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ECM and cooling fans


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OK folks, sounds like it is time to get serious. <P>Wally: your test sounds like my car except If i stay in heavy traffic for long enough with an ambient reading of 95-96 it will climb past 200F. Anything over 45 and drops back to low 180s (180 thermo).<P>Sounds like your case is mild, mine in moderate, and Tom is over the top. Next question is "what is normal ?" I know that in testing GM considers 230 to be within the normal range.<P>OTOH I have found that engines seem to like to run cool and regularly run 160s in carburated cars and 180s in those wit5h computer controls. Batteries, hoses and belts seem to last longer.<P>I do agree the fans need to come on sooner and upshift to high at lower temperatures. Problem is that the last car (Fiero) I played with used a sensor to turn the fans on.<P>A lot of work has been done by the GN crowd in reverse engineering the chips and the low coolant fan seems to be at 3F0h (turn on) 3F1h (turn off) and 3F2h (turn off at mph).<P>Should not be hard using all of the work that has gone before to determine the Reatta maps if anyone has a dump of the PROM.<P>If this is not available, I can do it but have two difficulties:<BR>1) my equipment is for the C3 computers, not the P4. Need new prom hardware.<BR>2) do not have a Reatta ECM to take apart as yet.<P>If someone can help with (2) I will take care of (1).<p>[ 07-21-2001: Message edited by: padgett ]

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