rotorhvn99

Howdy all,

Just found a pretty serious problem with my 93 R1. My fans are only coming on when I run my A/C.

I parked the car after a drive to shoot some hoop after work & noticed that I overflowed a little bit of coolant. Not a signifigant amount, but coolant none the less. So I drove home, parked the car, turned off the ignition, then turned it to the accessory position. Typically, this would cause my fans to come on within 30-60 seconds. Today though, they didn't come on at all.

So I started the car back up & turned the A/C up to high. Low & behold, the fans both come on high. So now at least I know it's not the fans.

I'm guessing that I've got a sensor or switch that has failed, but I don't know where to start looking. One thing that bears mentioning is that I believe my intake air sensor is failing. I've received an intermittent check engine light, and when checked, flashed 11. I don't think it's related (it has been happening for the better part of 3 months now), but I thought I would bring it up anyway. I also replaced my O2 sensor a few days ago.

Any & all help would be greatly appreciated!

-Mike

mightyslash

The fans will automatically come on in 30-60 secs after you turn it to the accessory position? I dont think that's true. After turning the car off, the fans will only come back on automatically when 1) your car runs too hot. 2) you turn the key to the accessory position and turn on the blower or A/C.

user 84205

Agreed, I just think it was chance that your car was hot before so your fans were coming on. As for the FANs coming on with the A/C that always happens.

Also whats your mods? Do you have a power FC or any aftermarket computer? I can possibly help you with the engine light flashing...

mightyslash

Just make sure the fans dont come on right after you turn off the ignition. Another way to check to see if your radiator fans are working is let the car idle for a minute or two when it's warmed up (A/C and blower off)and wait for them to come on.

rotorhvn99

Quote from the fan FAQ on Steve's site:

http://www.scuderiaciriani.com/rx7/fan_test.html

Q: When I shut the engine off, the fans were not running. Shortly after that I turned the ignition on but didn't start the car and the fans came on. Why?

A: The fan circuitry works the same whether the engine is running or not, when the ignition switch is on. After you turn the engine off, coolant stops circulating. Without circulation, it heats up to the point of tripping the temperature sensors that run the fans. So when you turn on the ignition, the sensors say "run the fans" and the ECU complies.

rotorhvn99

I have a Pettit Unlimited ECU. I'm not worried about the Check Engine light as I already know the cause but just haven't had the time to fix it. I'm suspecting my temp sensor on the back of the water pump. I have a new one of those already that I'm going to install over one of the upcoming weekends.

-Mike

rotorhvn99

This is my problem. They run fine with the A/C on, but do not come on otherwise. In my original post, I mention that I let the car run & run. Once I turn on the A/C, the fans kick right on.

-Mike

djantlive

Your fan relay (or thermoswitch in Mazda's terminalogy) may be faulty, causing the fan not to come on.

Code 11 is the intake air thermosensor. It fails commonly. It's under the UIM. I don't think it has anything to do with your fan not coming on. This sensor is designed to help your can run at the right air/fuel mixture. Not sure if this is caused by your Petitt ECU. If it's not, you should pull the UIM (don't need to do it completely but just get it off about 2 inches) and you should see it. Download a shop manual from Mazdaperformance.com to see where it is before you start on the job.

rotorhvn99

That's what I'm thinking... I already own a shop manual & have just been too lazy to replace the intake sensor. I figure I'll do that when I get around to changing my spark plugs & wires.

-Mike

user 84205

You know right if your sensor warnings are on and you have a PFC, it will make your engine lamp flash right????
I had it happening all the time for my Knock sensor, so I just turned it off. WOW no more light... hehehe

GoodfellaFD3S

iTrader: (213)

If you don't use your a/c, you can always just pull the relay located near the front of the engine bay. That'll allow you to run the fans (without actually engaging the a/c) whenever you'd like. That's what I do in the TX summers here. Hey, I don't have a/c, but it just saps hp and hurts fuel consumption; 2 areas I like to keep at optimum levels

(plus, if I ever need it to take a chick on a date or something [yeah right ] I can always throw the relay back in)

rotorhvn99

That's exactly what I've done for the time being. It's just going to be a pain in the *** to replace the switch I need to replace. So I'll live like this for a while...

-Mike