Db9 exhaust manifold removal
Discussion
Hi Craig
My DB9 is still suffering from a lumpy idle and runs rich, it's a long long story.......
It all started last winter straight after replacing the coilpacks/plugs /pcv job, I checked and re-checked everything and could not find a fault,
I went to an AM Specialist garage, they diagnosed it but unfortunately could not find the fault, It was diagnosed the secondary bank has a vacuum leak, unmetered air that is causing a rough idle and rich running,
The primary bank runs 98% to lambda 1 and secondary bank runs at 80% to lambda 1, this is very close to triggering an engine light so i'm reluctant to drive it as I don't want to cause any further engine damage, but my emissions warnings have all been disabled as it had the primary cats removed a couple of years ago.
In desperation in August I replaced the secondary inlet manifold together with a new gasket, bolts and injector o-rings, still no change!!
Since then the car has been in my garage as I had bigger issues to deal with, so now I'm going to perform a smoke test on the engine, this pumps smoke into all the pipework from the airfilter all the way to the cylinder head, fingers crossed I'll find a leak somewhere to end this saga.
If anyone else has had this problem please let me know.
BTW, I had a look at my car last night, the rear cat downpipe just after the cat are cut and a flange is welded on, this must be the only way the exhaust manifold can be removed from the car, photo -
This was taken on the secondary side
My DB9 is still suffering from a lumpy idle and runs rich, it's a long long story.......
It all started last winter straight after replacing the coilpacks/plugs /pcv job, I checked and re-checked everything and could not find a fault,
I went to an AM Specialist garage, they diagnosed it but unfortunately could not find the fault, It was diagnosed the secondary bank has a vacuum leak, unmetered air that is causing a rough idle and rich running,
The primary bank runs 98% to lambda 1 and secondary bank runs at 80% to lambda 1, this is very close to triggering an engine light so i'm reluctant to drive it as I don't want to cause any further engine damage, but my emissions warnings have all been disabled as it had the primary cats removed a couple of years ago.
In desperation in August I replaced the secondary inlet manifold together with a new gasket, bolts and injector o-rings, still no change!!
Since then the car has been in my garage as I had bigger issues to deal with, so now I'm going to perform a smoke test on the engine, this pumps smoke into all the pipework from the airfilter all the way to the cylinder head, fingers crossed I'll find a leak somewhere to end this saga.
If anyone else has had this problem please let me know.
BTW, I had a look at my car last night, the rear cat downpipe just after the cat are cut and a flange is welded on, this must be the only way the exhaust manifold can be removed from the car, photo -
This was taken on the secondary side
Edited by paulrog1 on Friday 23 December 11:17
MarkwG said:
NMNeil said:
LTP said:
Craig elam1 said:
Although i am having second thoughts about the whole thing now i'm on the radar at "Team America"
Just keep your hands where he can see themSo insurance may be void, MOT failures and generally poisoning the air, just so the OP can.....well why does he want to remove something designed to keep the air breathable?
Edited by NMNeil on Friday 23 December 23:53
NMNeil said:
MarkwG said:
NMNeil said:
LTP said:
Craig elam1 said:
Although i am having second thoughts about the whole thing now i'm on the radar at "Team America"
Just keep your hands where he can see themSo insurance may be void, MOT failures and generally poisoning the air, just so the OP can.....well why does he want to remove something designed to keep the air breathable?
Edited by NMNeil on Friday 23 December 23:53
db9 was produced with 6 converters 4 small ones in the manifolds and 2 large ones halfway down the exhaust system.
Gas conversion takes place in the 4 manifold converters the 2 large ones do next to nothing,
In order to achieve exhaust gas recirculating without pipe work and associated valves etc AM decided to use a large valve overlap to produce “internal egr”.
This is fine until a misfire develops on one or more cylinders which can be completely undetected whilst driving.
The unburnt fuel from the misfire exits the exhaust port straight onto the face of the converter where it auto combusts.
Small fragments of rock hard ceramic material breaks off and as a result of the egr system
enters the cylinders where it begins to grind the cylinder walls and pistons making its way past the rings into the sump oil where it finishes destroying a £25,000 engine.
So removal of the primaries prevents this and gas conversion is carried out successfully by the up until then almost unused large secondaries emissions are unaffected.
A gentlemen who was involved in the development of our AM engines has confirmed that this is the case.
I still might sack this job off , not because of the global outrage but because it’s a difficult task and fitting a set of Ngk coils and plugs every few years is a lot easier!
So happy Christmas to you all in the UK and especially to my overseas friends trying to keep me on the straight and narrow
Gas conversion takes place in the 4 manifold converters the 2 large ones do next to nothing,
In order to achieve exhaust gas recirculating without pipe work and associated valves etc AM decided to use a large valve overlap to produce “internal egr”.
