fx400 radiators and fan switches again

Message

NRath · #21 Post by **NRath** » Fri Nov 07, 2008 4:01 am

Yeah, after thinking about the whole 1000 system, a resistor won't work since the ECM uses the temp as a factor in calculating fuel output. In that case, changing the temp reading of the sensor may cause more tuning problems than actually doing any good. Adding a resistor will change the resistance of teh sensor. When the ECM translates the voltage in the temp circuit to temperature, allowing you to tweak the resistance and fool the computer into thinking your coolant is at 195 instead of the 175 it's actually at- then it kicks on the fan like you wanted. Problem is it would also tweak the temp when it's cold, too. It would basically just put an offset into the sensor.

As for the MC500, if it is just a temp switch that opens and closes, a resistor does no good there either.

I'm going to shut up now and head back into my hole.

wistech · #22 Post by **wistech** » Fri Nov 07, 2008 5:17 am

Good info. I actually used resistors in temp sensor plugs to trick ecms on diesels so i could do cold power balance tests. They had to be at operating temps for the diagnostic link to start the test but weak cyllinders showed up better with a cold engine. Now I understand what you were getting at. Thanks,
I think Boomer has solved our issue.

wistech · #23 Post by **wistech** » Sun Nov 09, 2008 1:12 am

Boomer comes through yet again.

wistech · #24 Post by **wistech** » Sun Nov 09, 2008 11:16 am

One thing I forgot to add is the 1000ecm doesnt need to be fooled into turning the fan on with a resistor in the sensor as you can set the fan on temp in the map.

wayneschofield · #25 Post by **wayneschofield** » Tue Nov 11, 2008 7:36 pm

I checked today, there are loads of fan switches with M14x1.5 thread to screw into the rad drain plug hole to allow using the MC1000 type rad with the 500 ECU.

There are various connector styles, some with open 7.3mm spade terminals and some waterproof styles. Ther are various temperature ranges from over 100 deg switch on to less than 80 deg ©. There are some interesting types that have two switches in one, one at a low tem and another higher up. I thought that could be used to switch the fan on and then a high temp light in case the fan didn't pull the temp down enough.

I bought one of these for a BMW E36 compact 1.9 litre. It has a 'semi' waterproof connector with three terminals for the high and low temps.

When I get five I'll put it in my quad and compare when it switches on versus when the stock fan does via the 1000 ECU.

If you want to check yourself there are lots of different ones from BMWs, Mercs, some GM, and some Rover (not sure if you get inflicted with Rover cars over there.....)

Dachshund · #26 Post by **Dachshund** » Thu Feb 12, 2009 7:46 pm

Looks like Caniboomer got you hooked up but if you still need a radiator, I just acquired one.

fearlessfred · #27 Post by **fearlessfred** » Fri Feb 13, 2009 12:43 am

QUOTE (Wistech @ Oct 28 2008, 10:17 PM) <{POST_SNAPBACK}>

I have 02 and 03 radiators for trade or will buy yours outright. You may have an fx400 radiator and not know it. There is a switch with a wire coming out of it on the lower right side of the tank facing rearward.

I have a fx rad. if your still looking for one