SBpunk Posted May 3, 2017 Share Posted May 3, 2017 Ok so the problems continue. Little info/history. 1992 4.0 rebuilt motor 600 miles ago (still has break in oil) new water pump, 190 thermostat, thermostat housing, radiator, lower hose, coolant, ZJ fan clutch and stock electric fan (doesn't kick on until the line right before the red). Prior to the rebuild she would stay steady at 190. Now I'm lucky to stay around 215 but never gets above 230 now (after I swapped back to a 13lb radiator cap). I'm having the system pressure tested but was hoping to get some insight from you guys. Its been cold around here and when summer actually hits I don't want this thing spiking out of control. Link to comment Share on other sites More sharing options...
HOrnbrod Posted May 3, 2017 Share Posted May 3, 2017 My stroker ran at those same temps when new for the first 1000 miles or so. As far as the aux fan kicking on at ~230, that's normal. An easy fix (work around) is to wire in a dash switch to kick the aux fan on when you want to and not rely on the temp sensor on the thermostat housing. It applies a ground to ECU pin 31 turning on the aux fan like when stuck in traffic or going up a long grad in mid-summer. It doesn't interfere with the normal aux fan turn on/off settings either. After awhile when your engine is completely broken in and running cooler you probably won't need to use it except in extreme cases. Wiring diagram for the HO's: Link to comment Share on other sites More sharing options...
SBpunk Posted May 4, 2017 Author Share Posted May 4, 2017 I appreciate it. Was planning on running a switch anyway but looks like it was bumped up. Got it back and everything checks out except for the electric fan. The fan motor itself works but it's not coming on at the proper temperatures. It won't kick on with the A/C or defrost anymore. They swapped out relays a few times to ensure it wasn't that but I'm being told the PCM itself might be causing the issue. For now I'm just going to use a toggle switch and swap out the computer later. Another thing is that the temperature gauge on the dash isn't reading the same as the IR thermometer at the coolant housing. Hoping to find a replacement and seeing better numbers will make me less concerned and I can start focusing on my idle problem again. Link to comment Share on other sites More sharing options...
Eagle Posted May 4, 2017 Share Posted May 4, 2017 The dash gauge never reads the same as an actual thermometer aimed at the engine. Link to comment Share on other sites More sharing options...
SBpunk Posted May 9, 2017 Author Share Posted May 9, 2017 Ok gotta bump this its driving me crazy. Electric fan won't kick on by itself until its just under red. I'm talking close enough were if you move your head a little left its over heating. Anyway I've swapped out the ECU, thermostat, thermostat housing, temp sender, relays and even put in a new fan. Aside from the wiring harness itself any ideas what I need to be looking at? I have to do some research on how to test the signal the temp sensor is sending out. The fan is working since I have it on a switch now its just not getting the correct signal until its too late. Link to comment Share on other sites More sharing options...
Minuit Posted May 10, 2017 Share Posted May 10, 2017 Have you verified that the gauge is correct? Very often especially with aftermarket senders they read high. Link to comment Share on other sites More sharing options...
SBpunk Posted May 10, 2017 Author Share Posted May 10, 2017 Have you verified that the gauge is correct? Very often especially with aftermarket senders they read high. I have a new gauge in route. I used an IR to check the thermostat housing but like Eagle said it wasn't off enough to make any kind of decision. Was going to use a mechanical gauge but I found someone willing to sell me a working one for cheap. Also ended up getting a new CSF radiator. I'm pretty sure the guy that rebuilt my motor just threw in a cheap one since the temps at the radiator were pretty high. As far as the fan goes if it doesn't help I'll just leave it on with the switch during the summer and call it a day. Tired of chasing down little things every other day with this thing lol Link to comment Share on other sites More sharing options...
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