Engine/Transmission (1994 - 1998) Add Pre-Turbo Pyro

[MNorgren]

I have my egt prob currently in the post turbo. I ordered a 2nd prob to install pre-turbo.

My Question: Can I add this one to my current gauge with a toggle switch to get post reading for cooling turbo?

I've read articles about not cutting the prob wires since this will make a faulty calibration. Just wanted to know if anyone has experience with this.

 

[SRadke]

You would have to buy a thermoucouple switch to do that. The contacts in the switch must be made of the same material as the legs of the thermoucouple to get accurate readings. Thus far I've had no luck finding such a switch that would realistically work.



-Scott

 

[NHouse]

I have two probes and one gauge, it works very well. I usually leave it switched to pre-turbo, but I do use the post turbo probe for shutdown temps sometimes. I bought a DPDT switch from Radio Shack. Don't cut any significant length off of the thermocouple wires, but you may have to cut the ends off and crimp on new ones to make them work with the switch.



I did some testing when I made my setup, and found that the resistance the switch adds is insignificant and won't affect the reading of the gauge in real world situations. Even if it did, the switch adds more resistance in the circuit, so you will always err on the safe side as far as temp readings go.



I would go ahead and do it, I really like having probes on both sides of the turbo.



Nick

 

[MNorgren]

Nick, where did you tap into the harness to add wiring for the switch?

 

[NHouse]

I'm not sure I understand your question, the thermocouple wires go to each each side of the swich and the wires to the gauge come off the center. Just make sure you keep all the reds on one side and all the yellows on the other side. When you have the switch in your hand it will make more sense.



Nick

 

[MNorgren]

Thanks for the info!