The stock 305 TPI ran the fans off the ECM via a temp sensor and a relay or something like that. When I did the 350 swap, I hot wired the fans to "key on" power, so they run all the time.

I read this will burn the fans out. Is there a way to replicate the factory fan setup without the computer so that the fans will only turn on when the temp goes above a certain setpoint? I've got a 165* tstat as well.

Also, the engine idles 900RPM nice and smooth in park. In gear at a dead stop however the idle surges from 700 to 900RPM, randomly dropping to like 600RPM. Any ideas?

Dave

 

You can get an aftermarket temp switch and relay to drive the fans, and most of them are adjustable so you can set them to whatever temp you want.



The surge sounds like a vacuum leak.

 

It's a fairly straightforward setup right? A sensor screws into the block runs to a relay which controls the fans, similar to the stock setup just independant. You wouldn't happen to know any place that sells such a setup?

If it's a vacuum leak, why does it only surge in gear, why does it idle perfectly in park?

 

Park is a no-load situation. Vacuum leaks and misfire issues are both less noticable under no load (except on EFI cars, when a vac leak nearly always causes a high-idle condition.)


The fan control is just that....a temp. switch and a relay. Some of the switches screw into the intake/head, but most of the aftermarket ones just have a probe that pushes between the radiator fins. Run a search on Jeg's or Summit for "fan control" or something similar.

 

Okay I figured it out and ordered the fan control kit. THnx

So the surging is most likely a vacuum leak....hmmm.

Thnx

 

Sorry for the hijack but I have been trying to reach you.

 

NP, I e-mailed you.