New tach problems

[ChevyC102007]

I bought a Sunpro SuperTach II from Summit and it got here Thursday (ordered it on Saturday) Anyways figuring that since I had this weekend off work Id go out and install it on the truck.

After alot of cussing (wasnt the tach it wa a couple of my ignition connection came apart) I got the dang thing in about 45 minutes ago. I fired up the truck expecting to see the needle hovering at around 600 rpms at idle......................nothing, lose ground. Shut the truck off and grounded it to another spot. Started it back up....it works............wait a second...........the needle went BACKWARDS as my RPM's increased. WTF!?!?!

I sent Summit an email asking what the problem could be but it might be Monday or Tuesday before I hear anything back Im hoping someone on here has had the same problem or has an idea what it could be.

Before I forget the truck has a HEI ignition on it that was installed by the previous owner (with my luck the dumb things about to go bye bye on me).

Thanks......this just puts the cherry on a screwed up day

[Huck]

Sounds like you have connections reversed. One goes to the "tach" pole on your HEI distributor, another goes to 12V fused from your fuse block ignition, another goes to ground and another goes to lights. If connected correctly, it should work right so double check. By the way, the tach connection on the HEI should be the negative side of the coil!! Huck

[corn]

black-ground
red-fused ign post on fusebox
green-tach post on dist
white-lights post on fuse box

[ChevyC102007]

yep, yep and yep. All those connections are in the right places I hooked everything up except the light. Im gonna go out again today and double check.

I still have the original cover on the coil in the HEI that says "Tach, Bat" .

[ChevyC102007]

Ok went out and checked my connections...............hooked it to a fused power wire as per the instructions that is only on when the key is (Hooked it the fused power wire going to the distributor) nothing, now it wont even register.

At this point nothing would surprise me about anything concerning the wiring on my truck considering that the PO hacked it up. At this point I hav no dash lights (even with a new light switch) my new tach aint working and the amp meter shows just abit above the middle (internally regulated alternator and adapter kit from LMC).


I love my truck but right now when it comes to my wiring I give up.............

[ChevyC102007]

Alright.......I aint gave up yet. The tach is mounted in the truck just need to try and get it to work. Im gonna see if I can find some fuse taps and run the power and lighting wire to the gauge and interior light fuse's on the block and tap it in there..........might work.

Summit replied to my email and after explaining what was what as for the wiring they told me there was something wrong with the tachs wiring ( not how I had it hooked up) and gave me a pdf. link to the EXACT same instructions that came with the dang thing.


Wish me luck