DB9 Engine Misfire

[@7.92Gav]

Hi Mike, thanks for another great video. My ‘05 DB9 with new coils, plugs & PCV valves still has misfires at idle only. When driving it is a dream. The misfire monitor shows few misfires but not attached to any specific cylinder. Should I revisit this or is an idle only misfire less likely to cause damage?

[@BamfordRose]

Like in my vid where I show AMDS plotting each individual cylinder / misfire, what’s that plot on your car look like? Is it counting up misfire type A? Or just B? Some v12’s for whatever reason, which is not any defective component, do count up low level misfire at idle, which immediately ceases the moment engine speed is increased slightly. So if off idle your engine is not recording any misfire whatsoever, that’ll be fine, but, the level / magnitude of misfire at idle does need to be quantified.

[@7.92Gav]

@@BamfordRose Thank you Mike. I can feel the idle misfire, but no torque tube rattle and the exhausts 'pop' every few seconds on idle. I'm using the Foxwell NT520Pro but have never recorded a P0300 series DTC. I am currently unsure which type of misfire I have, but am I right in saying that type-A misfire can be recorded as $80 and type-B as $81 ? The car is currently in storage but hopefully back for April and I will start proper recording of the misfire data. If only I lived in England and could bring it to you!

[@stevejordan103]

Exactly why I had you decat my car with your manifolds so I don't have to worry about Catalyst failures, plus it goes better too..😁

[@neildutot4246]

Definitely going to get to Bamford Rose ASAP to get rid of the Primary Catalysts this possible problem scares the crap out of me. If ever you do pick up a misfire a long way from home at least you can drive the car without worries.

[@nakmas73]

Mike, I’m a massive fan, as you know cos I’ve been up to see you a few times in my 133,000 mile db9. But I do have to wonder as to the warning light on the dash on your test car 🤓

[@markchip1]

At 20:55, didn't you mean to say "you can take off the EXHAUST manifold and clean out any debris...", instead of the INLET manifold?? Or can it be either? I had understood that the cat fragments were being drawn backwards into the combustion chambers.

[@BamfordRose]

Hi Mark. No, what I said is correct! The catalyst failure / debris in exhaust port gets sucked back into a combustion chamber, then gets sucked into the inlet manifold, and then distributed to all cylinders on that side of the motor. So if a cat failure has occurred and someone simply renews the cat, and they do not check for remnants of the old failed cat glued to the walls of the inlet manifold via oil film, that oversight (which I’ve seen time and time again, from both independents and franchised) risks failing the motor as the debris gradually comes off the inlet manifold walls and into the cylinders

[@fabioalemanno1841]

Hi Mike, thank you for your video, it's quite clear for me and my poor English. I watched that because also my car suffer for some misfire but I didn't understand (me and the local service team) the cause; the scenario is only related to the cylinder 2 , only in idle, only when the engine temperature (oil) is greater then 80 °C (in this situation the misfire counter increases quite quickly, more or less 100/150 per minute). When not in idle the engine runs very well. To complete information: Coils and sparks are new and cilynder compression is fine. Could be something related to the Lambda sensor? Thank you in advance for you answer, Fabio

[@12345GAOTau]

What’s the cost of the de cat with yourselves?

[@willemvermeulen7000]

Possible to make some more DB7 related videos

[@barryfarrell123]

Can the catalyst be moved down stream to prevent ingest … ie) headers ?

[@PAC9322]

👏🏽👏🏽👏🏽 well said 🥂

[@markgtrheyes]

Would love to remove the primary cats from my gen 1 vanquish, but quite a big job to get at them...

[@BamfordRose]

Big job on Vanquish is an understatement Mark. Your Vanquish will be fine, well cared for!

[@markgtrheyes]

@@BamfordRose Yes, she's still going strong, albeit only 250 miles in 2020..... looks very busy at BR!

[@arconcritter]

Hi Mike, In the videos about cat failure you seem to always be discussing this issue in reference to DB9 engines. Is this cat failure exclusive to DB9 or is it relevant to ALL the V12 engines in all models?

[@pascal-regisdelfosse1852]

Can the V12 Vantage S generation also experience this problem? Can you confirm that it is possible to remove the primary catalytic converter without causing problems (electronics, programming, abnormal wear of other mechanical parts, etc.)? Thanks

[@BamfordRose]

Yes, seen a few V12VS with failed cats. The problem can arise from any V12 with primary catalysts in the exhaust manifolds, so Not DB7, but is all other V12’s. The removal of the primary cat will not cause any other consequential errors / issues, apart from the ECU needs remapping so that the check engine / emissions light does not illuminate

[@pascal-regisdelfosse1852]

@@BamfordRose Thank you for your response. I particularly appreciate this V12, "bien né / well born". For my V12 VS, my intention is to make it "breathe" as well as possible, without harming the rest of the car or its value. Does this require changing the entire exhaust system? In one of your previous videos, I think I understood that the removal of the primary catalytic converter allows a power gain of 70 to 90 hp. Can the rest of the car's components withstand this gain? Do you carry out the necessary ECU reprogramming as you indicate? It seems to me that Aston Martin offers 2 packages, "Performance" and "AMR" which I don't quite understand the differences between them. These packs add ceramic intake manifolds, a carbon fibre rear diffuser with carbon fibre fins and a titanium exhaust system. What do you think of them? What could you offer me? Take care of yourself.

[@hirwn1120]

I can't find the reason for the misfire , i did full maintenance Still there Any advice?

[@jimgoodwin6294]

Whats the DB9tik?

[@vinceloe4996]

Is there any relationship between the dreaded engine tick and misfires?

[@BamfordRose]

Not really. An engine which is lightly ticking or majorly ticking, is not causing unburnt fuel (misfire) to go down exhaust pipe to catalyst, so a ticking engine is not at risk of failing the cat any greater than a non ticking engine

[@vinceloe4996]

@@BamfordRose I was thinking of it the other way round. Could missfires cause the onset of a engine tick? Great content as always! 👍