2005 3.0V6...irritating misfire...cant seem to solve it

[Vladster]

this is getting irritating.

I have a 2005 3.0V6 with 62k on the clock.

Car has developed a slight misfire and engine management light eventually comes on.

Garage have diagnosed that there is a misfire on bank 1 across all 3 cylinders.

Car has had new spark plugs and coil packs and leads have been swapped from bank 2 to 1 and misfire remains on bank 1

Fuelling appears to be all over the show.

Vacuum lines have been smoke tested...no leaks found.

Out of desperation I've also got the garage to fit 2 new DENSO lambda sensors as I've had problems with Lambda sensors on previous Jags with the V6 petrols.

Thoughts...if it was failing MAF, surely the faults would occur across both banks as there isn't a MAF for each bank.

So what's causing the fuelling to be all over the place???....any thoughts would be gladly received.

Thoughts now...potentially a blocked CAT

 

Quote 

[Russ68]

Hey Martin, sorry to hear your issues, sounds irritating! I had a similar issue that was solved by x6 OEM spec plugs and coil packs, ran like a dream afterwards. But as you've done this, and you're fuelling is all over the show, fuelling would seem to be where to look. Do injectors go and could these be the culprit? I know diesel injectors need replacing periodically, not sure about the petrol S.

Good luck with it anyhow, hope you get it sorted 😉 

  

[Wrinkly]

On 10/28/2021 at 8:10 PM, Vladster said:

this is getting irritating.

I have a 2005 3.0V6 with 62k on the clock.

Car has developed a slight misfire and engine management light eventually comes on.

Garage have diagnosed that there is a misfire on bank 1 across all 3 cylinders.

Car has had new spark plugs and coil packs and leads have been swapped from bank 2 to 1 and misfire remains on bank 1

Fuelling appears to be all over the show.

Vacuum lines have been smoke tested...no leaks found.

Out of desperation I've also got the garage to fit 2 new DENSO lambda sensors as I've had problems with Lambda sensors on previous Jags with the V6 petrols.

Thoughts...if it was failing MAF, surely the faults would occur across both banks as there isn't a MAF for each bank.

So what's causing the fuelling to be all over the place???....any thoughts would be gladly received.

Thoughts now...potentially a blocked CAT

 

Quote 

Martin

I have a 2005 2.5 V6 petrol with 62,000 miles and have been through the very same experience as you describe. I am not categorically stating that my problem is the solve of your issue, just posing it as "food for thought".

Have replaced all six ignition plugs and ignition coils, along with new upstream and downstream Lambda`s, had smoke test, new exhaust manifold gaskets (6), all OEM specification etc. etc. After the misfire, which was only on one cylinder (No3 in Bank 1 ) all went well for a couple of weeks. Then the code P0420 started appearing and would reappear after being cancelled. This indicated a Catalytic Converter problem on Bank 1. Eventually had the car up on a lift and found that the pipe from CAT on Bank 1 was, if tapped heavily with a fist, making a rattling sound as though as though full of bits of rubbish. A very experienced technician that was with me immediately knew that this was a bad CAT that was causing the Yellow Engine Warning Light and Code P0420. He had seen it many times before. 

It is apparently known that a misfiring engine can eventually "kill" a CAT, which my thinking is that it has happened to mine.

None of the usual signs of CAT failure (high fuel usage, engine not running smooth, smell from the exhaust of rotten eggs etc etc) were present.

I have now purchased a new Catalytic Converter (along with necessary fitting kit) and will hopefully this coming weekend be fitting the new CAT.

Will report back on this matter once CAT is fitted and run for the 18 - 20 miles that it usually takes to make the P0420 code appear.

 

Hope this may help in some fashion or form and good luck with resolving your issue.

All the Best and Regards, John

[Wrinkly]

On 11/10/2021 at 2:28 PM, Wrinkly said:

Martin

I have a 2005 2.5 V6 petrol with 62,000 miles and have been through the very same experience as you describe. I am not categorically stating that my problem is the solve of your issue, just posing it as "food for thought".

