoms of a battery just failing to run the car properly? I am very alarmed as the mileage and everything could indicate a coil pack/spark plug job and I am desperate as I do not know what to do in Greece other than take it to Italy to the dealer.
Thank you loads for taking the time to read and apologies for taking up your precious time.
Best regards,
John
Edited by viglaman on Sunday 10th September 18:37
Edited by viglaman on Monday 11th September 13:18
Caslad said:
Hi John
You definitely need a new battery whatever else might also be at fault.
Do you think that all the source of my problems could be the dying Varta? If you do not drive the car very often, is AGM battery really a better option? Anything you might know on Lithium?You definitely need a new battery whatever else might also be at fault.
Cheers!
I don’t know if the battery is the sole cause of the problems, it does sound like there may be an issue with plugs/coils but the battery is a good place to start. The fact that it’s 7+ years old & has already had problems means it needs replacing imo. I have no experience with lithium batteries.
Caslad said:
I don’t know if the battery is the sole cause of the problems, it does sound like there may be an issue with plugs/coils but the battery is a good place to start. The fact that it’s 7+ years old & has already had problems means it needs replacing imo. I have no experience with lithium batteries.
I will definitely replace it as a starting point. If anybody else has any experience on the beforementioned, much obliged!Hello there, thanks for the intro before the question. You will surely get the help you need from the forum.
First off - replace the battery. Notwithstanding the fact that these cars eat batteries, often due to a faulty tracker module, Sometimes even a new battery can die instantly, even branded ones. They are all likely made in the same old factory somewhere. AGM isn’t necessary. Lithium is better but costly, not really necessary and you will need an installation kit.
Given your location, you need to invest in a decent body and engine OBD reader. There are folks on here who can tell you which is currently best, it may still be the Foxwell. Reading and reporting the fault codes on here will yield helpful suggestions.
First off - replace the battery. Notwithstanding the fact that these cars eat batteries, often due to a faulty tracker module, Sometimes even a new battery can die instantly, even branded ones. They are all likely made in the same old factory somewhere. AGM isn’t necessary. Lithium is better but costly, not really necessary and you will need an installation kit.
Given your location, you need to invest in a decent body and engine OBD reader. There are folks on here who can tell you which is currently best, it may still be the Foxwell. Reading and reporting the fault codes on here will yield helpful suggestions.
Calinours said:
Hello there, thanks for the intro before the question. You will surely get the help you need from the forum.
First off - replace the battery. Notwithstanding the fact that these cars eat batteries, often due to a faulty tracker module, Sometimes even a new battery can die instantly, even branded ones. They are all likely made in the same old factory somewhere. AGM isn’t necessary. Lithium is better but costly, not really necessary and you will need an installation kit.
Given your location, you need to invest in a decent body and engine OBD reader. There are folks on here who can tell you which is currently best, it may still be the Foxwell. Reading and reporting the fault codes on here will yield helpful suggestions.
Thank you very much for the response! I will just take the battery out and replace it asap then to see if it sorts things out at all. I have had crazy stuff happening on other cars I own due to a failing battery so might as well be the case here. AGM charges much quicker than a typical Lead Acid but does not take deep discharge well (should be kept above 50%). Wouldn't an occasional driver benefit from an AGM?First off - replace the battery. Notwithstanding the fact that these cars eat batteries, often due to a faulty tracker module, Sometimes even a new battery can die instantly, even branded ones. They are all likely made in the same old factory somewhere. AGM isn’t necessary. Lithium is better but costly, not really necessary and you will need an installation kit.
Given your location, you need to invest in a decent body and engine OBD reader. There are folks on here who can tell you which is currently best, it may still be the Foxwell. Reading and reporting the fault codes on here will yield helpful suggestions.
Foxwell NT510 you mean right? If anyone can advise on others, much obliged.
I am going mad and almost decided to take the car back to London today. Maybe if no solution is found, I will take it to Izmir in Turkey for a service.
