Install of Water Temp Gauge

[jramosGT]

In my '03 GT I'm planning to istall a boost gauge and a water temp gauge on a A-pillar dual pod. Looking at the 2003 manual, it reads, "The ECT (Engine Coolant Temperature) sensor provides an input to the PCM (Powertrain Control Module).... The ECT sensor provides input for various PCM operations. The PCM uses the input to control air-fuel mixture, timing, and radiator fan on/off times. The PCM uses ECT sensor input to end messages over the PCI bus for temperature gauge operation."

The electrical water temp gauge I have requires me to install a different temp senor in place of the OE unit. From the above that doesn't sound like a very good idea. Any opinion if I can do one of two things:
1. Just tap into the wire of the OE unit to feed a signal to the aftermatket gauge. What info (reistance?) do I need to determine this?
2. Replace the OE ECT sensor with the aftermarket sensor, and tap into that for the PCM feed.

The first sounds more reasonable than the second.

Or should I just install a voltmeter instead of a temp or pressure gauge?


Jumpin' Joe
Onyx Green GT

[bobs turbo pt]

hey joe, like you said The first sounds more reasonable than the second

[Cal Cruzer]

I haven't done any work on my new car yet so I have no idea how much room there is around the sensor, but on mustangs some people were able to put a T where the senor was and run both sensors. Also some would tap the outlet to the radiator and screw the sensor in there. Wish I knew more about these cars...I will learn.

[bobs turbo pt]

a t might be a good idea !!

[jramosGT]

OK, I'm down to drilling and tapping to install the AutoMeter sender for the water temp gauge. I had thought of just inserting a "T" where the OE sender is to accommodate both senders, but after looking at the manual (need to remove the engine torque brace), and looking in the engine bay and seeing that I may not have room in there for the "T" decided to do this.

Is the radiator filler neck plastic or aluminum? It's black rather than the silvery color. I can't tell by tapping on it. Also, will I get a true reading if I tap into it there?

Jumpin' Joe
Onyx Green GT

[earringboy]

...look at the areas around where the turbo cooling lines that carry the coolant too and from the turbo from the engine block. With these 4 choices of location it appears on mine that a tee fitting and short nipple could be fit, the block also has several threaded plugs that can be removed that are into the water jacket. Do not change out the factory sending unit and it will probably not work with aftermarket gauges...the radiator is a poor choice for tapping threads, it is thin and the plastic probably won't hold the threaded sending unit because of the weight and vibration...now if you have a 5-speed you might use the radiator connections that are for the trans cooler that isn't being used and with an auto-stick you might could use one of the coolant circulating lines for the trans with a tee fitting...just try and stay as close to the block as possible to get the truest reading also try and find brass or stainless fittings so you don't get rust...

[GTcamster]

my idea on this would be to tap into ether the turbo cooling lines or one of the heater hose's with a brass fitting. but then again looking at the therostat cup, it looks like theres a air bleeder in it to bleed off air locks. that might be an idea..?

Deep Cranberry Pearl Coat GT ~ 5 speed