brianchevy

Dear friends,

I have done some searches and found that lots of you are trying to put aftermarket tachs in these third gen camaros. I didn't find alot of answers on my searches thru the archive, but, I was able to get thru it. SO, I've decided to post this quick

HOWTO INSTALL AN AFTERMARKET TACH IN A 1987 thirdGen in the hopes it will help some of you.

1) Disconnect battery
2) Remove Vanity plate over distributor
3) Find the external coil, it should have 2 connectors on it.
4) Remove BOTH connectors, don't worry they are keyed and only go on 1 way. (you have to pull a retainer to remove the clip)
5) Find the GRAY connector with the pink wire and the white wire
6) Clip the white wire. somewhere in the middle.
7) Reconnect the coil connectors BOTH OF THEM.
8) Reconnect the battery and start the car. You will notice that the old crusty stock tach NO LONGER WORKS BUT THE CAR RUNS.
COOL, eh?
9) If you have removed the airconditioning vents in the center dash, install the tach (mine is an Autometer Monster Tach with shift light). Run the wires down thru the dash to the firewall, find a hole up around the master brake cylinder.
10) Hook the RED WIRE to the IGN plug in the fuse panel, it will need a male connector on the end to plug it in.
11) Hook the Black wire to the ground (i used the bolt at the far left under side of the dash with a nice extra washer)
12) Run the green wire thru the firewall and up to the COIL. Be sure and protect it well (i used some 1/4 inch rubber tube to ensure it didn't rub on the firewall.)
13) Strip and attach this green wire to the STUB OF THE WHITE WIRE YOU CLIPPED IN STEP #6 ABOVE)
14) IF you have headlight / dash lights you may want to hook up the backlight by using the WHITE WIRE FROM THE TACH. (it may be powered by the RED WIRE as an option).

TESTING:
Get in the car and turn the igniton part of the way, DO NOT START THE CAR JUST YET.....

SEE IF THE TACH RESETS, if it does, you are OK. (RESET MEANS GOING TO ZERO). IF it doesn't, you want to STOP and double check steps 1-14 to be sure you did them right. If it reset,
Then you are free to start it up and take a spin around the block.

ENJOY, A TACH THAT ACTUALLY WORKS, instead of a stock one that is 500-1000 RPM OFF. Mine was WILDLY INACCURATE.

I can send you some pics of the install (or point you to my website if you need more details).

So, there it is, i did it and i contributed to the net knowledge so others can do it.

Oh yeah, there's a good link here
http://chevythunder.com/fuel%20inje...str.%20mods.htm

which has some pictures which might help you if you need.

Good luck, and enjoy.

Brian LaRose
87 IROC Z/28; 305 TPI, 5 Speed. SCCA - class ESP

Damon

That's good info. How did you determine the white wire was the tach signal wire off the coil? Shop manual or trial and error?

That's a good one to remember: white wire = tach signal wire. I'm gonna go see if that works on my 91 Balzer (different engine, very similar ignition system).

Damon

Yeah, same on my 4.3L Blazer. Should note, however, that there are pink and white wires on BOTH coil connectors. The gray connector has larger gague wires and runs into the wiring harness. The other connector has smaller gague wires (still pink and white, though) and runs to the distributor.

Don't mix them up- I suspect cutting any wire that goes into the distributor would cause the ignition not to work at all.

86 redbird

Did you both have the external coil. I have a full size 87 GMC TBI. I just wonder which wire to cut?

transxtreme

Wow, i wish i could get a reply like that every time i post.

Dave89IROC

is it external coil, or internal?

if external, this will work, in internal, look on the top of the distributor cap, top of the wires going in, it will be labeled tach and batt, batt will have a large gauge wire going in, and you want to connect to tach

brianchevy

I should have put it in my TODO list, I had an external coil. Obviously, if you have the internal coil option on a TBI car or otherwise, you'll have to handle things differently.

TPI cars are good for some things, eh?

Brian

#18 ESP, Atlanta SCCA

http://www.bowtieracing.org