My Scoob's got a fueling problem, it seems to hit fuel cut in 2nd at the top end of the rev range, the rev counter just drops to zero. In 3rd it comes on earlier. In 5th on the motorway at say 70 - 80 it will det backfire at 0.7 bar, at a ton it does this at 0.3 bar. I have a chipped ecu in but Im rulling out any sort of boost problem, it does it with the Z4 aswel. Ive tested the actuator which is fine and cleaned out the boost solenoid. The coil packs are good but the centre electrode on the plugs are white, Ive done an ecu reset and no fault codes are coming up. Im thinking its the fpr or fuel pump, I need to test the fuel pressure and get a wide band lambda on it but cant do this for a few days. Also if I pipe the compressor outlet directly to the actuator it boosts to 0.5 bar and will det in 5th. Has anybody got any ideas?

 

a batch of poor quality fuel maybe?

 

I always use V Power or Tesco 99 when I can find it, I also put in an octane booster on the last fill up which made no difference. I picked up a Walbro and fpr today, the walbro is in but I havnt tried it yet so heres hoping.

 

Well the Walbro did improve it slightly but the fault is still there and the fpr made no difference. There is no splits in any hoses.

 

I dont have a kph to mph convertor, could this be why I am getting problems? At the moment I am using a chipped uk type ecu, I am also using the MAF which came with this ecu. I think a swap to the original ecu and MAF would be the way to go. What do you think?

 

wont the UK ECU be setup for the TD04 turbo? WRX has a bigger TD05...

 

No, WRX wagons are the only ones that have TD04 (Pre96). Everything else is TD05

check the restrictor is still in the return hose on the boost control solenoid.
this is the hose from the v.bottom that comes out of the base of the solenoid. it should have a small brass restrictor inserted in it with a 2mm hole in it.

if this is missing or been thrown away after fitting an induction kit, then you need to put it back.

with this missing a Z4 ECU with a decat may still fuel-cut.

 

Had a look and the restrictor is still in there.

 

The car is fixed I put back in the original ecu and its sweet as. So it must be something to do with the dash sending a kph signal to the ecu, Ive ordered a kph to mph convertor which should be here tomorrow. One thing I dont understand though, shouldnt the Z4 be capable of handling a kph signal?