2001 B3000 or Ranger 3.0 Looking for Pin Out of the ECU or. wiring Diagram

[docmott]

I have no voltage to my engine coolent sensor Im not sure if its a wire problem or ECU? I think the pin no. is 38 but is that looking at the ECU or the Plug?

 

[Uncle Gump]

So I moved your post to the 3.0L forum... I also deleted your duplicated post.

ECT gets a 5 volt reference voltage and the signal is pulled low at the ECM. The 5 Volts reference is shared by other sensors on the engine. So if you have 5 volts at say the TPS... the ECM is fine. You most likely have an open in the 5 volt ref circuit. Also... there is no ground at the ECT.

I thought this post also had the schematic that the other post had... but it didn't. If I remember the 5 volt ref was on pin 40 and the signal return is on pin 38 maybe. If you repost the schematic we can double check those numbers.

 

[docmott]

Up date, at pin no, 38 I have 2.7 volts I thought it was 5v ?

 

[Curious Hound]

Up date, at pin no, 38 I have 2.7 volts I thought it was 5v ?

If that's the signal return, it could be less. The reference is 5 volts and the sender drops part of it. That 2.7volts is what the ecu interprets as "x degrees". So, depending on the temperature, you could get a return anywhere between 0 and 5 volts or some range within those values depending on how the circuit is designed inside the ecu.

 

[docmott]

Ok Thanks Eric, im getting somewhere , so I see the coolant sensor and others are all connected to a Gray/Red wire, is that a ground? what do I test it to? Volts or ohms?
Also after I replaced the heads my temp gauge isn't working? could I have pinched these wires somewhere along with the coolent sensor wires ?

 

[Uncle Gump]

Ok Thanks Eric, im getting somewhere , so I see the coolant sensor and others are all connected to a Gray/Red wire, is that a ground? what do I test it to? Volts or ohms?
Also after I replaced the heads my temp gauge isn't working? could I have pinched these wires somewhere along with the coolent sensor wires ?

That gray/red wire is the 5 volt reference. you test it with a voltmeter.... all sensor should have 5 volts on that circuit.

 

[docmott]

Thanks, Just checked it, got 2v ? I'll try and find the other sensors that use it and check them.
when I run a key on engine running test it says incomplete because of the ECT isn't working.
Other odd thing passenger side bank is running real rich compared to the driver side ? im thinking this could be caused some by the ECT, but doesnt make sense that its not both sides?
it was like this before I did the heads. im still wondering about the ECU?

 

[docmott]

OK todays test key on motor running at the PCM pin 91 gr/rd wire Volts 0.03 No sensors have any volts on the gy/rd wire. So PCM no good?
if I went from volt to ohms and direct short?

 

[docmott]

Part 1 fixed, all sensors are good and working, problem--- stuck open thermostat. motor never got out of short term fuel trim.

Now time to see what's going on using the iPad fuel trims, O2sensors, injectors, etc.

 

[Shadowridr1]

Part 1 fixed, all sensors are good and working, problem--- stuck open thermostat. motor never got out of short term fuel trim.

Now time to see what's going on using the iPad fuel trims, O2sensors, injectors, etc.

Got anywhere with this?

 

[docmott]

will now it runs great, fuel trim Long and short and looking good. O2 sensors upstream and down appear to be good. the open thermostat was the issue. It was replaced when I replaced the heads. also the temperature sender and the temperature sensor. with the thermostat open the motor wouldn't warm up, I thought it was the temperature sensor or wiring, it threw off all the fuel trims and O2 sensors because it was running rich. simple fix but took a while to figure it out.