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73-87 Chevy _ GMC Trucks => Projects Posts (NOT VEHICLES) => Topic started by: modular93fox on March 22, 2011, 10:15:05 pm

Title: My tach upgrade... in the works
Post by: modular93fox on March 22, 2011, 10:15:05 pm
Been wanting to get a new dash pad and with that means I need to remove the tach thats mounted through the dash pad.. so I found a tach out of a Mecury Cougar with the 4.6 v8.... mint cluster that I took apart to get the tach out... this is what I ended up with...

(http://img819.imageshack.us/img819/1240/tachretrofit.jpg)

Before I took the needle off of the tach, I used some equipment at work that can send a specified voltage at a specififed frequency so I was able to map out various RPM points. After it was mounted, I set the needle back to the OE position.

All I have left to do is scope out the LS tach output and get it to match up with the Mercury tach... and then install in the truck :)
clint
Title: Re: My tach upgrade... in the works
Post by: bake74 on March 22, 2011, 11:01:16 pm
     Is the blank spot in the bottom for a fuel gauge ?
Title: Re: My tach upgrade... in the works
Post by: beastie_3 on March 23, 2011, 12:19:38 pm
its probably for warning lights
Title: Re: My tach upgrade... in the works
Post by: 1979C20 on March 23, 2011, 12:31:56 pm
Its probably like on our trucks with the Brake and Seatbelt indicators maybe?
Title: Re: My tach upgrade... in the works
Post by: modular93fox on March 23, 2011, 08:09:45 pm
yeah, there are some factory 87 warning lights there... seat belt and something else. I drilled out the rivets on the fuel gauge to remove the gauge part, and likewise to a spare oil psi gauge... just found some tiny screws, and installed the fuel gauge to that. I rubbed off the oil symbol and re installed the needle. Once i get the tach operational, i will put the new fuel gauge where the clock would go.
clint
Title: Re: My tach upgrade... in the works
Post by: modular93fox on March 26, 2011, 09:45:56 pm
tuned the tach output signal to 4, which is 6 cylinder mode due to the way the tach is currently wired. Read pretty accuratly, but has a dead zone like spot betweeen 1100-1300... no biggie as it reads almost exactly what HPtuners says after that. Good enough for now.