fan radiator problem

[lookin]

I knew it!

Yes that could be the problem. Restore that ground.

[c2xejk]

Quote:

Originally Posted by lookin Couldn't part of the relay, be bad though, since there is more than one simple on off circuit in them? I mean, my relays, all have 5 contacts on them. Are the older style relays different?

The relays I am familar with have 4 terminals. 2 for the control side. 2 for the output side (switch). Not sure why they would have 5 terminals unless there is a normally open (NO) and normally closed (NC) terminals...

Either way, if ECU is able to turn on the fan, it is able to turn on the fan. Issue would seem to be with it's ability to correctly read the CTS. Might try disconnecting and reconnecting the ECU connector and any other connectors in the circuit. If there is any corrosion on the terminals, that should clean it.

[Screamin4banger]

Quote:

Originally Posted by c2xejk Issue would seem to be with it's ability to correctly read the CTS. If there is any corrosion on the terminals, that should clean it.

+1
YES

This is evidenced by:
More than one CTS behaving in the same manner.
Heating the CTS to an extreme range.

Remember that the CTS is a thermistor, and any other resistance in the circuit will add to the resistance across the CTS.

to really test the CTS you would need to ohm it out cold and then ohm it out in hot water with a temp probe.
If the CTS ohm's out ok, then it becomes clear how additional resistance in the circuit will affect what the ECU sees.

[DustyR/T]

mine does the same exact thing, and I performed the same exact tests minus your torch test. I did change the sensor and the problem still persisted. It will get to the 2/3 line and just above that sometimes before the fan kicks on. I have tapped into the factory wiring w/ a 30AMP led toggle to kick the fan on when I anticipate idling for a period of time or driving very slowly. My job, Advance Auto, sells a kit w/ sender probe and adjustment box to kick on the fan when you want. It's about $25. If it's bothering you that much, just get that and be done w/ it.

[lookin]

Thanks Ed. Oops. My bad. My relays only have 4 tabs. You're right. People need to make sure their relay contacts are clean.

Dusty, for a manual fan switch, I just ran wires, from the fan relay to the toggle switch, that I installed on my dash. I use it to pull air through my ATX cooler, when my ATF temp gage shows the fluid in the pan, is heating up too much.

All carzbozs has to do now, is to restore his missing engine to firewall ground, and that will fix his problem.

The CTS, can't trip the fan relay, if there is inadequate engine ground. I replaced my wimpy engine to firewall ground wire, years ago, with a much heavier cable.

[Ondonti]

I am not seeing how the engine to firewall ground will cause this problem.

I just hooked a wire that has two clamps on it then a switch in the middle to my fan to make sure it works (it does) and now I am going to mess with seeing what is not working.

One of the wires on my fan (the power wire) seems to have been loose. The person who crimped them together previously did a bad job but I dont know if that solves my own problem.

[lookin]

Brent,

Well, one of those temp sensors only has one wire, and so wouldn't it be totally dependent on the engine itself for ground? Same thing goes for plug wires. A circuit is only as good as it's ground. That's why I beefed up my engine firewall ground and engine to negative battery wire.

Maybe I am full of beans though. I dunno.

[c2xejk]

Quote:

Originally Posted by lookin Brent, Well, one of those temp sensors only has one wire, and so wouldn't it be totally dependent on the engine itself for ground? Same thing goes for plug wires. A circuit is only as good as it's ground. That's why I beefed up my engine firewall ground and engine to negative battery wire. Maybe I am full of beans though. I dunno.

The one wire sender is for the gauges. Lack of proper grounding could cause "percieved" issues. Hence I was asking "why" he thought there was a problem. And why I recommended he check the actual temperature with an aftermarket gauge...

[lookin]

OK. Thanks Ed. I knew it was one them thar temp sensors.

[Ondonti]

Well I didnt know the fan wouldnt turn on with the temp sensor unplugged unless the motor is actually running (key on is not enough ) so what I said makes no sense now.

[lookin]

Quote:

Originally Posted by Screamin4banger +1 YES This is evidenced by: More than one CTS behaving in the same manner. Heating the CTS to an extreme range. Remember that the CTS is a thermistor, and any other resistance in the circuit will add to the resistance across the CTS.

That is why I said that carzbozs needs to replace that missing engine to firewall ground wire.

Although things will work with just the engine to negative battery wire, there will be a voltage drop and increased current resistance, in the circuit, which btw includes the entire engine block.

It is also silly to put on good low resistance wires and hot coils, only to leave on the, wimpy, stock engine to negative battery and block to firewall, ground wires.

[Ondonti]

What is the sound that is made when you unplug and plug in the CTS when the Key is on but engine is not running?

Sound seems like it comes from the plenum....

[lookin]

hmmmm

The only thing I can think of, is that maybe, the AIS motor is activating.

[Screamin4banger]

Quote:

Originally Posted by lookin Quote: Originally Posted by Screamin4banger +1 YES This is evidenced by: More than one CTS behaving in the same manner. Heating the CTS to an extreme range. Remember that the CTS is a thermistor, and any other resistance in the circuit will add to the resistance across the CTS. to really test the CTS you would need to ohm it out cold and then ohm it out in hot water with a temp probe. If the CTS ohm's out ok, then it becomes clear how additional resistance in the circuit will affect what the ECU sees. That is why I said that carzbozs needs to replace that missing engine to firewall ground wire. Although things will work with just the engine to negative battery wire, there will be a voltage drop and increased current resistance, in the circuit, which btw includes the entire engine block. It is also silly to put on good low resistance wires and hot coils, only to leave on the, wimpy, stock engine to negative battery and block to firewall, ground wires.

While I do agree that engine grounds are very important, I don't see how they are going to help with a sensor that does not ground through the engine.

Here is what I mean. This is a typical CTS diagram, although not from the Mitsubishi 3.0. I do not believe the Mitsu motor is going to be that bass-ackwards that it will need to ground through the engine.

[lookin]

I already agreed earlier, that the two wire CTS, is not engine ground dependent. So that isn't what I was on about.