[Mk2] [Turbo] Code 34 with FCD fitted - any help??

[JasonB]

Since the improvements to the weather I've had a few cases where my 1993 turbo with ct20b and TBD MBC (at 15psi) and FCD is hitting boost cut and throwing up a code 34 error message.

Now I thought the FCD was able to elliminate boost cut totally. The potentiometer screw on mine is able to turn and turn with no stop or maximum on or off position.
It's getting to be a right pain as it cuts around 12psi the first time then gradually comes down so it stops play at around 3-5psi.

The MBC screw is backed out most of the way and not sure what else to look at. The FCD connections are all fine.
Any ideas on a possible cause??

JB

[jimGTS]

fcd is designed to raise, not completely illiminate fuel cut.

if you want to completely remove fuel cut, then you could cut and plug up the pipe going to the map sensor. tho not entirely recommended as a high boost spike could be enough to damage the turbo/engine.

[bobhatton]

fcd is designed to raise, not completely illiminate fuel cut.

if you want to completely remove fuel cut, then you could cut and plug up the pipe going to the map sensor. tho not entirely recommended as a high boost spike could be enough to damage the turbo/engine.

I think that can only be done on Rev1&2 cars but not on Rev 3 as the map sensor is used for fueling adjustment.

Bob

[jimGTS]

fcd is designed to raise, not completely illiminate fuel cut.

if you want to completely remove fuel cut, then you could cut and plug up the pipe going to the map sensor. tho not entirely recommended as a high boost spike could be enough to damage the turbo/engine.

I think that can only be done on Rev1&2 cars but not on Rev 3 as the map sensor is used for fueling adjustment.

Bob

hense why i suggested it, as he has a rev2...


but yeh, certainly not recommended on a rev3+

[JasonB]

Cheers guys,
the only reason I was trying to elliminate bost cut was just to prove that the fcd is working.
I suppose I was expecting the potentiometer in it to have a maximum clockwise position whereby no cut would be happening.

I'm a bit miffed that the car is hitting boost cut so I just need to confirm why. I'm only going for 15-16psi boost and at the moment it's cutting at around 12psi the first time then less each time it thinks it may happen.

Coming home from work this week it was cutting at around 3psi and I had to nurse it to get up the steep hill onto my estate.

Should the fcd screw just keep turning? Surely it only has a set resistance to a complete turn??

JB