C12nz Overfueling

[HASS]

I have a C12NZ SPI set up in the back of my sons Autograss Junior Special, it seems to be massivly overfueling while we try to start it, the only way we can get it to start is to crimp the fuel inlet pipe between the pump and the SPI unit till it fires then release it !!

Any ideas much appreciated

[John]

coolant temp sensor is goosed.

[GDN16v]

Lambda sensor?

[HASS]

I have swapped the coolant temp sensor for one off a spare engine and it makes no difference, but obviously I cannot guarantee that one is any good either, perhaps i will order up a new one and a lambda sensor.

[mowgli]

what pump are you using for the injection??? the spi is a lowish pressure one. does it need a separate regulator?

[HASS]

I am using the origional pump that would have sat in the tank, and the fuel pressure is spot on from the pump.

[HASS]

Just put a brand new coolent temp switch in and that hasnt cured it !!

[HASS]

Just changed the Lambda sensor and the car is still overfuelling badly and flooding the engine whilst trying to start !!......any other ideas ???

[HASS]

We have now changed the CTS, MAP, LAMBDA, FUEL PRESSURE REGULATOR, INJECTOR and still we cannot stop it overfuelling. we have just re wired the diagnostic socket (which we had cut out of the loom to save weight !!!!!!!!) and having plugged in the computer it seems that the ECU is making the injector stay open for a much longer duration than it should (11 seconds) and the ECU has altered the timing by nearly 90 deg to try and counteract the overfuelling.

seems like the ECU has a software fault but we have just swapped the ECU and this has made no difference at all !!

Some body must have some ideas !!!