RUNNING a98 uk turbo replaced ecu with another S8 out of a Terzo all fittings are the same changed chip set and subaru imobilizer but fuel pump wont imobilize.Fuel pump replaced about 4k ago walboro 255.Any ideas?

 

do you mean pump wont go or wont turn off

 

why the ecu change?

 

had unichip and boost chip fitted was told that there was a problem with original ecu as it would not fuel over 3k rpm,maff would not return less than 5 volts,does that make sense?

 

wont power the fuel pump!

 

There are 3 main areas that spring to mind with regard to the 98 ecu..
the crank and cam sensors, the fuel pump relay pin position, and the immobiliser.

If it were the ecu immobiliser then it would start and then stall after a couple of seconds or so. . so for the moment this is not the problem.

The crank and cam sensor pin locations of the Jap and UK ecus are reversed to prevent you swapping the ecu's over and running the wrong ecu map..
But you are fitting a Trezo ecu which is UK into a UK so we can discount that.

So the only remaining ecu issue that springs to mind is the fuel pump relay pin.

The fuel pump relay is on the 26way connector called B137 and is pin 7 or 17.
Swapping it from it's current location to the other.. may sort it.. or as a temp measure you can earth it to run the pump but i wouldn't recommend leaving it earthed.

But all that aside.. the car obviously runs okay on the original ecu.. making 318bhp it cannot be that shabby.. are YOU sure the original ecu was faulty?

Simon

 

I had this problem about a year ago on my 94wrx. Try taking the bottom of the rear seat up. Underneath it should be the wiring for the pump with a block connector that is not up to the job. It likes to get hot melting the plastic inside and creating a dodgy connection. Cut this out of the wiring and with a bit of luck your prob will go away! Good Luck!