n75 wgfv.

[Monkeymagic]

I'm not sure if Jim's has tried it with Mfts unplugged the car is certainly not underpowered it just gets boost cut under load and gives 00544. Code I have ruled out boost leaks and moved onto n75 before finding it does not respond to output test

[twoqu]

I am not saying its the actual problem because of course it would limit boost. I am just trying to eliminate the WGFV wiring as a problem. Sometimes these cars reward you by throwing another issue into the mix.
You may have just stumbled onto something else.
Perhaps the WGFV has detiorated and is not that quick to respond. However we need to do something to restore activation. As it has power it can only be the ecu disabling it.

[Monkeymagic]

I tried a new n75 no joy I agree the Ecu is clearly not sending the signal so ill double check the mfts

[newsh]

have you got a boost gauge on the car? If so what is peak boost that you're seeing?

[Monkeymagic]

No there is not a boost gauge so we don't know what it peaks at.
All I can say is that when we sort the boost cut it will be great as its very quick and responsive as I've said before its different to my 3b coupe

[Monkeymagic]

I have been reading into this Pin 'R' will disable to signal from the ECU if the the switch gives a zero Voltage reading.
This should only happen if the watertemp exceeds 119C however it has entered mt mind that the i noticed the wires are corroded. I wonder if the 'R' wire is corroded threrfore seeing zero volts and therefore disabling the WGFV via the ecu...??? Again purely guess work based on a little bit of knowledge

[newsh]

This is why we've been saying to try the car with the MFTS disconnected.

[Monkeymagic]

I know mate. I just don't understand why disconnecting It makes any ddifference to receiving no signal due to a corroded terminal

[Monkeymagic]

Anyone?

[Greg_S]

By disconnecting that signal cant be generated

[Monkeymagic]

But if the fault lies with corrosion On the plug then it would not generate the signal surely
its not like it's giving the overheat warning. When I get 5 mins Off Work i'll have a look again

[twoqu]

The official explanation is on P85 of the link that Mike provided in Post 35.
If the voltage at Pin 46 is greater than 2V, boost control is active. If its less than 2V it is not active.
However the MFTS as its name suggests contains switches for the overheat signals, I think that its likely that the overheat signal is in fact a switch to ground which some say is 0V!
So removing the connector means that this ground is disconnected. I don't think its possible for the connector to ground internally between the contacts.
Then there is the difference between the 4 pin and 3 pin MFTS. As the 12V feed to the 3pin was made redundant it would suggest that it was not used to generate a voltage for the overheat signals which supports the switch to ground theory.
Anyway for the purpose of seing whether the MFTS is stopping boost control activation we don't need to know exactly how it works. If you pull the connector off the MFTS and the WGFV works from the output test and does not work when reconnected, you have to point the finger at the MFTS even if it is new!

[twoqu]

Don't forget that there are 2 overheat signal. One is for the ecu. So its possible it that one that is malfunctioning.

[Human Joist]

Cheers for this guys. So if I understand correctly the circuit is not completed if the mfts is faulty OR the wiring to the mfts is faulty. So unplugging it negates both the wiring and the mfts. Will check it now then re post in 15 mins

[Human Joist]

Unplugged and driven. Felt a little different to drive but I have been driving other cars today. Got up to 110 in 6th without a boost cut. So I presume it's faulty wiring rather than a failed brand new genuine mfts ?