LS1 in a 3rd gen question
LS1 in a 3rd gen question there are very few things keeping me from driving my car. the one that is getting me is the temp sender. the sender that is on the LS1 reads all wrong for the gauge, so i have to install the stock one from my 305. it appears to be a 14mm thread. is there some adapter somewhere that will adapt from the thread on the port of the passenger side head to the thread of the sender? or does someone know of a sender that is the same thread as the LS1 that reads like the 3rd gen? or do i just have to drill and tap for the sender? if so where is the best place?
TECH Enthusiast
Joined: Jun 2004
Posts: 544
Likes: 0
From: Itasca, IL
Hmm, my temp signal works perfectly with my stock guage. Are you taking the wire that comes from the PCM or does it come directly from the sender? I have a speartech harness, and he has a wire labeled "water temp" that I believe comes from the PCM.
Well the temp sensor for the LS1 was different from 98 to 99-02. The 98 has a 3 pin temp sensor and one of the pins is for the gauge, so on my swap i replaced the 02 sensor with a 98 sensor and used a 98 sensor pigtail and ran my gauge off that. If you have a 99-02 it only has a 2 pin connector and goes directly to the pcm, but you may be able to get the signal from the pcm for the correct reading like 92CRS stated. What year LS1 PCM are you running and i will find out which pin coming out of the pcm it is??
Joined: Sep 2004
Posts: 3,148
Likes: 12
From: Downers Grove, IL
There are a couple solutions depending on what year your motor/PCM is. If it is a 98 then connect the temp gauge wire to connector 220 pin K dark green wire. I do not have full diagrams for the 99-02 but the way it looks in my pinouts the temp sender signal is sent to the dash as a serial data signal. There is a spot for a second sender on the passenger side head near the back, it is 12mm x1.50 thread, autometer, and a couple other companies make an adapter to go to 1/8" NPT. But if your sender is like mine it`s 3/8"NPT, You can either drill the head bigger and rethread it or I put my sender in a lathe and cut it down. The sender is made of brass so if your good you could probably cut it down with a drill and file and then use a 12mm x 1.50 die. You could also put a 98 sender in it and use the 3rd wire to run your gauge, but I am not positive that the output will be 100% accurate with your gauge and a 98 sender
