3.9 efi lamda

hybridv8 · Post by **hybridv8** » Fri Apr 18, 2008 8:24 pm

hi all,
ive just fitted a 3.9 hot wire efi system to a rebuilt/modified 3.5 engine,
but have not fitted the lamda sensors to exhaust, as i have no lamda sensors fitted to my exhaust,ive also run the engine for about 250 mile,with no problem,my question is should they be fitted,and what could happen if not fitted,thanks..

kiwicar · Post by **kiwicar** » Sat Apr 19, 2008 7:09 am

you dont have to fit the Lambda sensor, but you have to tell the ecu by fitting a green (i think 470 ohm) tune resistor to the ECU, and reset it by taking away the power for 10 seconds, it will be in limp home mode until you do this and will be washing the bores free of oil.
Mike

hybridv8 · Post by **hybridv8** » Sat Apr 19, 2008 10:09 am

hi Mike,
thanks for reply,as im new to efi,im not sure what a tune resistor is or looks like,and where would i fit it,have anybody got a picture of one and where you fit it,also where would i buy one from,as i say im very new to this,many thanks..

hybridv8 · Post by **hybridv8** » Sat Apr 19, 2008 6:51 pm

hi all,
a friend as heard that not connecting to lambda sensors,may resault in rinning to rich or to lean,im now very worried,would changing to a green resistor,sort this out,thanks..

kiwicar · Post by **kiwicar** » Sat Apr 19, 2008 8:41 pm

Er yup that is what I was trying to say in the post above, without the lambda sensors and the wromg resistor it will be in limp home mode and in this mode it runs the mixture very very rich, washing the oil off the surface of the bores and it also kills the plugs.
The tune resistor is in a socket in the ECU, I'm afraid it is time for the haynes manual of Google time. unless someone else knows where in the ecu it is.
Mike