Engine cutting out V8V 4.7

[BingoBob]

My car has been doing this very occasionally since I have owned it. Yesterday it did it again in the middle of a dangerous crossroads.

When I accelerate (softly, moderately, hard, seems to make no difference) then sometimes the engine cuts out for half a second causing the car to lurch violently as if I'd just jabbed the brakes. The engine then carries on as normal, leaving me looking like I can't drive my own car - an impression which I am quite capable of giving without any assistance from the engine.

I'm a bit stumped on this one. Anyone got any ideas? End of warranty approaching, but I've got no way to reproduce the problem.

[mikey k]

Infamous throttle body clean?

[Lunablack]

Ak the dealer to interrogate the ECU..... It's amazing what info is stored in there....

Rick from DMS told me that it was obvious that I drive with mechanical sympathy, because he coud check engine temps against engine revs, max revs and speeds, max revs in gears and lots and lots of other stuff...

He could even tell when my thermostat failed, as correct engine temps weren't being reached

Edited by Lunablack on Monday 27th August 09:26

[keith52]

Hi
Had the same problem with my 2010v8v 9k on the clock, recently had it serviced at HWM they updated the software to rectify this problem no problems since

keith

[BingoBob]

Thanks for the info. I like the sound of a firmware update. It definitely feels ECU related. I'll put my code reader on the car to see if anything is stored, but I suspect AMDS will be needed to access the information you are alluding to.

[Grant3]

Hi Bob, this was pretty common on some early 4.7's, below is a link to one of the earlier threads...best of luck

http://www.pistonheads.com/gassing/topic.asp?h=0&a...

[BingoBob]

Thanks, Grant. An interesting read, but no conclusive solutions, unfortunately.

Need to get this sorted under warranty. I don't want to be hit for a 3 grand bill for changing a fuel tank!

[BamfordMike]

BingoBob said:

Thanks, Grant. An interesting read, but no conclusive solutions, unfortunately.

Need to get this sorted under warranty. I don't want to be hit for a 3 grand bill for changing a fuel tank!

The link below on 8th July 2011 is where what sounds like similar, if not the same problem was encountered by JohnG1 (a much liked fellow and much missed forum member)

It sounds like both the root cause of problem and correction of that problem under warranty is well known / nothing new to factory and not just JohnG1 but many BR customers have had this corrective work done under warranty also.

http://www.pistonheads.com/gassing/topic.asp?h=0&a...

hope this helps your discussions and helps enable fix under warranty

[BamfordMike]

Lunablack said:

Rick from DMS told me that it was obvious that I drive with mechanical sympathy, because he coud check engine temps against engine revs, max revs and speeds, max revs in gears and lots and lots of other stuff...

He could even tell when my thermostat failed, as correct engine temps weren't being reached

Edited by Lunablack on Monday 27th August 09:26

I have to make comment on this as some regulars have been in touch to say if I can perform the same....

....I can't.... cos its not possible....!

Im sorry to say that the only data-logging performed by the ECU is when a serious emissions critical fault code is triggered. When one of these codes are triggered a snap-shot of pertinent variables are recorded to help enable resolution of the problem.

Engine temps, maximum revs ever seen, in what gears and any other stuff to 'index' how the car has been used is not available and is simply not true. Some engine temp and rev info is available when a fault code is triggered, but as stated, this will only be a snap-shot and if the fault occurred at idle, the snap-shot will have been taken at idle.

When the seal on the thermostat fails and holds open the stat, that error can be seen on coolant gauge on dashboard because if ever, the engine takes an age to reach normal operating temperature.

[Lunablack]

As I said, I can only go on what Rick told me...... He said that he could see revs against engine temp.... Max revs, max speeds and lots of other stuff....

Maybe he was full of BS after all........ But I believed him, because, I do allow proper warm up etc...



There is also a section in my manual that says..and I quote


"DATA RECORDING"
Computers in your vehicle are capable of recording detailed data, potentially including but not limited to information such as

1. The use of restraint systems including seatbelts by the driver and passenger
2. Information about the performance of various systems and modules in the vehicle
3. Information related to engine, throttle, steering, brake or other system status

Any of this information could potentially include information how the driver operates the vehicle, potentially including but not limited to information regarding vehicle speed, brake, throttle application or steering input.

This information may be stored under regular operation, in a crash or near crash event.

This information may be read and used by:
1. Aston Martin
2. Service and repair facilities
3. Law enforcement or government agencies
4. Others who may assert a right to obtain your consent to know such information..



