Couple idle questions

[Chihua33]

As far as I know, they are connected?

I've never checked to see if the connection is dirty though

[4uall]

That's true Jay, but most people don't use that method. Mainly because you have a brass plug screwing into aluminum and it very easy to strip the threads. Also you'll see that the small hose at the throttle body preheater is at the highest point in the system on our FI cars, so even if you used the plug you'd still have to top it off there to get all the air, which rising to the top as you fill. The coolant flushing T installed in the highest heater hose at the firewall is how most people fill the system, it being the highest point for all the cars that aren't FI. I'm not saying you can't use the brass plug, I'm saying it's a lot easier to top off the system with the T in the heater hose, which is pointing staight up instead of angled like the plug is and at a higher point in the system.
Ron

true true Sadly I do not have the throttle heater or a T flush and this method was all I could do however, it worked and continues to do so I love these cars because of the very unique reactions they give each owner


IMG_0746 by itzebtze, on Flickr


New spark plug wires installed by itzebtze, on Flickr

[rlux4]

Keith means to connect them to each other: loop between the male and female connector end that's not connected to the sensor when you pull them apart. What that would do is bypass the temp sensor. If your fan runs when you hot wire it and it doesn't run if you jumper the two wires for the sensor then you either have a bad ground or a break in the wires. These wires act as a loop for the ground wire. Instead of going straight from ground to the fan, the wire splits and goes down to the sensor and then up to the fan.
Ron

[So Cal Mark]

A very important note on the position of the water tee! When you flip it over so the temp sensor is on top, you have positioned the restricted side towards the radiator, drastically reducing the flow of water to the radiator! I have 2L car in the shop right now that was purchased that way, and of course the headgasket is blown

[RRoller123]

Mark: So the plug and sensor threads are not the same? I.e. the housing on mine must have been installed upside down? My car runs fine and I have been just removing the sensor (carefully of course, to fill and bleed). I know what tomorrow's project is depending upon the answer to this question! <{:^)

Regarding filling the system through the throttle plate heater: Even though this is the highest point of the system, filling the entire system here doesn't work on my 2L. I only was able to add about 12ozs before the TPH lines were full and it started to flow out the heater. Afterwards, I was able to add maybe another quart or so through the bleeder plug hole. There is probably some flow restriction involved that I am unwaware of, but that is the way it worked on mine.

Pete

[Chihua33]

So the po had a hack job on the wires for my fan sensor so it's just bare wires connected. So there's a chance I got them back together switched correct? I let the temp run up and no fan came on. I don't have a meter to test anything...

[Kent124]

When you flip it over so the temp sensor is on top, you have positioned the restricted side towards the radiator, drastically reducing the flow of water to the radiator!

To clarify, what you are saying is that the unrestricted side of the tee connects to the top radiator hose while the restricted side of the tee connects to the thermostat hose. Correct?

[RRoller123]

I guess I am going to have to jack this thing WAY up tomorrow and see what is going on in there. What a mess this is going to make, and it will probably be the 4th time in the last month that I have had to fiddle with the cooling system to get it right. LOL. If I don't hear back from anyone about the threads being the same or not (?), then I think I will first just try to carefully swap the position of the sensor and the fill plug. The bottom position will put more of the sensor into contact with the coolant, assuming that there must be some small amount of air along the top. The car runs perfectly (regarding cooling) and heats up per normal schedule and temperatures, so I would be surprised if the housing is on upside down. But.... the PO did do a lot of coolant work, new water pump, etc. so anything is possible.

Pete

[rlux4]

I never used the preheater hose to fill the system either, too slow.
My attitude is whatever works best you is the way to go. I do it the way I do because I got tired of lifting the front of the car to fill the system. One time at an Mirafiori Oregon campout I drove up a bank, putting the car at about a 45° angle and it still didn't work. After that is when I installed the filler T and drilled the stat.
Ron

[RRoller123]

I am only going to jack it up this time to avoid losing too much coolant when I take that housing off to see if the PO put it in the wrong way around. What a mess that coolant makes, all over everything, and we with pets all around. Engine then smells of it for days. ughhh...

[RRoller123]

Well the mystery as to why my temp sensor was on the top of the T where the bleed plug is supposed to be is solved. The T Union has a restrictor as Mark warned, and it was installed correctly, with the restriction side towards the thermostat.

Here is the unrestricted side:



Here is the restricted side:



I suspect that some of the inexplicable overheating problems that people are asking about may be due to this? The T Union can easily be put in upside down. There are no markings. And the threads are the same for the Temp Sensor and the Bleed Plug, so those can go in either position. On my car, the Temp Sensor was in the top position because it would not fit in the bottom position due to interference with the radiator fan bracket. The PO put in a new radiator and it sits higher than stock. So his mechanic just put the sensor in the top spot. I made a simple bracket to rotate the radiator just enough to allow the sensor to fit without interference.



And now it all makes sense.



A quick note on testing the Temp Sensor. If you keep it mounted in the T Union and put the union it in a small pan of water on the stove, you can stick the plumbers thermometer in the union next to the sensor body and it can sit there by itself and it frees up your hands to use the multimeter as you watch the temperature rise.

The data from mine:

At 68 deg F, s/b: 2,000-3,000 was 2710 ohms
At 122 F s/b 700-1000 was 870 ohms
At 176 F s/b: 200-400 was 325 ohms
At 185 s/b: <200 was 250 ohms.

Not sure if this last reading is a problem or not? Anyone else test their sensor and have similar results?

Pete

[rlux4]

Those numbers look good to me. I'm betting you don't have trouble with the engine warmed up. The ECU will no doubt respond to anything less than 350 ohms or so with the same response.
Ron

[RRoller123]

Thanks Ron. I actually do have an odd issue that I am trying to sort through. The car starts to miss after about 40 minutes of driving. Runs well and then starts to miss, but doesn't stall. Will respond well to throttle and has plenty of power. I suspect maybe the fuel pump is going wonky as it heats up? Not sure. But I did notice this afternoon that the car seems to idle better now with the sensor in the correct bottom position, (including through fan cycles) probably because the sensor stalk was not fully immersed enough in the coolant with it mounted on top. (?) I haven't had time to take it for a drive though to see if there is any overall improvement.

Pete

[bradartigue]

I got mine to idle at about that when in drive. But in park it goes up to 1200ish is that okay? I took it for a ride and it ran real good! Temp stayed at 190 but when I got home let it idle and it kept climbing with no fan kicking in. I hit wired my fan and it does work. All rad hoses are hot. So does this mean bad stat?

190 is normal. Fan should kick on around the "0" in 190 and turn off once it is back at "9". No fan running is bad, fix that first, it is either the wiring to/from the fan switch or the switch itself. Easy to fix.

Your car isn't idling correctly, fix that too. Probably the o-ring on the idle bypass screw, a leaking AAR, or some other air leak. But diagnose one thing at a time. Read the FI section here: http://www.artigue.com/fiat/tuning-book

[bradartigue]

On my car, the Temp Sensor was in the top position because it would not fit in the bottom position due to interference with the radiator fan bracket.

Carbureted fan in a FI Spider. Probably replaced years ago; they all interchange and put the fan in different positions, low, high, left, right...but oddly never in the middle!