LS1 and Autometer guages
1. Tach - I used the 12v source with the 680 ohm resistor and the tach is erratic and not acurrate. I called autometer and they said to use a 5V source and a 10k ohm resistor. It does not work at all. I then tried a 12v source with the 10k ohm resistor and the tach works pretty well. The problem is the voltage is back feeding into the pcm and the engine won't start or idle. I remove power from the tach line and the engine starts right up. So what is the answer????
2. Oil pressure - LS1 sending unit does not work at all. I bought an adapter and used the Autometer sending unit
4. Oil temp - so far the LS1 sending unit seems to be working ok.
5. Water temp - with the guage hooked up the computer thought the water temp was -30 on a 90 degree day. I disconnected the guage and the computer now reads 90 degrees as it should. Any ideas other than plumbing a seperate sending unit???
Any suggestions would be welcome.
Thanks
Mike
1. Tach - I used the 12v source with the 680 ohm resistor and the tach is erratic and not acurrate. I called autometer and they said to use a 5V source and a 10k ohm resistor. It does not work at all. I then tried a 12v source with the 10k ohm resistor and the tach works pretty well. The problem is the voltage is back feeding into the pcm and the engine won't start or idle. I remove power from the tach line and the engine starts right up. So what is the answer????
2. Oil pressure - LS1 sending unit does not work at all. I bought an adapter and used the Autometer sending unit
4. Oil temp - so far the LS1 sending unit seems to be working ok.
5. Water temp - with the guage hooked up the computer thought the water temp was -30 on a 90 degree day. I disconnected the guage and the computer now reads 90 degrees as it should. Any ideas other than plumbing a seperate sending unit???
Any suggestions would be welcome.
Thanks
Mike
Yes I used red 10 also in 4cyl mode....no dice! I am sure I will figure something out, I always do. I do know selling the car is not an option. Funny I only use the tach on the street. When I am racing I never look at the tach, When you hit the rev limiter it is time to shift.
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For oil pressure, I used the Autometer sender and drilled/tapped the plate just above the oil filer. For water temp, I used an adapter for the sender on the pass side cylinder head. My tach is originally a 4 cylinder model, and I hooked the white tach wire directly to it and it works just fine. Not much help I know, but that's how it all worked out for me.
Andy1
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As mentioned, I also tapped the aluminum part above the oil filter for the oil pressure sending unit. I believe it is an 1/8 NPT.
On the temp sending unit I took the plug out of the back of the passenger side head and carefully drilled and tapped it for the sending unit. It was pretty easy and I was just careful to drill in the middle of the plug.
As mentioned, I also tapped the aluminum part above the oil filter for the oil pressure sending unit. I believe it is an 1/8 NPT.
On the temp sending unit I took the plug out of the back of the passenger side head and carefully drilled and tapped it for the sending unit. It was pretty easy and I was just careful to drill in the middle of the plug.
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However I was able to get the GM part number of the one in the pictures and can order it. Double check but the number is 12551595 if anyone is interested in going that route for their second oil sending unit placement.
1. Tach - I feel like a fool. As soon as I went to 4cyl mode and no power input through resistors the tach worked fine.
2. Oil pressure - I bought an adapter and screwed the autometer sensor into it using a 90 degree bought from True value. It needed the 90 degree to keep from hitting the back of the intake.
3. Water temp - Bought the Equus 9848 from Oreiley Auto parts and the Autometer sensor screwed right into the passenger side head.
4. Oil Temp - I have the Autometer oil temp wired right to the PCM and it works fine.
Let me know if anyone has any questions about what I did. Thanks everyone for all the help!
Mike








