What did you do to your x40 today???

[V40T4R]

Originally Posted by gazO2V40T4

Peak boost should be at 14psi and then tail off

Absolutely!

[gazO2V40T4]

Originally Posted by clarkey1984

Cheers guys, I've not got Vida dice or anything, but it is on my to do list as it'll be very handy in general, and although I haven't tried it I doubt the generic gendan reader will work with it, my workmate tried it on his 2002 VW golf and it said lean condition bank 2.. on a 4 cylinder haha.

And no it still boosts fine, I'm not sure on bar as my gauge doesn't have bar on but it hits 10 psi at peak, although has always started to drop off very slightly once you reach about 4000 rpm, although I rarely take it much higher than that for any length of time as it pulls so well lower down there's not really any need to, and I'll try the carb cleaner idea to see if anything shows up

Check the diaphragm in the oem recirc valve on the turbo and also the vacuum pipe from the recirc valve to the turbo it’s only about 6inchs long and can go unnoticed also make sure it’s clamped this could be part of the reason the boost is only at 10 psi also the wastegate might not be fully closing so check the actuator rod isn’t loose as the eye that connects to the wastegate can go oval which will also not fully clos the wastegate

[clarkey1984]

I'll check all of these out over the weekend, although I'm suspecting the accuracy of my boost gauge now, because the car goes like absolute stink, no way it's 4 psi down from standard, it flies, knocks spots off the E36 328i I had and that was well over 200bhp.

[Antz]

Originally Posted by clarkey1984

I'll check all of these out over the weekend, although I'm suspecting the accuracy of my boost gauge now, because the car goes like absolute stink, no way it's 4 psi down from standard, it flies, knocks spots off the E36 328i I had and that was well over 200bhp.

Definitely worth checking it with another boost gauge and checking the vac lines. Even when mine was in limp mode with 0.5 bar of boost it felt quicker than my E36 328I does but its a linear thing. The T4 throws you back and feels quicker whereas the BMW 6 pot is a smooth pull.

[clarkey1984]

I've just tested with the maf disconnected which definitely gave me limp mode, 5 psi max boost, reconnected it and aside from the EML now being on back to 10 psi, so even more certain that it's the guage.

[gazO2V40T4]

Took the T4 for its mot retest and now it’s back on the road so next up a big clean and drive it for a bit and try to get the wife to let me keep it

[MartinPorter]

Originally Posted by gazO2V40T4

Took the T4 for its mot retest and now it’s back on the road so next up a big clean and drive it for a bit and try to get the wife to let me keep it

easy to pass the MOT..... then the Mrs!

[gazO2V40T4]

Originally Posted by MartinPorter

easy to pass the MOT..... then the Mrs!

Yeah deffo agree with that comment 😤

[clarkey1984]

Goodbye agent orange, you've been a bloody trooper of a car, a really nice Portuguese fella bought it, the excitement on his face when he started her up was really good to see, he's going to enjoy that car.

[canis]

I changed the throttle position sensor. It is much better now, much more responsive with no flat spots.

It hasn't solved the engine management light though. It still lights up if it is left ticking over for a few minutes. Can't figure out why.