My Seicento has started to run rich, I have checked the temp sender in the inlet manifold,which is working ok. The Lambda sensor heater checks out ok, but I have no batt voltage from the vehicle to power it.
Where does the power come from to energize the heater?
Would a faulty supply make it run rich? or is there two faults?
It's a 1999, 1.1lt sporting with sp injection and only 1 Lambda sensor.
It drives ok ish, but is lumpy at idle.
P.S I have changed the plugs (old ones very sooty) run with no air filter, disconnected the eng breather and checked for any obvious leaks.

Thanks for any help

Steve

has the engine warning light come on?
coolant temperature sensor ok? leak on the map sensor?

The warning light has not come on.
I have checked out coolant sensor with an ohm meter, and it seems ok
I will have a close look at the MAP sensor.
I found a 10 amp fuse, under the bonnet that had blown. The hand book calls it electronic injection sensor fuse, I have changed it and will check the plugs when I have done a few more miles.

Thanks for your help

Replacing the blown fuse seems to have fixed it, a bit easier than I thought it was going to be. Thanks for all your help.

Steve