Janspeed manifolds and horrible fuel consumption !
 

Recently fitted some janspeed manifolds and loving the sound! Tho power has gone down very slightly :-( and since fitting fuel consumption has gone terrible!! The only thing I can think is a I've damaged one of the sensors possibly, or I've been told a few people have found that the fuel as gone down like that after fitting new engine parts for a short time while the ecu adapts. Any thoughts or anyone else who's got janspeed manifolds who have had similar?!

You're driving it faster...?

Have you just got the mamifolds or complete system with sports cat? I have the whole system and mine has improved on power and consumption is no worse. You may have a lambda issue, do you have engine management light on yet? It took a couple of days before mine lit up!

Possibly lambda but yes, you can reset fuel adaptions on t4

How can you do that?? I've not got a sports cat its currently got a decat too, not driving it any faster?? Might fit some new sensors see what happens. Engine light is on but thats been on since the decat, might get a mil light. Was there a guy on the forum selling those?

There was but he's a lazy fuker and doesn't do them anymore. :whistle:

Downstream oxygen sensor does nothing for fueling its just a monitor, the upstreams do affect fueling a massive amount, may find the wiring is damaged to on of them, if you unplug them it should go to default fueling, if it starts driving with more power can bet one of them is down, resetting the adaptaions needs done through the T4 diagnostic computer. Check your stored codes first, anything related to bank 1 sensor one or bank 2 sensor one you can bet its related

Cheers for the info bud appreciate that :-)

Bank 1 sensor 2 - no activity?

that's my reading, isn't that the upstream post cat sensor?

As said. You need to read the codes as the de-cat Mil could be masking a damaged primary O2 sensor.
In the days before closed loop mixture control fitting a free flowing exhaust system improved fuel consumption. Sadly since the Green Party own goal this isn't the case so much now. It shouldn't be worse on fuel though.