I'm no expert on DB9s but have learned more than I expected to in the almost-two years I've had one.
I suspect that when you left the car for 4 weeks the battery went down to <10V, misfire correction factors were lost and other settings too. It seems too knackered to take a proper charge. So, my suggestion would be (1) new battery (proper one not Mickey Mouse) and (2) do the engine run-downs to reset correction factors. The boys who designed the ECUs reckoned that doing 5x 70-20mph rundowns without touching any controls was such fun to try on public roads they designed it that way specially...
So, easy obvious things first - don't expect any old dealer/garage to diagnose it, you could just up spending £££ for them to look in the wrong place.
Also suggest that you use a battery conditioner if leaving the car for more than a week.
PS And yes a Foxwell with their AM software can measure misfires by cylinder if the above doesn't fix it.
I suspect that when you left the car for 4 weeks the battery went down to <10V, misfire correction factors were lost and other settings too. It seems too knackered to take a proper charge. So, my suggestion would be (1) new battery (proper one not Mickey Mouse) and (2) do the engine run-downs to reset correction factors. The boys who designed the ECUs reckoned that doing 5x 70-20mph rundowns without touching any controls was such fun to try on public roads they designed it that way specially...
So, easy obvious things first - don't expect any old dealer/garage to diagnose it, you could just up spending £££ for them to look in the wrong place.
Also suggest that you use a battery conditioner if leaving the car for more than a week.
PS And yes a Foxwell with their AM software can measure misfires by cylinder if the above doesn't fix it.
Edited by Simpo Two on Sunday 10th September 20:52
Sealed Glass Matt (AGM) batteries were designed for deep cycle use and reduced off gassing for confined spaces. Camper vans, marine, etc.
Their principle benefit from automotive perspective is that they handle repeated heavy load a little better so are generally recommended for stop-start application.
The lower internal resistance/faster charging argument is often over stated. If your car starts rapidly then the CCA capacity taken from the battery will be replaced within a few minutes of driving. The claimed ability to deep cycle down to a claimed 80% discharge without sulphation damage, as opposed to the 50% of flooded is also often overstated. Lithiums can definitely do this without damage, not any type of lead acid. Most folk I know try to never cycle even AGM lead batteries below 50% discharge.
Maybe if you have an electrical issue that is killing your battery, an AGM might last longer, personally I would find whatever the current leak is. Once you have a new battery the first thing to check is the factory tracker. Many of us just disable the old tracker to resolve the flat battery issue, but these cars do seem to still have a pretty heavy alarm current drain, 2-3 weeks seems about the limit. All cars of the same era with sophisticated alarms, remote locking etc were similar, it’s why conditioners became popular. Porsche always used to, from 996 onward, automatically disable the alarm after 2 or 3 weeks to ensure enough battery remained to be able to unlock and start the engine after a month.
There is a downside to AGM, they do not handle overcharging very well, and every time you are driving your car, this is exactly what your 14.4V alternator is trying to do to your battery.
On balance, if your car ms electrics are good, you use it regularly and/or have a conditioner, there is little real benefit from AGM. If you leave it long periods without conditioner there may be some benefit, but balance it against the overcharge risk.
Their principle benefit from automotive perspective is that they handle repeated heavy load a little better so are generally recommended for stop-start application.
The lower internal resistance/faster charging argument is often over stated. If your car starts rapidly then the CCA capacity taken from the battery will be replaced within a few minutes of driving. The claimed ability to deep cycle down to a claimed 80% discharge without sulphation damage, as opposed to the 50% of flooded is also often overstated. Lithiums can definitely do this without damage, not any type of lead acid. Most folk I know try to never cycle even AGM lead batteries below 50% discharge.
Maybe if you have an electrical issue that is killing your battery, an AGM might last longer, personally I would find whatever the current leak is. Once you have a new battery the first thing to check is the factory tracker. Many of us just disable the old tracker to resolve the flat battery issue, but these cars do seem to still have a pretty heavy alarm current drain, 2-3 weeks seems about the limit. All cars of the same era with sophisticated alarms, remote locking etc were similar, it’s why conditioners became popular. Porsche always used to, from 996 onward, automatically disable the alarm after 2 or 3 weeks to ensure enough battery remained to be able to unlock and start the engine after a month.
There is a downside to AGM, they do not handle overcharging very well, and every time you are driving your car, this is exactly what your 14.4V alternator is trying to do to your battery.
On balance, if your car ms electrics are good, you use it regularly and/or have a conditioner, there is little real benefit from AGM. If you leave it long periods without conditioner there may be some benefit, but balance it against the overcharge risk.
Calinours said:
There is a downside to AGM, they do not handle overcharging very well, and every time you are driving your car, this is exactly what your 14.4V alternator is trying to do to your battery.
Why do they (the automotive industry) use alternators that overcharge the battery? Can't they be 'intelligent'?Simpo Two said:
I'm no expert on DB9s but have learned more than I expected to in the almost-two years I've had one.
I suspect that when you left the car for 4 weeks the battery went down to <10V, misfire correction factors were lost and other settings too. It seems too knackered to take a proper charge. So, my suggestion would be (1) new battery (proper one not Mickey Mouse) and (2) do the engine run-downs to reset correction factors. The boys who designed the ECUs reckoned that doing 5x 70-20mph rundowns without touching any controls was such fun to try on public roads they designed it that way specially...
So, easy obvious things first - don't expect any old dealer/garage to diagnose it, you could just up spending £££ for them to look in the wrong place.
Also suggest that you use a battery conditioner if leaving the car for more than a week.
PS And yes a Foxwell with their AM software can measure misfires by cylinder if the above doesn't fix it.
I am thinking of going for a Varta G14 and doing the 70-20mph rundowns and take it from there. So below 10 volts is the real problem I understand.I suspect that when you left the car for 4 weeks the battery went down to <10V, misfire correction factors were lost and other settings too. It seems too knackered to take a proper charge. So, my suggestion would be (1) new battery (proper one not Mickey Mouse) and (2) do the engine run-downs to reset correction factors. The boys who designed the ECUs reckoned that doing 5x 70-20mph rundowns without touching any controls was such fun to try on public roads they designed it that way specially...
So, easy obvious things first - don't expect any old dealer/garage to diagnose it, you could just up spending £££ for them to look in the wrong place.
Also suggest that you use a battery conditioner if leaving the car for more than a week.
PS And yes a Foxwell with their AM software can measure misfires by cylinder if the above doesn't fix it.
Edited by Simpo Two on Sunday 10th September 20:52
Calinours said:
Sealed Glass Matt (AGM) batteries were designed for deep cycle use and reduced off gassing for confined spaces. Camper vans, marine, etc.
Their principle benefit from automotive perspective is that they handle repeated heavy load a little better so are generally recommended for stop-start application.
The lower internal resistance/faster charging argument is often over stated. If your car starts rapidly then the CCA capacity taken from the battery will be replaced within a few minutes of driving. The claimed ability to deep cycle down to a claimed 80% discharge without sulphation damage, as opposed to the 50% of flooded is also often overstated. Lithiums can definitely do this without damage, not any type of lead acid. Most folk I know try to never cycle even AGM lead batteries below 50% discharge.
Maybe if you have an electrical issue that is killing your battery, an AGM might last longer, personally I would find whatever the current leak is. Once you have a new battery the first thing to check is the factory tracker. Many of us just disable the old tracker to resolve the flat battery issue, but these cars do seem to still have a pretty heavy alarm current drain, 2-3 weeks seems about the limit. All cars of the same era with sophisticated alarms, remote locking etc were similar, it’s why conditioners became popular. Porsche always used to, from 996 onward, automatically disable the alarm after 2 or 3 weeks to ensure enough battery remained to be able to unlock and start the engine after a month.
There is a downside to AGM, they do not handle overcharging very well, and every time you are driving your car, this is exactly what your 14.4V alternator is trying to do to your battery.
