KZ1

After 64k miles, and over a year of ownership, I have my first thing go wrong on my RX-7. Here is the deal, hopefully you guys can simply save me some time.

Since getting cold outside, my car never heats up past 79C, not even enough to get out of the fuel enrichement compensation mode. ANyway, I thought maybe thremostat open, however yesterday after driving for 30 mins in stop and go and highway driving, I stopped the car, and noticed my fans were on. Fans on at 79C, WTF? I shut the car off, and they are still on??? remmebr I have no fan mod on this car, everythign is stokc on cooling system. I know the themostat is wokring because at it hit 80C once and bam I got heat out of heater, and manual says that is the initial opening point.

I am thinking the problem is my colling fan relays, there are four of them. I am going to test them all, but does anybody know which one is most probably the culprit, or doers anyone have a description of what each one does? I just want to save some time. Also, has anyone experienced this before?

Thanks

Bacon

iTrader: (12)

well theres a good break down of the relays on dave disneys site under the fan mod how 2...but i wouldnt suspect the realys, all the relays are is a swich that turns on a high current motor.. (basically not to have 8gauge wire runnin to the ecu they can keep usin 22 or whatever it is) thats wierd my car did soemthing similar once ..the no heat...but if i went out and got on it for a bit after it was "fully warmed up"..boom id get heat...
but you should be able to heat up past 79 even with the fans on unless..damn how cold is it there?
but honestly id look @ whats controllin the relays the fan ecu &ecu...the work on from ther..sorry i couldnt help more
http://www.rx7.voodoobox.net/

spyfish007

well with the heater on and a bad thermo switch the fans will come on medium ... and I suppose on a cool day this might remove enough heat to keep the system this cool .... however do you have the stock thermostat? I can't answer the fans on after you turn the car off though ....

spyfish007

oh yeah ... you can see the diagram on B-2 of the wiring diagrams (section Z-40)

KZ1

thanks guys, I am going to go at it this weekend with the shop manual and a voltmeter. But here are so more details. The thermo switch is obviously telling 79 C, becasue I can read it on my PFC, which means the ecu is not telling the ffans to come on. Secondly, those with PFC knows when the fans are on because the Electrical load led is lit up. Well, figure this. Fans are on, but ELD is not on the commander. SO ECU know nothing of fans being on. That is why I am guessing it is a realy stuck, or short, etc.

Wish me luck I hve like 1 hour to fix it before I am supposed to take this dig for a ride in the beast.

Flybye

Yeah, that definetely sounds like a sticking relay.

I'd remove the relays and see if power which is supposed to enable the relays is going towards them. You might even have a problem with the PFC or possibly a frayed wire.