engine cooling fan signal

[chris c]

i know i asked this earlier but i assume not here, can't find the thread.

i was interested in having the cooling fans come on at a slightly lower temp. asked if i could install a lower temp coolant temp sensor, etc.

for some reason i was told it was not possible, but you modified guys surely have the fans come on early. do i have to buy a programmer and flash PCM??

[J Wikoff]

You'd have to either change it in the PCM programming, or wire in a switch to ground the high speed fan relay, and turn them on when you want, and they'll still turn on normally at the PCM requested temp.

[chris c]

can you recommend a decent programmer for this car...

what is average cost?

[J Wikoff]

I think you're more likely to need a custom tune/burn from sinisterperformance.com. They are pretty reasonable.

[willwren]

You can't buy a programmer in the traditional Series 2 (OBD2) sense, since your car is not true OBD2.

Sinsister Performance can burn your eprom for you, or you can do the high-speed fan override as mentioned. I have that on my 93 and 95.
If you want to get creative, you could run that switched ground for the high speed relay through a temperature switch of your own, triggered either by a certain outside air temp or by coolant temp.

[chris c]

feel a bit better today, used a IR thermometer while running the engine and letting the fans cycle. despite a 220* reading on the dash, i was hard pressed to find anything over 202* on the engine [save for the headers of course].

[willwren]

With a non-contact IR, the closest spot to measure would be the coolant sensor under the throttle body, but it's very close to the exhaust crossover. The closer your measurement, the more accurate. They all measure in a 'cone'. The farther away you are, the larger area it's averaging. Temperatures can vary inch by inch on that manifold near the sensors.