Have replaced all six ignition plugs and ignition coils, along with new upstream and downstream Lambda`s, had smoke test, new exhaust manifold gaskets (6), all OEM specification etc. etc. After the misfire, which was only on one cylinder (No3 in Bank 1 ) all went well for a couple of weeks. Then the code P0420 started appearing and would reappear after being cancelled. This indicated a Catalytic Converter problem on Bank 1. Eventually had the car up on a lift and found that the pipe from CAT on Bank 1 was, if tapped heavily with a fist, making a rattling sound as though as though full of bits of rubbish. A very experienced technician that was with me immediately knew that this was a bad CAT that was causing the Yellow Engine Warning Light and Code P0420. He had seen it many times before. 

It is apparently known that a misfiring engine can eventually "kill" a CAT, which my thinking is that it has happened to mine.

None of the usual signs of CAT failure (high fuel usage, engine not running smooth, smell from the exhaust of rotten eggs etc etc) were present.

I have now purchased a new Catalytic Converter (along with necessary fitting kit) and will hopefully this coming weekend be fitting the new CAT.

Will report back on this matter once CAT is fitted and run for the 18 - 20 miles that it usually takes to make the P0420 code appear.

 

Hope this may help in some fashion or form and good luck with resolving your issue.

All the Best and Regards, John

New Catalytic Converter fitted yesterday. Quite a lot of destroyed rubbish found in the old one. (Photo attached). Code reset and has so far completed sixteen miles and no yellow management light as yet. On previous times of resetting the code it has taken up to 18-20 miles to regenerate. Fingers crossed this time. The moral of this story may be, I should not have spent time and money attempting to deal with the P0420 Code by cheaper methods first. I.E. new sensors upstream and down stream, smoke testing, checking all joints etc etc. Followed lots of sound and helpful advice but eventually had to "bite the bullet" and buy the new Catalytic Converter. Not to worry, hopefully job done now.

 

 

[Wrinkly]

Now covered 28 miles and no Yellow Engine Management Light as yet. Usually reappears, after being reset, in between 18-20 miles. Fingers crossed it may be cured/fixed.

Beat Wishes, John

[Vladster]

On 11/17/2021 at 9:31 AM, Wrinkly said:

Now covered 28 miles and no Yellow Engine Management Light as yet. Usually reappears, after being reset, in between 18-20 miles. Fingers crossed it may be cured/fixed.

Beat Wishes, John

Thanks John for your updates....I'm hoping to get the mechanic to see if the cat is blocked.

Just out of interest where did you purchase your CAT and how much did it cost?

[Wrinkly]

Martin

I feel your mechanic is going to struggle to see if the CAT is, as you put it "blocked", without removing it, which is not a simple five minute job. He may however be able to hear, by tapping it heavily with his fist, if there is any debris in there. If it were "blocked", I somehow doubt that the car would run very well, if at all, if it was "blocked." Just to remind you, my car was running extremely well and had no signs of what is often associated with a knackered CAT. It took me a lot of trial and error to get to the root problem and I now wish I had (with hind sight) changed the CAT in the first place instead of investing time and money in trying other parts first kin the hope of saving some money. This I did not achieve. It is easy with hind sight, is it not ????????

I have attached a link to where I bought my new CAT and for information it was £170 , you may also need to acquire a fitting kit which will cost around £12. The supplier of the CAT that I bought does not sell fitting kits but there are plenty on eBay.

With both the CAT and the fitting kit be warned that there are two different ones fitted to 2005 cars. You will need to have established which your car has and it is best to provide your chosen supplier with the VIN No. for your car. There are cheaper CAT`s available on eBay but you will have to be aware of quality and warranty. I was personally not satisfied with answers to questions I posed to the cheaper suppliers. There again though, I am a great believer in, "You only get what you pay for". I am by no means suggesting you should take the same approach and that of course is, rightly so, your decision to make.

https://www.onlineautomotive.co.uk/car-parts/Jaguar/S-Type/2.5L/Petrol/Premium/Exhausts/Catalytic-Converters/JAG1036H/1/34#

Good luck with correcting your cars problem.

Regards and Best Wishes , John