Hey everyone-

I am in the middle of a carb swap from tpi on my 89 iroc.

I am keeping the ecm in the car since it seems to control a lot more than just tpi stuff.

I am unclear how my fans will work in this swap. The fan switch in the rt side head controls when the secondary fan comes on true? does the cts control when the primary fan comes on?

If the above is correct, does this mean the ecm is controlling both of these functions?

At what temps should the fans be coming on in a carb set up?

yes the cts controlls when the fans turn on. and if you only swapped the tpi setup for carb on the same engine, then the operating temps should be the same.

All wrong. The passenger side head has a sensor in the back between the 7 and 8 cyl. that controls one fan. When AC is turned on, once a certain pressure builds up in the line, the second one comes on. All the CTS does is tell the ECM how cold the engine is at startup so it can determine whether or not to use the cold start injector or, if the car don't have one of those, to hold open the #1 injector a hair longer for cold starts.

My suggestion is to rip out the ECM and wire in a switch to the dash so you can turn the fans on or off. If you have an auto tranny, you'll also need to figure that out for the TCC lockup, which I don't know much about since my car is a 5 speed.

No, the CTS works in conjunction with your IAC counts. Fuel prime happens with or w/out it, and the fuel pump is triggered when a certain RPM is realized....

I use this and works great. You'll have to run a 180' t-stat.
http://www.summitracing.com/parts/DER-16738/

If not, this works good too. Just watch the temp gauge after the t-stat opens and set the fan to turn on at desired temp.
http://www.summitracing.com/parts/DER-16759/

Good luck.

I went with a Hayden fan switch..

thanks everyone.

have to wait till it comes in the mail from amazon..

What I am going to do with mine is wire it up so both fans come on when I turn on the car. This will I hope keep the operating temp much lower by having both fans running at the same time rather then just one. Plus it should save me money on a switch.

Good choice on the fan switch and I would keep the ecm in the car with everything else hooked up no point in messing with anything else. If you do need a way to lock up your torque converter for your overdrive there are a few kits offered to control your tcc solenoid with a switch. http://www.jegs.com/i/TCI/890/376601/10002/-1

Yes it will save you money on a fan switch, but in the long run it will cost you money on fan motors since they arn't designed to be run all the time, it will cut their lives short. It will also take your car longer to reach operation temp, especially in the winter. That being said that is how I set the fans up on my last carb swap, it worked just fine, I did however replace the fan motor (single fan setup) a couple times.

Do you think it would be a better idea to run the fans on a toggle switch then? I just dont want to take the risk of accidently leaving them on if I was in a hurry to get out of my car. Maybe I could wire them up so they would only have power when the car was on. What do you think?

I don't reccomend it. but what i did was Ground the relay switch so when i turn the car on to accel. it turns the fan on continuous circuit until i shut the car off. Only had to replace the fan once. Because it was orginal and the bearings went out on the other one. But doing this the relay switch will fry before anything else. I had to change 2 of those in the lifetime. I did toggle switches on cars and I forgot to turn them off and few hrs later. DEAD battery. So i decided to do that. Not ethical by all means. but it works and been working for 2 years.

As that is noted I will be setting one up soon with toggle switch that when no power the toggle switch won't work on or off. and once i turn the Key over it will put power to the toggle switch so if i forgot to leave it on it would shut off anyways after i turn the key off.

I would think there would be an aftermarket switch of some kind that you could wire up, that would screw into a coolant sensor hole or something that could kick the fans on and off. Does anyone know of one? And also about the TCC lockout switch from jegs that was posted, how would you install that? I really need to get one.

saving info