On balance, if your car ms electrics are good, you use it regularly and/or have a conditioner, there is little real benefit from AGM. If you leave it long periods without conditioner there may be some benefit, but balance it against the overcharge risk.
Sounds like the extra 30-50% might be a good premium to pay in my case... AGMs handle extreme bursts of voltage quite well actually so a lot of power coming in from the alternator is good for them. As for the overcharging bit...You are right I believe but could the alternator overcharge a battery or even get it to 100%?Their principle benefit from automotive perspective is that they handle repeated heavy load a little better so are generally recommended for stop-start application.
The lower internal resistance/faster charging argument is often over stated. If your car starts rapidly then the CCA capacity taken from the battery will be replaced within a few minutes of driving. The claimed ability to deep cycle down to a claimed 80% discharge without sulphation damage, as opposed to the 50% of flooded is also often overstated. Lithiums can definitely do this without damage, not any type of lead acid. Most folk I know try to never cycle even AGM lead batteries below 50% discharge.
Maybe if you have an electrical issue that is killing your battery, an AGM might last longer, personally I would find whatever the current leak is. Once you have a new battery the first thing to check is the factory tracker. Many of us just disable the old tracker to resolve the flat battery issue, but these cars do seem to still have a pretty heavy alarm current drain, 2-3 weeks seems about the limit. All cars of the same era with sophisticated alarms, remote locking etc were similar, it’s why conditioners became popular. Porsche always used to, from 996 onward, automatically disable the alarm after 2 or 3 weeks to ensure enough battery remained to be able to unlock and start the engine after a month.
There is a downside to AGM, they do not handle overcharging very well, and every time you are driving your car, this is exactly what your 14.4V alternator is trying to do to your battery.
On balance, if your car ms electrics are good, you use it regularly and/or have a conditioner, there is little real benefit from AGM. If you leave it long periods without conditioner there may be some benefit, but balance it against the overcharge risk.
I will look to change the battery this Friday-Saturday and take it from there. I have found a garage in Athens that claims they can do DB9 servicing and actually saw DB9s on their Facebook profile. This could help avoid going back to London or travelling to Izmir.
8Tech said:
Replace the battery with a good quality, branded lead acid sealed battery and that will be the end of your problems.
Pointless spending anymore time on it until that is resolved.
Right on. Ditching the old Varta this weekend and we take it from there. I have been also told to get a ThinkDiag (but Mini, 1 or 2??) but I am slightly confused as to how the subscription works.Pointless spending anymore time on it until that is resolved.
I recently also experienced battery issues on my 2008 DB9, even with CTEK charger... .
First of all, keep it (if possible) in a closed garage with the window on driver side slightly open so that side window does not get 'stuck' when you open the car with flat battery (window no longer drops a bit if battery is flat).
I jumpstarted the car but next day was flat again, even after having driven it for an hour and back on CTEK charger.
In the end, decided to replace the battery at dealer as it is a bit complicated (stored under rear seat with difficult access). On the way to the dealer, had many different alarm signals on dashboard and also went into 'go home' mode or similar with no possibility to change gears... .
In the end, dealer replaced battery and did a reset of all functions. They told me the previous owner had installed an additional alarm system, which was probably one of the reasons the battery died... .
Now having that alarm system removed at the dealer.
For info, whole battery exchange and diagnostics thing cost me about 500 EUR.
Cheers,
Frank
(Belgium)
First of all, keep it (if possible) in a closed garage with the window on driver side slightly open so that side window does not get 'stuck' when you open the car with flat battery (window no longer drops a bit if battery is flat).
I jumpstarted the car but next day was flat again, even after having driven it for an hour and back on CTEK charger.
In the end, decided to replace the battery at dealer as it is a bit complicated (stored under rear seat with difficult access). On the way to the dealer, had many different alarm signals on dashboard and also went into 'go home' mode or similar with no possibility to change gears... .