This is fine until a misfire develops on one or more cylinders which can be completely undetected whilst driving.
The unburnt fuel from the misfire exits the exhaust port straight onto the face of the converter where it auto combusts.
Small fragments of rock hard ceramic material breaks off and as a result of the egr system
enters the cylinders where it begins to grind the cylinder walls and pistons making its way past the rings into the sump oil where it finishes destroying a £25,000 engine.
So removal of the primaries prevents this and gas conversion is carried out successfully by the up until then almost unused large secondaries emissions are unaffected.
A gentlemen who was involved in the development of our AM engines has confirmed that this is the case.
I still might sack this job off , not because of the global outrage but because it’s a difficult task and fitting a set of Ngk coils and plugs every few years is a lot easier!
So happy Christmas to you all in the UK and especially to my overseas friends trying to keep me on the straight and narrow
NMNeil said:
https://www.gov.uk/government/publications/modifyi...
So insurance may be void, MOT failures and generally poisoning the air, just so the OP can.....well why does he want to remove something designed to keep the air breathable?
You seem to be getting your knickers in a twist over something you don’t understand. So insurance may be void, MOT failures and generally poisoning the air, just so the OP can.....well why does he want to remove something designed to keep the air breathable?
Edited by NMNeil on Friday 23 December 23:53
AMs generally have two sets of cats. Primaries in the exhaust manifold and secondaries downstream. IIRC this is to comply with some specific markets (California?) but was implemented generally for all markets for production line convenience. The cars will pass U.K. emissions tests with just the secondaries or just the primaries. AM itself sold some models with just the primaries (eg late model Vanquish S).
BlackWidow13 said:
You seem to be getting your knickers in a twist over something you don’t understand.
ASE Master TechnicianCalifornia Air Research Board (CARB) certified
Licensed G2 vehicle emissions inspector in the state of Nevada.
Worked for the Nevada DMV emissions compliance department from 2002 to 2005.
And you?
NMNeil said:
BlackWidow13 said:
You seem to be getting your knickers in a twist over something you don’t understand.
ASE Master TechnicianCalifornia Air Research Board (CARB) certified
Licensed G2 vehicle emissions inspector in the state of Nevada.
Worked for the Nevada DMV emissions compliance department from 2002 to 2005.
And you?
Qualification reveal;
QRE - Qualified Retirement Expert.
Engineering experience - Mole Wrench & Torque Wrench Useage; Level One, Pass.
You will therefore understand why I just ask the questions.
Might the rules about emissions be different in the UK from USA?
Never retrospective here in the UK.
Therefore my Vantage is not required to have any cats in the manifolds (headers).
The single pair of cats look externally, entirely OEM.
MoT test emissions results, are always well within allowable tolerances.
Is there anything legally wrong, if (purely as an example) the cats innards were not to be quite OEM ?
Terrible winter weather in the USA now. Hope you are safe and keeping warm.
NMNeil said:
ASE Master Technician
California Air Research Board (CARB) certified
Licensed G2 vehicle emissions inspector in the state of Nevada.
Worked for the Nevada DMV emissions compliance department from 2002 to 2005.
And you?
Fully conversant in the intricacies of primary and secondary cat deletes in England for V12 Gaydon era Aston Martins. California Air Research Board (CARB) certified
Licensed G2 vehicle emissions inspector in the state of Nevada.
Worked for the Nevada DMV emissions compliance department from 2002 to 2005.
And you?
Which is what the thread is about, I think you’ll find.
I’m not saying your qualifications aren’t impressive. More that they don’t mean a lot in this particular conversation.
NMNeil said:
ASE Master Technician
California Air Research Board (CARB) certified
Licensed G2 vehicle emissions inspector in the state of Nevada.
Worked for the Nevada DMV emissions compliance department from 2002 to 2005.
And you?
This is a UK based car though? It will be subject to an annual MOT and would pass if the primary or secondary cats removed. Even Works offer a secondary decat option for the V12 which they wouldn’t do if this was illegal. California Air Research Board (CARB) certified
Licensed G2 vehicle emissions inspector in the state of Nevada.
Worked for the Nevada DMV emissions compliance department from 2002 to 2005.
And you?
California emissions laws are well known for being very strict. There is no read across to the UK.
BlackWidow13 said:
Fully conversant in the intricacies of primary and secondary cat deletes in England for V12 Gaydon era Aston Martins.
Which is what the thread is about, I think you’ll find.
I’m not saying your qualifications aren’t impressive. More that they don’t mean a lot in this particular conversation.
My response was not about the technical aspect, but about the legal aspect.Which is what the thread is about, I think you’ll find.
I’m not saying your qualifications aren’t impressive. More that they don’t mean a lot in this particular conversation.
I have qualifications regarding the reason for emissions control equipment and how it works, but I have no qualifications or experience in actually illegally tampering with such equipment myself.
