Mr.Gravyboat

I just picked up this 86 rx/7. It has a few problems the ones i'm focusing on now are the rev gauge not working, the sunroof (which i found a couple guides on here about) and the passenger headlight won't come on unless i turn on the highbeams. this is my first project car so i need all the help I can get, thanks in advance.

misterstyx69

iTrader: (142)

bad trailing coil..connections at trailing coil.OR bad trailing spark plugs or wire
The TACH gets it signal when the trailing plugs fire off,so if that "circuit" is not completed due to any of those factors it will not register RPM.

Burnt out LO beam on Passenger side.

Mr.Gravyboat

Thanks! I was hoping that it would be a burned out bulb and not a wiring issue but wasn't sure if it had two bulbs.

misterstyx69

iTrader: (142)

The headlamp connector is like a 3 prong plug.
the headlamp itself has 2 filaments.One for LO and one for HI.
A common wire is used to feed Both HI and lo (-)..but separate LO and separate HI + wires..(hence 3 wires to the headlamp)
it's common for the LO to burn out.It's used more than HI is.Right???
That is my guess at this time.
You can easily test this with another Headlamp..just replace and see if you get LO..if NOT then it may be a connector issue or something more delicate like wiring.
But My bet right now is a bad headlamp.

Mr.Gravyboat

yeah i'll have to get a headlamp. how would you check for the rpm gauge problems?

satch

iTrader: (1)

There are bullet connectors at each coil. They each are Black wires and connected to nothing. Jumper these two connectors to each other and see if the tach works properly. If they do then you know the tach itself is functional and thus your problem lies at the trailing coil.

Mr.Gravyboat

alright i'll try that out. thanks for all the help

Mr.Gravyboat

Ive been having trouble with finding the bullet connectors. I don't know if you were talking about one being at the trailing and one at the leading but heres what i've found.
that one is at the side of the trailing

and that one is at the leading coils

Mr.Gravyboat

are you saying the connector is bad? or that i've found the right connectors? haha sorry

satch

iTrader: (1)

The pic of the lead coil is definitely the bullet connector. If the pic of the trailing coil one comes from the same group of coil wires (trailing coil) then it is also the proper connector (it's a bit hard to see exactly where that connector is coming from while it is obvious from looking at the pic of the lead coil though).

Mr.Gravyboat

thanks i don't know what that other guy was talking about. So after i connected those two together i got nothing on the rev gauge. does that mean the gauge is bad?

misterstyx69

iTrader: (142)

I see the trailing coil is not attached to the car..am I seeing that correctly?

satch

iTrader: (1)

Could be the Y/L wire from the trailing coil is not connected.

J0SH

iTrader: (1)

Sounds like the trailing coil.

satch

iTrader: (1)

Just a thought, but do the other gauges work not including the speedometer? If they do then you need to do more diagnosing. Behind the gauge cluster are two round plugs. One has a Yellow/Blue wire. This is the same wire at the trailing coil check connector. W/the round plug housing the Y/L wire unplugged you can conduct a continuity test on this wire. W/the multimeter set to continuity you place one meter lead to the check connector wire and the other meter lead to the Y/L wire at the gauge cluster plug and it should ring out. If it doesn't then either there is a break in the wire or more likely the Y/L wires are not mated at connector FME-01.

Mr.Gravyboat

the trailing coils are just moved to the side for the picture everything was still hooked up. i did all the tests with it in the right place. the only two gauges that dont work are my tach and my temp gauge.

satch

iTrader: (1)

When you say hooked up do you mean bolted to the fender?

Mr.Gravyboat

i did it bolted in yes cause i thought that may be how its grounded.

Mr.Gravyboat

im pretty sure its the tach gauge itself i did the continuity test and it worked perfect. thanks for the help guys