In the end, dealer replaced battery and did a reset of all functions. They told me the previous owner had installed an additional alarm system, which was probably one of the reasons the battery died... .
Now having that alarm system removed at the dealer.
For info, whole battery exchange and diagnostics thing cost me about 500 EUR.
Cheers,
Frank
(Belgium)
pbe624 said:
I recently also experienced battery issues on my 2008 DB9, even with CTEK charger... .
First of all, keep it (if possible) in a closed garage with the window on driver side slightly open so that side window does not get 'stuck' when you open the car with flat battery (window no longer drops a bit if battery is flat).
I jumpstarted the car but next day was flat again, even after having driven it for an hour and back on CTEK charger.
In the end, decided to replace the battery at dealer as it is a bit complicated (stored under rear seat with difficult access). On the way to the dealer, had many different alarm signals on dashboard and also went into 'go home' mode or similar with no possibility to change gears... .
In the end, dealer replaced battery and did a reset of all functions. They told me the previous owner had installed an additional alarm system, which was probably one of the reasons the battery died... .
Now having that alarm system removed at the dealer.
For info, whole battery exchange and diagnostics thing cost me about 500 EUR.
Cheers,
Frank
(Belgium)
So there is hope it seems and my friend from Land Rover was right...The battery DOES tend to cause crazy situations. Will know in a few days Frank. Will have to rely on a battery shop to change the battery for me however I am afraid as no dealer here.First of all, keep it (if possible) in a closed garage with the window on driver side slightly open so that side window does not get 'stuck' when you open the car with flat battery (window no longer drops a bit if battery is flat).
I jumpstarted the car but next day was flat again, even after having driven it for an hour and back on CTEK charger.
In the end, decided to replace the battery at dealer as it is a bit complicated (stored under rear seat with difficult access). On the way to the dealer, had many different alarm signals on dashboard and also went into 'go home' mode or similar with no possibility to change gears... .
In the end, dealer replaced battery and did a reset of all functions. They told me the previous owner had installed an additional alarm system, which was probably one of the reasons the battery died... .
Now having that alarm system removed at the dealer.
For info, whole battery exchange and diagnostics thing cost me about 500 EUR.
Cheers,
Frank
(Belgium)
I do keep the car with open bonnet in a garage in order to be able to revive it if needs be as the previous owner did not give me the key that opens the doors manually. Good advice on the door too.
The additional key is a simple metal key, I think you should be able to order it at astonmartinbits... . Don't think it is specific to a particular car. Recommend to get one so you can always open the door.
PS: if battery is dead, you can access the rear seat by moving front seatback forward. However, the electric button at the top won't work, so you need to pull up the handle/cord between bottom of the headrest and top of the driver seat. This will allow to move the driver seatback forward (check your manual if you have one) or check youtube, there is a clip explaining this.
Good luck,
Frank
PS: if battery is dead, you can access the rear seat by moving front seatback forward. However, the electric button at the top won't work, so you need to pull up the handle/cord between bottom of the headrest and top of the driver seat. This will allow to move the driver seatback forward (check your manual if you have one) or check youtube, there is a clip explaining this.
Good luck,
Frank
pbe624 said:
The additional key is a simple metal key, I think you should be able to order it at astonmartinbits... . Don't think it is specific to a particular car. Recommend to get one so you can always open the door.
PS: if battery is dead, you can access the rear seat by moving front seatback forward. However, the electric button at the top won't work, so you need to pull up the handle/cord between bottom of the headrest and top of the driver seat. This will allow to move the driver seatback forward (check your manual if you have one) or check youtube, there is a clip explaining this.
Good luck,
Frank
HWM also have them in stock too.PS: if battery is dead, you can access the rear seat by moving front seatback forward. However, the electric button at the top won't work, so you need to pull up the handle/cord between bottom of the headrest and top of the driver seat. This will allow to move the driver seatback forward (check your manual if you have one) or check youtube, there is a clip explaining this.
Good luck,
Frank
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