Swapped an 88 V6 into an 87GT. Utilized the 87 harness (88 was mated to a 5 spd, 87 to an auto). Started the car and the temp gauge pegged at 100 degrees and the radiator fan never came on. So I proceeded to do the following in an effort to troubleshoot the issues....
Replaced the coolant temp sensor---- Gauge no longer pegs on 100 degrees (problem solved, I believe). Turned on the A/C----- Fan runs. Grounded wire to fan switch----- Fan runs (fan, relay and wiring good, I believe). Replaced fan switch (Rodney's low temp)---- Fan still does not come on (???????).
Current status---- Start the car and run for about five minutes or so. The temp gauge slowly climbs into the red (I shut it down before it does). Fan never comes on. Coolant hoses at the motor and radiator are hot so I believe I have flow. What am I overlooking??? Would air in the system cause the fan not to come on? Is there something electrical I'm missing (temp sensor for the ECM)? Any assistance in troubleshooting this issue would be greatly appreciated.
Based on what you're saying, I would not trust what you're seeing on the gauge. If touching the fan switch lead to ground turns on the fan, that whole system is working fine. Do you have Tuner RT that you can use to read the ECM sensor, or an IR thermometer you can use to get a sense of actual engine temp?
Sounds like my fan switch is faulty. They are mass produced and they spot check a certain percentage when they make a batch. I see a handful every year that are faulty. Send me an email and I'll send you a replacement.
------------------ Rodney Dickman
Fiero Parts And Acc's Web Page: All new web page!:www.rodneydickman.com Rodney Dickman's Fiero accessories 7604 Treeview Drive Caledonia, WI 53108 Phone/Fax (262) 835-9575
Based on what you're saying, I would not trust what you're seeing on the gauge. If touching the fan switch lead to ground turns on the fan, that whole system is working fine. Do you have Tuner RT that you can use to read the ECM sensor, or an IR thermometer you can use to get a sense of actual engine temp?
I don't think the gauge is reading correct either. Seems to be heating up rather quickly. I did swap the gauge with a spare I had laying around and got the same results. Guess I am gonna have to pick up some sort of scanner software so I can see exactly whats going on. Suppose I'll pick up an ALDL cable from Phonedawgz and download Tuner RT.
Sounds like my fan switch is faulty. They are mass produced and they spot check a certain percentage when they make a batch. I see a handful every year that are faulty. Send me an email and I'll send you a replacement.
Thanks for the offer Rodney. It may be, but I would like to put a scanner on the car to verify the true operating temperature to determine if the switch is actually faulty. I don't want you to have to send me a new switch if nothing is wrong with this one. Thanks for the offer though and I'll let you know how things work out.
You can test the fan switch reasonably well by sticking the end in a pot of boiling water and testing for continuity between the terminal and the body.
You can do a plenty-good test of the coolant temp sensor with an ohmmeter:
Verify with the ohmmeter that the coolant temp sensor agrees with your gauge.
IR thermometers are cheap at Harbor Freight, and you can get a good idea of what of the engine temp is, and what the fan switch thinks. Plus, IRTs are fun and useful to have around.
Run the car when the temp starts to climb turn on the AC which will force the fan on if the temp does not come down you have a blockage somewhere. Check for air in system or bent or kinked hose somewhere you may have flow but not volume. Worst case would be a bad water pump.
You have an air pocket in the area of the gage sender, causing the temp to spike quickly. The fan switch is located above the water pump, the coolant isn't hot enough to trigger the fan. Remove t-stat, run, fill, repeat until air pocket is out of engine.
Received my ALDL cable from Phonedawgz today. Thanks for the quick shipment. Downloaded TunerPro RT and ran everything up. Rodney your fan switch is working as advertised. The fan came on at 190 degrees and kicked off at 185 degrees. The gauge reading is still inaccurate though. I think I have an air pocket in the system as stated above since I have swapped out the gauge and its climbing in the same fashion on both gauges. I'll have to burp it again when I get the front suspension back together. I may even take it to get flushed on a pressurized coolant machine. I also noticed my tach was off quite a bit as well. TurnerPro was reading an engine speed of 1025 +/- rpms but the gauge was reading around 1400 rpm. I am including a couple screenshots from TunerPro below. Most of what is displayed is Greek to me to be honest. If anyone could take a look at the info and tell me if something is standing out to them it would be greatly appreciated. Thanks again to everyone who has replied so far. I am learning allot right now.
[This message has been edited by WickedFieroGTP (edited 06-01-2015).]
