Can you adjust when your fans turn on and the speed with the PFC/commander? or when you run the PFC it already makes the fans turn on sooner

 

You need a DATALOGIT to adjust the fans

 

Also when you install a PFC straight out of the box it already turns the fans sooner than the stock ecu

 

my car seems to get warmer with my pfc installed, particularly in traffic. when it hits 104c it has a wandering idle 1k to 2k up and down, up and down.

however it is posible that my car got this hot with the stock ecu and i never would have known because it doesnt change the cars characteristics. is this normal? or is 104 just way to hot??? im going to see if i need to burp my radiator system because it seems that it only gets to 104 on one side of the t stat.

any help would be great! thanks

 

If I'm not mistaken, the base PFC map flips the fans to high-speed at 105c.

 

yep, fan2 doesn't come on until 105C which is way too high, just got my datalogit in

 

i understand that fan2 kicks on at 105...but how come at 104 my idle bounces? is there any way that i can disable this? i now know that i need a datalogit to change the temp for the fans so i guess i will just do the fan switch mod untill i do have a datalogit. plus it will be a useful feature at the track. also what is too hot for an fd? im sure its been covered but i cant find it.thanks

 

hey how can i datalog this thing? i got the power fc when i bough the car. So i dont have this program to datalog, how do i get my hands on it?

 

For the newbs: you can do the fan mod switch conversion which allows you to increase the fan speed by 1. Which means if the fans are not on yet, they will go to speed 1.

On the back of the ECU is a black box and an unused single black spade connector. Grounding it turns the fans on (it is the same as when the thermo switch grounds out). This mod has been around since about 1994 when Mazda did the cooling system recall.


Do a search.

 

...but how come at 104 my idle bounces?

 

So here is a more ridiculous question. (and i have done a search for the fan swith mod and i cannot come up with instructions on exactly how to do it.) So the way i understand to correctly do the mod is to hook a wire to the unused black spade to a switch, then the other connector on the switch just gound it to the car somewhere?? is this right??


and on your idle bouncing, i am not sure why exactly it does it but my idle bounces like that at all times as long as the sensor on the back of the intake manifold (for emissions purposes only) is plugged in. I just unplugged the sensor and the idle runs smoothly at ~900rpm with NO bouncing. From my understanding some FD's bounce and some dont with the FC, there hasnt been any real explaination why....

 

Bouncing idle is usually an ISC/O2 feedback problem, caused by too much or too little air flow unless the O2 sensor is bad. Usually corrected by manually adjusting idle air flow quantity.

The fan mod is so old that any car that does not have it was previously owned by a dork! http://www.fd3s.net/fan_mod.html

 

Thanks for the link on the fan mod. The guy that owned the car before me did some stupid things and did NOT do other things that should have been done (i.e. fan mod). I am new to the FD but I am trying to learn as quickly as i can but some of the learning has been slowed down due to moving 800+ miles and starting a new job....

On the idle, I tried all the O2 suggestions above a few months ago (with the exception of replacing the stock O2 sensor). Like I said, mine corrected with eliminating the final part of the stock emissions junk that was still on the car.

 

My car had the same problem with the Power FC and at that exact temperature. My guess is that you didn't severe four of the wires that connect from the harness to the Power FC; alternatively, you can also plug the four plugs directly off the PFC--this is a permanent thing and you have to be sure you want to do it.

I didn't even know about it until Dhahlen was using his Datalogit on my PFC. It should be in the archives, but I can't find it because the search function sucks. Maybe some more seasoned Power FC users could offer some insight on this.

What I do know is that the problem went away after the four pins were removed. Sorry I can't be more help.

 

I understand how the datalogit controls the temperature at which the fans turn on. What controls the 3 fan speeds, and more importantly, when you lower the "on" temperature does it change the temperature and/or conditions at which the fans hit medium and high speed? Thanks.

 

it seems i have same problem,

I've 93' fd, and change my ecu for 95' japanese ecu

Now my idle fluctuate when fan run at hig speed.

I know there is a water temperature sensor recall in 94', perhaps mazda has change 105C to 104 C.

It's why the car fluctuate idle to cool down the car, i think

I' m going to buy new water temperature sensor? and see if it solve my probs.

What are you thinking about this?

 

When I owned the car, it did not need the fan mod.