Changed ecm, fans not working?
 

Hey fellas. Well, I exchanged my ecm under a 1 year warranty from autozone.. The car runs great and I think the sparatic running issues are over. However, I remember he cooling fans coming on upon turning the key on... They don't now. Also, the car got up to 220 degrees warming up in my garage and the fans never came in... What gives? Can't be another bad ECM!!! This car is starting to drive me crazy.. Oh, it's a 88 iroc, 350 TPI, bone stock

Re: Changed ecm, fans not working?
 

The previous ECM was likely in limp mode, which will run the fan all of the time.

IIRC, the ECM will turn on the fan at about 226* - 228* F, so the engine wasn't hot enough yet.

RBob.

Re: Changed ecm, fans not working?
 

That explains it. Thank you. Those temps seem very high for the fans to start cooling. I'd like them to come on at about 180-190. I guess there's no way of adjusting that short of getting a custom chip?

Re: Changed ecm, fans not working?
 

If your going to go the route of burning a new chip just to control your fan temps, your better off just getting a system that can control all aspects of your tuning for you down the road...

As for something that can control your fan temps w/out burning a new chip, a JET fan switch will turn your fans on at a much cooler 195 degrees then off at 185 degrees...

http://www.jegs.com/i/JET-Performanc...60600/10002/-1

Re: Changed ecm, fans not working?
 

I was considering getting a chip for performance reasons, but I may just leave it alone at this point. That jet fan switch might be just what I need. It looks as though it plugs into the tock relay?

Re: Changed ecm, fans not working?
 

The Jet switch does get wired to the stock relay, just the one wire to ground the coil and enable it. The current connection to the ECM can remain, as they both just provide a ground to the relay coil.

A 350 TPI is likely a dual fan set up, and you did post 'fans' (plural).

Since they were both running together with the bad ECM someone has likely changed the wiring for them. One of the fans is ECM controlled, while the other fan is head switch and A/C pressure controlled.

Even with the wiring change the Jet switch can be used.

RBob.

Re: Changed ecm, fans not working?
 

I was wrong in my previous post. Only the one fan would come on with the key. Not both. Thanks for the info and help. On a side note, I fired up the car today for the second time with the new ecm. I now have a check engine light. We're preparing for a blizzard that is supposed to arrive tonight into tomorrow, so I don't have the time to do the paper clip trick and read the codes.. But tomorrow I'll go back out there and give it a go. I'll post back with the codes. Thanks again

Re: Changed ecm, fans not working?
 

We got clobbered today, they just lifted the ban for driving 30 minutes ago, and since then we got an additional 3 inches of snow here in Middlesex County and its STILL coming down! If anything bad happens during the commute, then I can assure you that Christie seriously hindered any presidential aspirations he has. That big freaking shmuck will never learn...

Re: Changed ecm, fans not working?
 

Wow, we barely got anything in ocean county... The roads where perfect agin by lunch time..be safe out there.