Have had the car for two years and recently noticed a metallic clacking (cant think of a better word) noise from the engine under high revs. It happens at 4-4500 rmp and over when I press the accelerator. Spoke to a Jag indy yesterday and was a bit wolly trying to explain what was happening so I brought it for a run last night to try and get a handle on what was actually happening. Went manually into 4th at 4500 rpm and clacking started, revs were not stable with a slight flicker in the rev counter hand . 10 seconds later flashing engine management light and 'restricted performance'. Slowly went home, car obviously under powered. Started and drove (not at speed) this morning with no issues. Had the codes read by a local mechanic - P0504 P0302 P0304 P0306 P038 P0300 U0104 along with some emissions errors. He's of the opinion it could be a mechanical fuel pump given the noise and performance issues but readily admits he's not an expert on those cars. Any ideas?

 

Have you checked what these codes mean ?

P0302/4/6/8 mean misfires on cylinders 2,4,6 & 8. P0300 means random misfires. If you see your CEL flashing, it means that damage is being done to your catalytic converter(s). So I wouldn't be driving it - cats are expensive.

As to the cause, you need it diagnosed step by step. There are threads on here with similar problems, so do a quick search.

 

BTW, sounds like you need to change garage as this is straightforward troubleshooting & you've got the same engine as the STR. As you're around Manchester way, why not ask for an indy recommendation from the UK site ? Just a thought.

www.jaguarforum.com

 

Cheers for the reply. O have it booked in with Jagman in Wigan for the 21st. Just trying to get a handle on what it might be and how serious it is. Money's tight right now with Corona lockdown.

 

I know what you mean. Good luck.

 

You've got a choked catalytic converter on bank two.

 

Maybe also a fuel rail issue on that bank

 

That's interesting you say that. There is a (or so I though) separate issue that predates this with the catalytic converter. The garage (not Jagman) said there was an "inefficiency" but that it wasn't an issue and they'd just live with it so I did. These cars are like hens teeth in the UK and a new cat a difficult and expensive find. Are there any other models that use the same cat?

 

Jaguar don't make the cats, they buy them & sell them to you at an increased price. If your indy is worth his salt he'll be able to get a match from another place that's not Jaguar. Explain it to them when you get there.

 

So trying to get my head around whats happening, is the clacking noise I'm hearing the misfire?

 

When I brought it up last service the chap just rang Jag for a price for a new cat, no after market option was mentioned. There aren't too many SV8 in the UK, does that cat fit any other car/Jaguar model? Is it the same as on the early Type R or any other? Cheers everyone.

 

Misfires or detonation, basically there are hot exhaust gases remaining in the combustion chamber because the exhaust is choked up on that side.

I've been there done that on two of my own cars, and several other cars as well.

Just find a pair of aftermarket "Euro 4 compliant" cats and get an exhaust shop to cut out the old ones, weld the new ones in.

 

Sounds like a broken up cat. Probably on the side shown by the codes (bank 2). Pity they're very costly!

 

My cats melted out last year, I had an exhaust shop that cut them out and weld in high flow performance ones instead, it cost less for the pair than Jaguar wanted to charge for replacing one. But still not cheap. Upside - it made it sound a bit meatier.

 

Two different Jag indies have advised against that, they both said I could well get emission codes.

 

Ok, cars been with mechanic since Thursday. He thinks the cat is showing a problem but it isn't causing the misfire. He says hes struggling to track down which cylinder it actually is as it isn't happening all the time, just under high revs/load. He thinks it might be an injector. All seems a little fuzzy right now.

 

Classic signs of a broken cat conv...

 

Ok, to update everyone. I took the car to a local independent Jag specialist. Was poor to be honest. he took it off me on a Friday and I didn't get it back until the next Thursday after I chased him up. Turns out he did two hours diags on it on the Monday and didn't bother to tell me to come and get it. He said he couldn't pin down which cylinder was misfiring and it was "probably" a blocked cat. He had said earlier in the week it probably wasn't the cat. Honestly he lost all interest when I didn't want to spend £1200 on a "probably". I asked him to uncouple the cat, I knew there might be sensor faults but we would at least see if a restriction in the cat was causing misfires. Uncoupling the cat should = no misfire if its a blocked cat right? Well, that's just not possible he said, noise smoke blah blah blah.

A clay shooting buddy is an automotive engineer, deals with Range Rovers and the like (he hates them with a passion). He recommended a young lady he gets (regularly) in to run diagnostics on the Range Rovers. She gutted the cats and sorted the ECU (not sure if it was a delete or a reset to Euro2 but its now working like a dream. Quite a bit noisier, we've gone from George Cloony to Vin Diesel but no misfires. Cheers everyone for the advise.

 

Ok, final update. The cats have been bored out and the problem has gone away. To those who pinpointed a blocked cat, you were right. Thanks everyone for the help and advise.

 

Oh, and this guy was an idiot! Wasn't interested in actually resolving the problem.