teamsmith Posted June 26, 2015 Share Posted June 26, 2015 I'm trying to figure out how to tap into the HO sensor that is threaded into the thermostat housing on my HO motor using the renix wire. The renix wire is for only one post while the HO sensor that is threaded into the thermostat housing has two posts on it. Can I use the HO sensor or do I need to get something else to thread into the housing? Thanks! Tim Link to comment Share on other sites More sharing options...
Eagle Posted June 26, 2015 Share Posted June 26, 2015 Do you still have the Renix wiring and ECU, or did you replace the electrics with the HO engine? Assuming you still have the Renix wiring, the Renix temperature sender has a single wire that's hot, and it grounds through the body of the sender. The operating voltage is thus a nominal 12 volts. I believe the new style operates on a 5 volt constant input from the PCM, and then grounds back through the PCM. You could try just connecting one wire to the Renix hot wire and grounding the other to any bolt on the engine, but I don't know if the voltage difference will affect the readings. Link to comment Share on other sites More sharing options...
teamsmith Posted June 27, 2015 Author Share Posted June 27, 2015 thanks eagle. Yes, I'm still on renix wiring. I'll try fiddling with the two posts after I get my clutch issue solved. Link to comment Share on other sites More sharing options...
Crash Posted June 27, 2015 Share Posted June 27, 2015 Best thing to do in this case is go to your local parts store, and pick up a threaded "bushing" to adapt from the housing to a one wire renix sensor. I believe that the t-stat housing threads are 3/8 npt and the renix sender is 1/4 npt. Link to comment Share on other sites More sharing options...
HOrnbrod Posted June 27, 2015 Share Posted June 27, 2015 ^^ This. The HO temp sensor isn't going to work for you. Even though the output to the HO ECU is referenced to ground, the resistance value of the Renix vs. the HO sensor is not the same so you will get a false reading. Also the signal polarity output from the HO temp sensor will be opposite that of the Renix sensor just like the HO fuel gauge rheostat. Adapt the HO stat housing threads to the single wire Renix sensor and you will be fine. Link to comment Share on other sites More sharing options...
Jeep Driver Posted June 27, 2015 Share Posted June 27, 2015 Ahhhh..........what am I missing? Would not be easier to swap the housing and retain your original sensor? Link to comment Share on other sites More sharing options...
Jeep Driver Posted June 27, 2015 Share Posted June 27, 2015 OK, sorry. I guess there's no plug on the head? Link to comment Share on other sites More sharing options...
Siopposition Posted June 27, 2015 Share Posted June 27, 2015 He swapped in a HO motor. The HO temp sender is in the thermo housing, renix is at the back of the head. I'm assuming he doesn't have a hole back there any longer Link to comment Share on other sites More sharing options...
Siopposition Posted June 27, 2015 Share Posted June 27, 2015 You must have posted while I was typing..... Link to comment Share on other sites More sharing options...
HOrnbrod Posted June 27, 2015 Share Posted June 27, 2015 He swapped in a HO motor. The HO temp sender is in the thermo housing, renix is at the back of the head. I'm assuming he doesn't have a hole back there any longer The coolant temp sensor for the dash gauge (or idiot light) is in the back of the head for both Renix and HO. The HO stat housing temp sensor is for the ECU. Link to comment Share on other sites More sharing options...
Rockfrog Posted June 27, 2015 Share Posted June 27, 2015 The Guage sender hole was there until at least 95, the 7120 head HO's had a sensor arrangemet much like the Renix. Temp sensor in head and ECT for PCM located elsewhere. In 96 the 0630 head was used but I believe the early versions still retained the rear sensor hole (eliminated in later castings). Unless he used a 97 or newer motor the sender should be there for the Guage and the Renix ECT will fit right into the thermostat hole (if you remove the wires from the harness bundle there should be plenty of length to relocate it, in fact slightly too much if memory serves). Or, just plug it with a 3/8" NPT plug. Link to comment Share on other sites More sharing options...
teamsmith Posted June 27, 2015 Author Share Posted June 27, 2015 I should have clarified that I have a '98 to simplify the discussion. I have no provision for the sensor in the head so I'm stuck using the thermostat housing. I'll check out getting a threaded bushing to increase the size of the renix Sensor Link to comment Share on other sites More sharing options...
Rockfrog Posted June 27, 2015 Share Posted June 27, 2015 Yeah, easiest method ... Should only run you $1 or so for a fitting from home Depot or similar. Link to comment Share on other sites More sharing options...
cruiser54 Posted June 27, 2015 Share Posted June 27, 2015 Lengthen the wire to reach a Renix SENDER adapted to the hole in the HO thermostat housing. Link to comment Share on other sites More sharing options...
teamsmith Posted June 28, 2015 Author Share Posted June 28, 2015 Thanks guys. That will be my plan. Link to comment Share on other sites More sharing options...
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