Ok guys well I want to get a new fan switch for my header swap.

I know that you do not want to run too cold with fuel injection, and plus too cold of an engine leads to engine damage (not supposed to rev a cold engine high)

Would the JET fan switch that comes on at 195 and goes off at 185 make the motor too cold for the computer?

 

No, but if you just order one for a Grand National (206 on, 180 off I think), you'll save some cash. A motor has to run pretty cold for it to be too much, say less than 150 F. Most find that heat on cold days becomes questionable with less than 170 F operating temp, however. Closed loop actuation is more affected by start time (for 02 heating up) than coolant temp, and generally isn't an issue, its mostly a myth unless you're trying to run below the 150 or so stated above.

 

My motor runs at the line before 220 in the stock gauge, that is 200 right? So even with the jet one i will hit closed loop with no probs right?

 

Well, the stock gauging is notoriously inaccurate, so I can't say really what you're running at. A scanner would give a better idea of what the motor is really running at. For comparision, I run a 180 thermostat and Grand National fan switch, and it runs at about 190-200 idling most days (higher on hot days, but the primary fan set for 220 almost never has to come on), less than 190 when cruising. It goes right into closed loop like stock and stays there like it should. Hope this helps.

 

to save some money get a toggle switch and wire it to the fan relay ground then you can control when it turns on and it will only work with key on so you wont have to worry about shutting it off.

 

how can u tell it goes into closed loop?

 

The best way I can tell If in closed loop
without a scanner or anything at all is
having the car in "D" and hold the brake.
The idle should drop down to your minimum
air idle speed (450-500rpm)

The car wont do that when cold, at least
my car. So, usually there is small change in
the way the engine runs when its using
all of the information from its sensors.

Other than that, good question! I wanna know too

 

Go with the Grand National switch and the 180 thermostat like Detroit Z28 suggested. I guarantee you won't have any problems with it going into closed loop. I run the stock, 195 thermo on my 89 TBI during the winter for really good heat inside the car, but I switch to a 180 every summer to keep the engine cooler during the hot months, and I've never had a problem with it going into closed loop. Just make sure to use the 180 thermo with that fan switch though. If you keep a 195 in there with the lower temp switch, your fan will run continuously. Ask me how I know.

 

Where can I pick up one of these grand national fan switches? My concern was the wiring to the switch is shot too.

 

Just go to an Auto parts store and ask for the fan switch for one of the Grand Nationals in the 80's, like an 87. It's usually like $20 or so and looks identical to the stocker. If you're wiring is shot, go to a bone yard and cut that pigtail out (unless said parts store can order that too).

 

Ive ran into many fan switches that are not truely a GN fan switch even when ordered correctly. I ended up going to GM to get one because the NAPA, Advance, Autozone, Bumper to Bumper switches were all wrong. Of the parts store switches the lowest turn on was 214 I think. Make sure you check the paper catalog for the temp before ordering it.

 

You never know what you're going to get sometimes, that's for sure. I paid too much for the Hypercrap fan switch, and it doesn't even come with the right connector for an f-body. I had to cut off my original connector and splice a different one on to use it. At least with the GN switch, it should have the right connector, and only cost half as much.