Did u replace the SENDER or the sensor before. TWO differnt Parts. The sender only sends the information that you can read on the gauge. That is the easiest to get to. What you are describing happened exactly to me , but my Performance chip over volted my ECT Sensor and it wasnt my sensor but my chip, but same effects. What im saying is , If uve been replacing the Single Purple/Black Striped wire sender, you are going after the wrong location. To get to the actual ECT Sensor , Its Under the air conditioning bracket. That is the Correct TWO wire ECT Sensor that sends the data to the ECM. That sensor would have a effect on engine operation , not the single wire sensor!!!

 

Lot's of information coming in. I really appreciate it.

I replaced the SENSOR before, the one with two wires that's a bit nasty to get at. I'm going to try to find the sender and replace it to see if it has any effect.

I'm going to skip the tune up for now, as suggested, check the IAC and then move to the o2 sensor(s) if my problem hasn't gone.

Thanks again to all. Update tomorrow.

 

Alrighty I hope you the very best of luck , But if your in that area, would you do a quick test for me. Hook up a DC Volt meter and messure the voltage at the sensor.

Also , when you replaced the sensor the first time did you clear the check engine light? Maybe its still on for the ECT even tho its good now , and has a new code that you might need retrived.

 

Hello again!

I'm feeling like a bit of an idiot here, but I can't find the ECT SENDER anywhere. The SENSOR, which I replaced, is right where she's always been, behind the generator under the bracket.

I've got the right piece, with one wire. My shop manual doesn't list it. My Haynes manual doesn't list it.

Anyone out there in the middle of the day with a solution? It's killing me.

Thanks again.

 

I might be wrong, but I don't think the OBDII trucks have a SENDER like the one described. You have a 2 wire coolant temp SENSOR and that's it.

96 was a funky hybrid year for OBDII, rules are out the window on that year. After and before should be pretty standard.

I would disconnect both the + and - battery terminals and touch the wires together (both OFF battery of course) to reset the PCM. See if that helps.

 

Here's the story on this. I figured this out when I was studying intake manifolds. On older trucks (pre 1997), there were two coolant related senders/sensors, one for the PCM (the ECT sensor) and one for the temp gauge and warning light (a sending unit). The one to the left of the thermostat housing is for the sending unit, and the port just behind and to the right of the t-stat housing is for the ECT. In 1997, they started to switch to a single coolant temp sensor/sender. Not all of them had it though, some still had the 2 units. That's why some intake manifolds for '97 have two ports for sensors/sending units up by the t-stat housing and some only have one. This went on through 1998. By 1999, they completed the transition, and all should have just one single sensor/sending units. What year is your truck?

Anther way to tell is by how many wires are coming off the sending unit you can see. If I recall correctly, there should be either 3 or 4 wires on the single sensor/sender setups ('97 and newer), and only 2 wires on the ones that are separate sensor/sending unit ('97 and older).

 

Mine's a 98, 5.2l V8.

The tech at the dealer who was kind enough to talk to me on the phone verified that there are in fact two on my truck. The sensor that's visible has two wires, which jives with what Silver_Dodge is saying.

My issue now is I may not be able to get to it without pulling the A/C compressor, which I've never done. Haynes says to have a dealer discharge it. Any way around that?

 

Also, I reset the PCM and it threw the same code: P-0118.

Thank god the weather's nice. I'm making a beer run, to increase lubrication to my brain.

Thanks again, guys.

 

You don't need to discharge it. When I replaced my intake manifold with the modded one, I just unbolted the ac compressor and moved it out to the side, leaving all the lines attached to it. It moves enough to give you plenty of room. You might also need to remove the alternator and the accessory bracket. All easy to do, just time consuming. If you have to have all that stuff off to do the sensor/sending unit, it might be a good time to go ahead and replace your thermostat and the waterpump bypass hose, both good preventative maintenance steps, and easy to do if you have access to them.

 

Thanks again, Silver_Dodge. I'm off to get into it.

Updates to come.