I'll have to rely on the practical skills of other PH members for that
As you will see above from my own totally original Vanquish S the car for Euro and other markets but not all doesn't have any secondary cats though they still use the same undertray with rhe cut outs for the standard vanquish which is fitted with secondary cats.
Some VH V12 cars left the factory with only 4 primary cats whereas others had 4 primary and 2 secondary.
So long as the gas readings are within the prescribed limits at testing I believe that's all that is legally required.
Dewi 2 said:
Qualification reveal;
QRE - Qualified Retirement Expert.
Engineering experience - Mole Wrench & Torque Wrench Useage; Level One, Pass.
You will therefore understand why I just ask the questions.
Might the rules about emissions be different in the UK from USA?
Never retrospective here in the UK.
Therefore my Vantage is not required to have any cats in the manifolds (headers).
The single pair of cats look externally, entirely OEM.
MoT test emissions results, are always well within allowable tolerances.
Is there anything legally wrong, if (purely as an example) the cats innards were not to be quite OEM ?
Terrible winter weather in the USA now. Hope you are safe and keeping warm.
https://www.epa.gov/enforcement/clean-air-act-vehi...
And thank you for your concern about the cold here. -14c here last night, but my heat pumps are coping admirably. Whisky and weed helps you not notice the cold as well.
NMNeil said:
Dewi 2 said:
Qualification reveal;
QRE - Qualified Retirement Expert.
Engineering experience - Mole Wrench & Torque Wrench Useage; Level One, Pass.
You will therefore understand why I just ask the questions.
Might the rules about emissions be different in the UK from USA?
Never retrospective here in the UK.
Therefore my Vantage is not required to have any cats in the manifolds (headers).
The single pair of cats look externally, entirely OEM.
MoT test emissions results, are always well within allowable tolerances.
Is there anything legally wrong, if (purely as an example) the cats innards were not to be quite OEM ?
Terrible winter weather in the USA now. Hope you are safe and keeping warm.
https://www.epa.gov/enforcement/clean-air-act-vehi...
And thank you for your concern about the cold here. -14c here last night, but my heat pumps are coping admirably. Whisky and weed helps you not notice the cold as well.
So it's illegal to modify a car such that it no longer complies with the emissions it was originally certified with; it does not say you cannot modify at all.
NMNeil said:
No, it's illegal to remove or tamper with any emissions controller equipment in both the UK, EU and the US. The US just has more enforcement of those laws.
https://www.epa.gov/enforcement/clean-air-act-vehi...
And thank you for your concern about the cold here. -14c here last night, but my heat pumps are coping admirably. Whisky and weed helps you not notice the cold as well.
So to clarify, it's illegal to remove primary cats even if the exhaust emissions remain within legal limits, but it's fine to smoke weed?https://www.epa.gov/enforcement/clean-air-act-vehi...
And thank you for your concern about the cold here. -14c here last night, but my heat pumps are coping admirably. Whisky and weed helps you not notice the cold as well.
Just want to make sure I'm not doing anything wrong.
MarkwG said:
That's not what the link you posted says - " it is an offence to use on a road a vehicle which has been modified in such a way that it no longer complies with the air pollutant emissions standards it was designed to meet."
So it's illegal to modify a car such that it no longer complies with the emissions it was originally certified with; it does not say you cannot modify at all.
As written, true. But if the car originally had type approval by meeting all the emissions requirements without those cats, why did they go to the considerable expense of fitting them in the first place?So it's illegal to modify a car such that it no longer complies with the emissions it was originally certified with; it does not say you cannot modify at all.
I'm sure if the OP removed the cats then had the car inspected to make sure it still only emitted a maximum of 0.3% CO at idle, 0.2% CO and a max of 200 PPM HC at fast idle it should be fine.
NMNeil said:
No, it's illegal to remove or tamper with any emissions controller equipment in both the UK, EU and the US.
Whisky and weed helps you not notice the cold as well.
I had a little chuckle Neil.
The topic talk touches on emissions illegalities, but then you mention weed.
Not exactly sure what your weed might be, my lawns have far too many, however in the UK, I have heard some kind of illegal drug being referred to as weed.
I am sure that my association must be completely muddled, because a retired policeman would be assiduously complying with every law.
I must buy you a
the next time I visit the USA.Have you ever had the opportunity to tour the Gaydon factory?
One probably completely unrelated (although not if you travel to England) current news item, is the UK Border Force are now on strike.
Chaos was expected at airports.
Military people have taken over and passengers at Heathrow and Gatwick Airports, say they have never experienced such an efficient operation before. Suddenly there are no queues and the military staff are said to be very efficient, helpful and polite, as well as earning less than the people they have replaced.
The union leaders must be furious. Looks as though the Border Force employees might have been found out.
Edited by Dewi 2 on Saturday 24th December 17:54
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