So is the info available or not??? The manual seems to suggest that it is

Edited by Lunablack on Tuesday 28th August 22:45

[BamfordMike]

Lunablack said:

So is the info available or not??? The manual seems to suggest that it is

Edited by Lunablack on Tuesday 28th August 22:45

As i said, snap shot data is available when something serious happens. In the examples you state from handbook; when crash mode is detected or emissions fault codes are triggered.

The info recorded in these situations is a basic freeze frame of variables, this data can not be used to 'index' how a car has being driven, it just contains engine speed, road speed and other stuff when the event occurred.

If you have never used your airbags or had a check engine light, you would have never recorded such data, as most cars / drivers do not.

So yes and as i first said, some data is taken in extremes but this data can never be used to gauge how well, or bad the owner drives the car.

[BingoBob]

Thanks for that, Mike.

It looks like another vote for the fuel tank.

I am concerned that I won't be able to get my dealer to take this issue seriously. I am thinking of contacting AMHQ directly to see if they know about the problem before I approach the dealer. Is this a good idea?

[Jockman]

BamfordMike said:

So yes and as i first said, some data is taken in extremes but this data can never be used to gauge how well, or bad the owner drives the car.

Indeed.

As JohnG1 pointed out before he resorted to stalking us a few months back, much of this information is not sufficiently accurate as to be actionable in, say, a court of law.

It is not calibrated to a level that courts etc require as proof.

But at least it lets us Aston lot think we´ve got a James Bond car with secret capabilities, despite pretty much every other car on the road having an OBC too

Thanks for typing up the Manual too Luna....I quite like pages 78-105 if you wouldn't mind, old chap

[johng39]

Lunablack said:

As I said, I can only go on what Rick told me...... He said that he could see revs against engine temp.... Max revs, max speeds and lots of other stuff....

Maybe he was full of BS after all........ But I believed him, because, I do allow proper warm up etc...



There is also a section in my manual that says..and I quote


"DATA RECORDING"
Computers in your vehicle are capable of recording detailed data, potentially including but not limited to information such as

1. The use of restraint systems including seatbelts by the driver and passenger
2. Information about the performance of various systems and modules in the vehicle
3. Information related to engine, throttle, steering, brake or other system status

Any of this information could potentially include information how the driver operates the vehicle, potentially including but not limited to information regarding vehicle speed, brake, throttle application or steering input.

This information may be stored under regular operation, in a crash or near crash event.

This information may be read and used by:
1. Aston Martin
2. Service and repair facilities
3. Law enforcement or government agencies
4. Others who may assert a right to obtain your consent to know such information..



So is the info available or not??? The manual seems to suggest that it is

Edited by Lunablack on Tuesday 28th August 22:45

Impossible to store all of the data recorded in a car for all of the driving over the lifetime of the car without a serious amount of memory. All of the variables against time, it would be in Tbytes, not the few hundred Kbytes of memory that is in an ECU to hold these logs.

As discussed, when an event happens, then certainly a snaphot of data is held, but to continually monitor and store data ad-infinitum is not practical, without a massive hard drive to capture it.

[aMb]

I understand the Porsche DME records the amount of over revs across 6 rev ranges, i.e. range 1 is 7300-7500rpm and so on etc, and this is something the dealer look at before granting the extended warranty and guess can be used to determine how sympathetically a car can be driven. Assume the Aston does no such thing!

[johng39]

aMb said:

I understand the Porsche DME records the amount of over revs across 6 rev ranges, i.e. range 1 is 7300-7500rpm and so on etc, and this is something the dealer look at before granting the extended warranty and guess can be used to determine how sympathetically a car can be driven. Assume the Aston does no such thing!

I hope not or mine would store masses of data

[mikey k]

johng39 said:

Impossible to store all of the data recorded in a car for all of the driving over the lifetime of the car without a serious amount of memory. All of the variables against time, it would be in Tbytes, not the few hundred Kbytes of memory that is in an ECU to hold these logs.

As discussed, when an event happens, then certainly a snaphot of data is held, but to continually monitor and store data ad-infinitum is not practical, without a massive hard drive to capture it.

I agree but there is a simple solution we use is a 7 day rolling logger on our kit
Datsun do it on the GTR
IIRC the AM dealers can request a similar "black box" from the factory.
They fit it, you drive around, the fault happens and the box tells them what it did - magic!

Edited by mikey k on Wednesday 29th August 14:17

[NoahDav]

Same thing has happened to me, well while driving my engine would cut out, I tried to checked it. Engine lights was working properly. Checked the fan belt and it was slipping. I was suggested to replace it installation was not that easy but was okay since I had the Repair Manual. Other things to check are your fuel pump or the ignition system and ECU. It could also be caused by an coil pack failure.

Edited by NoahDav on Tuesday 18th September 03:57