Mschafe

I was told by an RX7 Mechanic that the tach on an '83 doesn't usually work till the engine heats up. Is that true? Mine doesn't seem to be working, but I really haven't gone anywhere with it yet (no current tabs).


Thanks,
Matt

BadAssRX-7

dont go back to that guy, he sucks! the tach runs off the trailing ingtor. my l.e. didnt work so when i flew out to get it i brought another ing.

smnc

I agree, the mechaninc is a dumb-***. Heat has nothing to do with operation of an RX-7 tach.

Mschafe

I thought that sounded stupid. Well, if anyone knows how to fix it, that would be great.

Thanks,
Matt

moremazda

iTrader: (4)

1) I agree with every one here, that mechanic is a dumb ***
2) Your tach will either work or it won't. If it doesn't move with the engine RPM you have either no signal or no power. If you have those then it's broken time to vist the local junk yard. Get a Hayes or Chilton manual, they will have wiring diagrams and you will be able to locate and test the need wires.

Ryan

V8kilr

well it sounds like it could be two things

1-bad trailing coil.
no biggie go pick up some msd's

2-bad ignitor
biggie $500 from mazda trix.get them from a junk yard


your probably thinking well if my trailing coil or ignitor was bad wouldnt i notice?no you wouldnt.at least i didnt when i bought my first rx and one of my ignitors was bad.found out it went when i was hooking up a tach!

peejay

I think it's a problem in the tach or something.... 'cos if it was the trailing ignitor the fuel pump would also be not working... y'see, the computer (yes the carb cars had computers too!) gets the engine speed signal from the trailing ignitor. it uses it to help determine when to work various solenoids, and the computer also controls the tach and the fuel pump. that way if the engine stops running, like if you were in an accident, it cuts the fuel pump off so in case a fuel line was ruptured it doesn't hose gasoline everywhere.

Since your fuel pump apparently works, we can rule out the trailing ignitor. I know from experience that a 12A can idle for a good three-four minutes on just the fuel in the carb, with no fuel pump running, so if the tach takes less time than that to "kick in" then it could be the ignitor after all.

Mschafe

I found a thread on this exact problem... Their tach didn't work until the car warmed up... Here...


https://www.rx7club.com/forum/showth...&highlight=GSL


Matt