DuffMan

iTrader: (1)

Will the ECM run the car rich or anything if I leave the fan on all the time? I leave it off until it heats up to 160 (I have a 180 stat)and then I turn it on and it doesnt really change unless I am running it hard in the afternoon. If i drive normal in the day or night, or even race at nite, it doesnt really climb any higher than 160. Could this cause the car to think it is still heating up to normal operating temp and run it rich? Will it cause any other problems?

Thanks a lot in advance!

Danno

Many times I say the same thing, these cars as well as just about any vehicle in the last 20 or so years were designed to run at the stock temp of 195. All fuel delivery and emission equipment work best at 195. Running the fan all the time will chew up the fan motor and cause premature alternator failure. I tried every different stat and my 5.7L got the best fuel economy at 195. Most people will disagree with this and claim all sorts of things to the benefit but think about this. One third of the energy in combustion is used for power, one third goes out the pipe and the other third is generated as heat into the block. Why do you think auto engineers from all companies are experimenting with hotter running engines? Yes, for emissions-but less emissions means more complete combustion hence more usable energy. Problem now is that material limitations are making progress slow for more efficient engines. When I ran anything but a stock stat I lost typically 3mpg and it tended to run rich. On a non-electronic managed engine you can basically run anything you want. Thats why lots of guys go back to a carb because it gives the a wider ramge of options. With an ECM controller it is designed for a target temp of around 200 degrees. Even my sportbike has a 195 stat, and YES I tried messing around with it. It would not run right and I put it back to stock and she's just totally sweet.

DuffMan

iTrader: (1)

Wow, a lot of information to take in :-)

My fan is not working, only when I turn the A/C on, so what steps should i go about, ranging from easiest to hardest to check what the problem is?

Also, is the fan switch between the #1 & #2 cylinders on the drivers side of the block?

Thanks!

Danno

The device on driver side is the temp guage sender, the fan switch is located on pass side between cyls 6-8. The fan switch has a single dark green/wht wire going to it. You can take off that wire and simply ground it with the key on(engine can be off). If the fan runs the switch is bad. Normal fan switch on temp is approx 225-238 degrees.

DuffMan

iTrader: (1)

Ok, just so I dont pulling out knock sensors and what not , is this the order of the cylinders?

8 7
6 5
4 3
2 1

Thanks!

camaronewbie

Duffman:

Crawl under, pass side ... there are two wires running to two items (besides plugs). The lower one (to the ground) is Knock sensor - it's also bigger around. The fan switch is harder to reach (higher up) and smaller around, and like was already said, has green/white wire running to it. Both knock sensor and fan switch have same connector type.

Also, don't buy the trash from Auto Zone ... I just replaced mine from there and it doesn't work. Spend the bucks on the real deal - GM is $30.02.

But first, check and see if fan runs when you ground wire from fan switch (with key on). Also check fan relay (ground the green/white wire with key on) - relay is on driver side firewall.

AND ... make sure car is cool first! Mine was hottter than I thought, and I got a nice burn when I replaced fan switch from the coolant that spewed all over me (plan on replacing alot of coolant).

I would check relay first, then switch, then sensor. Relay is cheapest ($10), sensor probably not necessary unless car runs rough ($20), and a good switch most expensive ($30). Hopefully it's the switch or relay (cheap fixes). In Vin Code F engines I think the ECM started controlling fan functions as well some how - my 90 RS (Vin code E) doesn't, but ALLDATA schematics suggest that Vin code F engines has ECM input to control of the fan. Just check sensor/switch/ relay first - much cheaper fixes.

If you need to run fan constant while key is on (until you trace real problem), then splice into green/white wire on relay and ground it - this "straight-wiring) won't blow fuses.