Originally Posted By: merconvvv
Originally Posted By: Colt45ws
afaik the sender is just one wire that goes from the engine to the cluster with no splices. The ecu doesn't know or care about the state of OP sensor.
If you wanna hear something really lame, in the Mercury Marauder the cluster does not have a OP or volt gauge, instead there are two Auto Meter gauges below the climate controls. Both are fake. Ford had Auto Meter brand them some dummy gauges.
The OP gauge works just like a gauge discussed here. It sits in the middle as long as the pressure switch on the engine is good. The volt meter also just sits at the midpoint as long as the engine is running. Unless there is a problem with the alternator then the pcm shuts it off and it goes to the bottom of the scale.
If thats the case then i dont see how the fuel is cut off.
Now lets suppose the oil sender fails. Will it throw a code? Does not sound like it throws a code. So it does not sound like the engine is killed or limp mode.
On some cars if its a single wire then the ecm to cut the fuel pump if the pressure signal s lost, it is sometimes connected to the inertia switch circuit on others they use a multi wire sending unit. Others if the oil light came on it just keeps going and nothing gets cut off.
It is vehicle specific which type if any is used, some will throw a CEL others wont, the more modern the car the better the chance it will, new cars are getting smarter every year.
Some cars use 2 pressure sending units one for the gauge and the other for the ECM only like some temp gauges.
The first car I can remember seeing an oil pressure circuit fuel cutoff was a 69 Riviera 430 C.I. GM used a 3 wire on some (the GS model IIRC) of them with an in tank low pressure electric pump so these kinds of systems have been around awhile. The GM 6.0 uses a 3 wire which cuts the pump in case of pressure loss.
The easiest way to find out is to pull the pressure switch wire and start the engine if it starts and runs for more than a few seconds its not protected.