2.3L ('83-'97) ECT temperature sensor testing? O2 sensor bad?

[Chapap]

I have many posts out there about my truck, but this seems to be the last problem. Every electrical component and sensor is new. (Ignition, fuel, air, exhaust). I just put a ground cable from block to frame, batt to frame, and batt to existing starter cable. The old one was terrible.

I run perfectly when cold but get rich when hot. Have memory code 173 O2 Indicating Rich. Is there a way to test the temp sensor to make sure it’s communicating with whatever is supposed to communicate with?

My 4 month old O2 sensor is suspect as I was running incredibly rich till I changed the ECU. It may be improving as I drive and am clearing out the O2 sensor, but that could just be bias.

 

[RonD]

ECT sensor would set a code after 8 minutes or so of run time if it wasn't reporting a temp higher than 150degF
But yes you can test it
Use a sewing pin to pierce the green wire on ECT, that goes back to ECU, ground meter and test voltage key on, engine cold
Should be about 2.8 to 3volts, 70degF, whatever outside temp is

Temp/voltage chart seen here: https://www.explorerforum.com/forum...rature-sensor-ect-resistance-chart.24365/full

As it warms up voltage should drop on the green wire, under 1v after 5 to 8minutes, 160degF

ECU usually comes out of choke mode once ECT reports above 140degF

If you see a red/white wire its the wrong temp detector, lol

 

[Chapap]

ECT sensor would set a code after 8 minutes or so of run time if it wasn't reporting a temp higher than 150degF
But yes you can test it
Use a sewing pin to pierce the green wire on ECT, that goes back to ECU, ground meter and test voltage key on, engine cold
Should be about 2.8 to 3volts, 70degF, whatever outside temp is

Temp/voltage chart seen here: https://www.explorerforum.com/forum...rature-sensor-ect-resistance-chart.24365/full

As it warms up voltage should drop on the green wire, under 1v after 5 to 8minutes, 160degF

ECU usually comes out of choke mode once ECT reports above 140degF

If you see a red/white wire its the wrong temp detector, lol

Awesome thanks. I guess if there is voltage, then communication is happening. I haven’t gotten any Ect code. I’m just baffled at this point. Hopefully it’s bad O2 sensor if this tests good.

 

[RonD]

O2 sensors last 12 year or 100k miles which ever comes first, they are the only sensor that actually wears out at a specific point
They use a chemical to detect oxygen in the exhaust and it just gets used up

 

[Chapap]

Ect tested good. I’m now thinking new injectors are letting thru too much fuel. Started a new thread.

2.3L ('83-'97) - Fuel injector- right and wrong options? Flow rates?

I changed everything and I’m still getting 173 O2 System Indicates Rich. Before changing ECU I got 179 At Lean Adaptive Limit During Part Throttle, so I guess that’s an improvement. I have no fuel in regulator vac hose (new) and was hoping the new O2 sensor was bad since it was running in such a...

www.therangerstation.com

 

[RonD]

1994 should have fuel pressure of 35psi, running, if higher than 50psi you will get Rich Codes

2.3l Lima should use 14lb/hr injectors, if you go larger you just get Rich Codes not more power

 

[Chapap]

1994 should have fuel pressure of 35psi, running, if higher than 50psi you will get Rich Codes

2.3l Lima should use 14lb/hr injectors, if you go larger you just get Rich Codes not more power

Shop tested pressure at between 30 and 40. I think it was between 33 and 38. I have no clue what my injectors lb/hr is. I cant find any specs on them. That’s the current question.