Strange overboost conditions?

[Benparker29]

Bit of background, bought a mk2 turbo about a month ago, all good, few issues with the recirculating system but seemed to be sorted after some fiddling, installed a Greddy electronic boost controller and plugged the line coming from the actuator to the tvsv and also unplugged the blue connector from under the car, I also installed a fuel cut defender to raise the fuel cut, however, the car cuts around 8psi and it’s level of cut changes depending on what gear I’m in, in 3rd it’s around 7psi, 8 in 4th and 9in 5th, this was with the fuel cut defender installed, I thought it may have been some wiring fault between the speed delimiter and the fuel cut defender, however, I removed the fuel cut defender and removed the vacuum line from the map sensor to prevent the stock fuel cut and the car worked perfectly, boosted well past 10psi and the car was fine, now all of a sudden it’s done the same thing as without the fuel cut defender and goes into it’s overboost mode and when it goes in this state it will fuel cut on any level of boost, after switching the Car on and off it allows boost again, I’m stumped as to what it could be, is the ecu cutting boost?

[GazRev1Tubby]

Sounds like you didn't wire the fcd correctly. What make is it, and what setting is it on?

[Benparker29]

That’s the thing, i have now removed the fcd and the car still fuel cuts, without a map signal because the vacuum line is off the map sensor or a fcd interfering how is the car boost cutting?

[jimi]

Knock sensor perhaps?

[MR2DI4]

Fuel cut is supposed to reset by turning off the ignition but perhaps disconnect the battery for a couple of minutes or pull the EFI fuse for a couple of minutes.

You must have a yellow engine check light coming on ?

[GazRev1Tubby]

You need to check for error codes. Jimi could well be correct and the knock sensor could have blown.
A duff knock sensor will generate code 52

[MR2DI4]

Also probably want to just check the static engine timing is correct.