Fuel Issue

[USMC302]

Originally Posted by 5150coupe

Update with ect: maybe I’m using the wrong terminology, but I believe it is the ect that gives a reading to the computer that in turn tells the injectors to run rich when the motor is cold and lean when the motor is hot, but maybe it is called something else.

The 02 sensors are going to detect the rich or lean condition and tell the computer to give or take fuel away. The ECU constantly tries to achieve a 14.7 a/f ratio. Might try cleaning the MAF as well, it monitors how much air is coming into the engine ad in return tell the computer how much fuel to add to achieve the desired a/f ratio...The best way to see if your running lean is to install a wideband, from there we can really see what's going on.

Originally Posted by 5150coupe

Anyway, I installed the sensor that was missing directly into the port right above the thermostat in the manifold and the car seems to run a lot better. The ect is important since it tells the computer when the engine is cold and then warm.So if the ect isn’t connected the car can run to lean in a certain period of time and rpm range after starting the car and before it fully warms up.

This really doesn't make sense to me, I'm no expert either but I've run my autometer guage wire off of the ECT for a few years now with NO other wiring going to the ECT and never had any problems. Which means the ECU doesn't even see that I have it plugged in. The sensor your plugging into above the thermostat is going to be for your knowledge only, I don't beleive it sends any signal to the ECU. I believe there is another place or sensor that the ECU gets the temp signal from. I can unplug my Autometer guage from the ECT sensor and my PMS still reads the engine temp from somewhere else...

You said your running a 76mm C&L, are you running stock 19lb injectors? Was the MAF calibrated for the 19lbers or did this come on the swapped engine? What year is the engine out of?