Were the mini cats the 200 cell cats you bought? Or did you bypass the rear cats?

 

"Mini cats" are extension tubes containing cat cells that are inserted into the rear O2 sensor hole with the actual O2 sensor screwing into this extension to avoid any MIL error.

So I installed the Paramount 200 cel sport catalytic converters and then the mini cats.

Thats when the discussion went into the facts about the minicats causing extra
rich fueling at high throttle openings.

I definitely do not want that so I took out the mini cats and will live with MIL warning light if and when It comes up. I will clear it tho when it happens.

To get thru emissions I will re-install them. No big deal.

Plus if and when the ECM tune that Cambo is working on comes out AND IF I can install it I should be very good indeed.

 

"Or did you bypass the rear cats?"

There are no rear cats in these cars, 2 in total ( one for each bank of the v ).

 

Trust me - get rid of those horrible things , they are restrictive when new and when thay start to fail they are like a brick wall biult into the exhaust system .
Not at all what a performance engine needs .
I haven't seen a MIL at all yet in 3-4000km with 200cell cats . So it hardly worth worrying about . I'm starting to wonder though if the STR tune is more resilient to the sports cats than the XJR?

 

I don't see how it could be, the factory file that get's loaded into the ECU is exactly the same for the XJR & STR, exact same file.

Unless it's something to do with the emissions settings, perhaps the FED (USA) emissions settings are more picky about the Catalyst Efficiency than the Euro3 which is loaded in the UK-spec cars.

 

Could be somthing in that mine is ex Japan .
How long does it normally take two flag a MIL for cats ?
I thought if it was going to it would have by now ,
Also don't want to speak to soon .

Mine is monitoring 8 items
And I'm certain one of the is catalytic converters.

 

Varies but why not read the pending code?

 

1st 230 miles driving from MD to MA no problems even a couple of wot runs.

Stopped to fill up with gas. As soon as I started the engine "Restricted Performance" shows up along with orange engine icon.

Driving was ok like that tho.

This morning I read and cleared just the one code P0174 no other codes.

Drove a few miles to get shopping no problem. On the way back tries a wot run and the engine stumbled really badly and again "Restricted Performance".

Why only one bank ?

Not feeling too good about these 200 cel cats to say the least. I am running without the mini cats.

Oh on a good wot run in that 1st 230 miles I could actually see smoke out the back lit up by a cars headlights. Quite a bit.

 

Sorry to hear your problems...
P0174 is running lean on one bank, the cats shouldn't cause this. The cats should bring up a P0420 'Catalyst Efficiency' code.

 

Could it be an O2 sensor. Maybe I should swap the lhs ones to the rhs and see whether the fault follows?

I was not having a problem before switching the cats.

 

Could be the lambda sensors, yes maybe you could try swapping them over.

 

Bugga , It could also be an exhaust flange leak just above the cat , seen as thay have been disturbed . I'd be checking there ,

 

I have read the pending code , it's p1111

 

Good point. I used a "non standard" stud on one flange due to a cross threaded nut. I have one on order.

So in a couple of weeks will 1st try redoing both flanges after that if there is still an error swap sensors and go from there.

I am in MA and do not have the ramps etc. that are down in MD.

 

Maybe a badly-fitting cat letting in air thus the P0174.

 

Problem solved. Just did several wot runs and spun the wheels even in a rolling start.

I remembered the check engine lite coming on after I fitted an oil catch can to the high load side because of a leak.

So I took it out.

No problems now.

So much ado about nothing in the end.

Just cannot get a good seal into the high load breather pipe and I do not want to damage it.

 

Good to hear Jackra...Do you notice a difference in power?

 

Very noticeable increase in power. Wheel spin like never before even after a long rolling start.

 

I bet your quest to 450 HP is getting close! Intake 10, pulley 15, cats 20, misc. cooling improvements Add Cambo's tune and your there or more!

 

I think adding the 200 cel cats "enabled" the previous mods I made.