ok, the tach in my 85 S is not working. i installed the engine wednesday and got it running last night. i understand the tach runs off of the trailing ignition. the engine runs great and i have a good trailing ignition as far as i can tell! the tachometer illuminates fine. it doesn't jump or twitch, it does nothing. what are some tests i can do to figure out why the tach isnt working and what else should i look for before i replace the tach? i've already inspected the meter fuse and it was good. all other gauges work, with the exception of the fuel gauge but i know that its not tach related.

 

i thought of hooking up an aftermarket tach into the trailing ignition just to see if i'm getting a signal. what do you guys think about that, think it would work? i've got a sunpro tach laying around that i usually use to test while tuning that should work just fine.

 

before going through that trouble, try hooking the tach wire up to the leading ignition coil and see if that makes a difference

 

Yes It should work. Gotta a guy here w/ the same problem. He is also doing w/ an aftermarket tach.

 

i dont want to install teh aftermarket tach, i just want to use it for testing purposes. i'll try hooking into the leading ignition.

 

what kind of swap did you do did you do the 12a to 13b swap if you did make sure you hook up the old harness wires that went on the trailing coil hook those back up thats how i got mine to work when that car runs on ether

 

bugman, thank you for the advice! i got it fixed tonight, turned out that the tach itself was bad. i swapped in another tach from another cluster and everything is perfect!

 

where is the tach hookup to the trailing?

 

correct, to the trailing

 

It is a yellow (if i remember correctly) wire that attaches to the trailing coil, It's just one wire.

 

All my gauges went funky once too, thought I had a bad wire- turns out it was loose.

Glad to hear everything is good with my old driveway queen, now Dave!

 

I bet I ripped that sucker off and never looked back... I'll take a second look around there, but im not trippin' about it.

 

you should see this car!!! almost complete. i just installed a complete dual pipe RB exhaust, all poly bushings, EXTENSIVE rust repair, fixed the rust, painted and undercoated the underbody, new rear bearings and seals, complete new front brakes, alpine stereo with infinity speakers, new window seals, fixed the headlight, new radiator, 2GDLIDFIS, 2G fuse block, SS clutch hose, newly used 12A, complete GS upgrade to the interior, hatch strut seals, SS brake lines(should be arriving today from RB), rear deck rust fixed, painted and undercoated, all emissions removed, window regulators cleaned and re-greased, rear diff fluid replaced with a durablend, new oil cooler coolant hose, newer omp lines, accel coil, new NGK plugs and NGK wires, fresh oil and filter, fresh coolant, carb rebuild, every bolt that i have touched has been cleaned to bare metal with a wire wheel and greased with synthetic grease before being reinstalled. there are a few things that still need to be done. the windshield still needs replaced, the rockers still need new metal and the car needs a nice paint job. i would also like to replace the hatch seal and upgrade the carb to a weber with a RB intake manifold. the addition of an aluminum radiator with an electric fan will also be a nice touch.

 

Pics man! We demand pics! sounds like you are getting there..

 

pics tonight or tomorrow...i have to go to work until 11p tonight. just got my RB ss brake lines!!!

 

i cant seem to find that stupid wire... i have msd6al with 3 blasters...

 

what wire are you looking for?

 

i can start a new thread in the non tech section if you want. i have the pics to post in the morning!

 

Jesus.
Yeah, I want pics

 

ok, i'll start a new thread in the non tech section...

 

new thread is up: https://www.rx7club.com/1st-gen-general-discussion-207/my-85-s-restoration-pics-751475/

 

never mind. i am not thinking right. i know which one it is.