Ive ran into some cooling problems after installing new heads(Aluminum 113's) and I think its because my fan isn't not turning on. I was setting the timing, and the fan never turned on. The temp was at 240, and it didn't turn on.

My brother knew that when you check for codes that the fan should turn on so he did that, and the fan turned on. So I know that the fan itself works, but why wont it turn on when it gets that hot? Could it be a relay or something?

 

Did you install the fan switch when you swapped heads? also check the fan switch connector, it gets brittle over time and breaks.

 

I bought a fan switch but I have an 86 and its controlled by the ECM via the CTS in the intake manifold.

 

so its a dual fan setup? if so the primary fan is run by the switch and the secondary is controlled by the ECM.

 

No its a single fan.

 

do you have a scan tool? check and see what temperture the ECM is seeing. also check the CTS connector for corrosion.

 

I don't have a scan tool, maybe I can ask around. The CTS connector is the one thats like the fuel injector plugs right?

 

no, thats the cold start injector switch, the CTS is beside it smaller connector with yellow and black wires.

 

I just saw your post. Thats a cold start injector switch, whys it in the front of the intake. Anyway, its the one next to it so I'll check the connection once it gets nicer outside. Also could it be that the CTS itself be bad?
Now when I had the intake off, I tried to get all the sensors and what not off the manifold, but that one was the only one that wouldn't budge. So if it is bad I'm going to have a heck of a time trying to get it out.

 

yes it could be a bad CTS, My 87 GTA had a simalar problem and it was the CTS connector that had corrosion on it and was no longer making connection even though it was still plugged in.

 

Really need a scan tool. If your fans or fan are coming on in diagnostic mode the relay is working and you have good grounds. I'm not that familiar with single fan cars. If I'm wrong someone speak up. Engines other than a 350 TPI could have single fans and AC. If you have AC does it turn on this fan?
GWW

I found this link it has what I think is the wiring schematic for your car. From it, it appears your single fan should turn on if you switch on your AC. It also shows the auxillary fan but you don't have that.
http://www.autozone.com/az/cds/en_us...rInfoPages.htm

 

Well I was able to take some time to see if the fan would come on while the AC's on, and the fan came on. So I'm guessing its the CTS or the connector.

Now if I want to change the temp in which the fan turns on I have to reprogram a chip for it?

 

You will have to get your connector fixed because the computer needs the sensor.
Summit racing makes fan switches to turn your fan on earlier.
GWW

 

I checked the connector today and this is what it looks like. I'll be buying a new one today from EFIConnection.com And look into buying a fan switch.

I found this: https://www.thirdgen.org/cool Should give me a good starting place.

 

What did i tell ya, Check the connector. LOL I am glad you found the problem

 

Yup, you da man

Thanks

 

Well I got the connector a couple days ago, and put it on today. The car got up to about 230 maybe a little less, and the fan still didn't come on, maybe it needs to get hotter? Since it didn't come on I turned it on via the AC, and the temp drop to 220 pretty fast, when it got down to 220 I just turned it off.

OH and how long should it take for my car to get to 200-220?

 

I was having a similar problem myself. My fan wouldn't come on at all. My coolant temp sensor was out. It was only like 12 bucks to replace. After replacing it my fan would come on at about 235 with the car sitting.

 

I got the CTS out, now do I put on thread sealant on the threads, or not? Only reason I ask is because I was wondering if it needs to be grounded via the threads.

 

The CTS has a two-wire connection and one of the is ground. So you don't need to worry about grounding it through the threads, you can put as much sealant on the threads as you need.

Have you tested the CTS yet? You can check its resistance with an ohmmeter. The reference table below will give you the resistance values for certain temperatures.

Hope this helps.
Lou

 

Rich92, you always have the option of hooking up a manual switch to turn your fan on. I hooked up my dual fans to manual switches and an LED for each relay so I know when the fan is on. And, in case I forget to turn on my switch, the factory switches still work and will turn on the fan.

 

Got the sensor in yesterday and let the sealant set over night. And the fan still doesn't turn on . I have no clue whats wrong. Ive replaced the CTS, and its pigtail. And all the fuse's are good. Any other ideas? I really need to get the car on the road again.

I plan on get a manual fan switch or something, but first I want to figure out why it isn't working. I didn't test the old CTS, I just bought a new one.

 

Are you sure your temp gauge is reading correctly? Did you do a resistance test on the new sensor? Since it is a 2 wire sensor, you can still test it while installed in the engine. At the very least if it tests correctly, it may give you a more accurate reading than your gauge. If your gauge shows 220 degrees, but the sensor ohms out to 180 degrees, then you can atleast have a clue which way to go. It could be that your fan isn't coming on because the temp isn't high enough. It could also be that you got a bad sensor, but you won't know for sure until you ohm it out.

 

OK my bro and I did a resistance test and heres what we came up with up. Now when it comes to electrical things I don't know anything, so heres what I wrote down.

There were four settings for the Ohms test: 20M, 200K, 2K, and 200. I didn't use 200. We tested where we spliced the wires together with a butt connector.

Setting/ Reading/ Temp Gauge

2K/ 803/ 160
2K/ 793/ 200


200K/ 36.2/ 220


20M/ 3.64/ 215

What setting should I put it on to test the resistances.

 

So did I do it right

 

As I mentioned in my PM, these resistance numbers don't make sense. I guess it's due to your statement "We tested where we spliced the wires together with a butt connector" which would indicate that you measured the resistance with the connector on the sensor, meaning in a circuit.

For ALL who want to measure resistence of an element: the element needs to be disconnected/removed from the circuit in order to measure its correct resistence. For example, a sensor connector needs to be unplugged or a part needs to be unsoldered from the board.

Good luck at the shop, hope they don't charge you through the nose for finding your problem.

Lou

 

Just got back from the shop. My gauge read 255-260, and he showed me his scan tool, it read 225, and my fan was on . The fan turned off at 213, then back on at 227 according to the scan tool. So either my gauge is bad or the temp. switch in the head is bad. Oh and they only charged me 20 for the test, very nice people. Now its time to learn how to fix the gauge if the temp switch isn't bad.

Thanks everyone for all your help.

 

Well I found a thread that will help me out in testing my gauge, posted by BigBabyLou: