Hi there!
I just had some awesome straight through stainless steel pipes put in to replace the back boxes. She already has the centre cat cut out and a 3” through pipe fitted. Sounds and goes awesomely. She just got MOT pass .
then 50 miles later, she all of a sudden said “restricted performance “ and the Amber engine warning came on.
weird. I didn’t do anything else. She ran perfectly though, so I did not experience any restrictions.
anyone had this issue?
I can only assume maybe the ecu has now detected less back pressure. But I I don’t see that is an issue. So I’m baffled…. Sorry for the extremely bad joke!
cheers !

 

Please check for codes

 

I’m fed up of buying crap OBD readers. So cannot. That of course would have been the obvious answer. But I was rather hoping for feedback on someone who has done this replacement and experienced the same thing….

 

Recently I had a discussion here on the forum with someone who designed the X-Type in these regards. He pointed out how important the correct back pressure is.

Agreeing with Jim: We can all just be guessing without codes. So yes, by bet is also on the reduced back-pressure - that would have been my answer as well, if you had not written it yourself. And it may even be the case that if you had those codes that those would be the codes for the oxygen sensors - I could imagine that they deliver measurements now, which would be regarded as faulty in the OE system.

Well, I am not the one, who designed the engine transmission (just some switches on the X400 X-Type), thus this idea of mine may be stupid, but if it were my problem, I would try that: Maybe it is possible - just for testing purposes - to increase the backpressure on your Jag by restricting the size of the opening on the end of your tailpipe and see, if the restricted mode disappears.
But - then again - even if that would fix the issue for testing purposes, I would wonder, if the system would simply jump back to normal mode and cancel the restricted performance mode without you having a code reader, which would be required to delete the current failure code... I do not know the answer to that one as I would have used my reader to delete it. Frankly, I do not know how you intend to do fix any mysterious failure on your Jag yourself without code reader - it is either that or garage (where they would have a reader). But if you storm out now to buy one, do your homework first, which reader is a good one, as there are differences.

And other idea: My X308 was in restricted mode when I bought it. The seller had no idea what it was, which is why I got it cheap. I connected my code reader back home and it told me straight off that it was the knock sensor. Easy fix. Based on that I must also be wondering, if your engine "knocks" now differently with the system being altered and not being OE anymore - so that even with the knock sensor being intact, it would deliver incorrect readings...

Other than that: Yes maybe there is someone out there, who can tell you what also you have to modify away from original design intend to trick the X308 into thinking that everything is OK. Jags are very sensible and they do not like to be modified or changed, unless you change EVERYTING...: Like completely different engine and transmission and exhaust system... Everything is possible - but deciding, what is a good idea is difficult...

PS: Recently I saw a youtube clip from Harald Lesch. He is a very wise German man, who knows everything about everything and he produced a lot of scientific short clips for TV. The clip was (in German of course and) about the idea of e-fuels (Artificially made petrol, which draws CO2 out of the air during production) and electric cars and he said they when he made a public presentation/speech about that issue recently, someone from the audience approached him afterwards and said to him (translation): "Well, you know Mr. Lesch, I understand where you are coming from, but I am a stag - and for me it has to roar..."
And that left him (Harald Lesch) pretty much speechless... (This is a refence to: "She already has the centre cat cut out and a 3” through pipe fitted. Sounds and goes awesomely. ")

Ups, I see that only now... You removed the centre cat (catalyst) and expect your Jag to just purrrr on and pass the MOT???? This makes it even more likely that your have codes for false oxygens sensor readings...

 

Is it even legal (in the UK)?

 

Sophisticated cars. such as ours, often do not take kindly to modifications which alter the overall
configuration of the exhaust system. Pre 1972, we could slap on some headers, weld on some
glass packs and we were good to go. Not so with the intertwined detection sensors in these cars.
Short of reprogramming the ECU or providing more restriction to the exhaust system, you will more
than likely have to live with the uncertainty of that warning.

 

BLUF: review your work; I always suspect error on the part of the assembler whenever I hear how well it worked, "I did this or that" and now it is screwed up. Might be nothing more complex than a broken wire . . . loose connection at the downpipes . . . dirty throttle bore/plate and MAF.

 

Thanks for that.. she had her centre cat removed already.
every mot passes, because she still retains the 2 downpipe cats. Provided cats are still there and she passes the emissions test, it’s legally ok.
then I deleted the back boxes with the straight pipes.
MAF is new. Butterfly is clean. TPS recent.
running fine before back box delete.
Now I’m just guessing that with both adjustments… it’s pushed her too far and the lack of back pressure is messing up the ecu.
I took her out today and a couple of times she went on “failsafe engine mode” check engine light still on. It’s a pain but I will have to take her back to my mechanic to diagnose….then I think probably to put back the back boxes…

 

There is no center CATAVERTER on the North American X308.(don't know about the ROW)
There are 5 mufflers/silencers/resonators from the 'CAT(s) back'.

 

No centre cat on row either.

 

Daft idea - if you've got cruise control 'armed' so the light is on behind the gearstick, turn it off. That was the cause of my random failsafe modes the other year, because the second TPS was faulty.

It's a total guess without the codes though.

 

these are not sensitive to mods lol. people were slapping 2.6 kenne belles on and the stock tune was adapting to it 😂😂😂

your RP came on for an unrelated reason and if you don’t want to take it to someone who knows these cars i can’t help you 🤷‍♂️

 

She already said she was going to take it back to her mechanic, so let's see what he has to say
about her mods.