Hey guys i just picked up my new toy, its a 1985, GS. The Tach is not working on it though. All of the other guages work fine, including the voltage meter. I checked the wireing up front at the leading coils and everything seems to be in place. I took out the guage cluster today to make sure everything was plugged in a looking normal. What could possibly be my culprit? Also on a side note, the lighting on the guage cluster doesnt work, but i read it is probably my dimmer switch? Thanks for all your help guys.

 

Most of the time its the trailing ignitor.

 

trailing ignitor not getting good enough ground, take it off clean the round metal holes on each corner of it, and put it back, make sure you use dy-electric grease. also, yes your dimmer switch is gone most likely. check under your shift boot for two wires (black and red i believe) they should NOT be plugged together, they're there if you have an automatic. then just by-pass the dimmer switch, very easy to figure out how to do. or replace with new.

 

Pics? Congrats on the new toy/daily driver.

If the trailing igniter is out, the fuel pump will soon follow and your new baby, without gas, will not run. I'd do the above but if the car's running great, might be something else.

You might want to check and be sure those two wires under the shifter boot aren't hooked up, like the Blackdeath says.

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hey guys thanks for the quick responces. I will check out the ignitor when i get home. Is there a way to tell which one is Trailing and which one is Leading? Right now the car runs really good actually, it has alot more pep than i thought the 12a would have (The only FB i had was a GSL-SE) And i will take pics when i can, Shes in pretty good shape for her age though. Im happy with it.

 

So where is this trailing ignitor you speak of. I would like to check mine. My tac will not work until the car warms up. I got no clue why, but I will continue to follow this thread.

 

trailing SHOULD be the one closest to the alternator (FB). leading is the one pointed towards the radiator.

just clean the grounds and reinstall with enough dielectric grease. hopefully this will fix your problem. in 84/85 models the gas pump is also connected to the trailing, so like ray said your pump might be next to go.

i don't know where the tach connects to the ignitor at, but you can clean your connections to eliminate the cheapest things first.

 

Anyone got a pic of the ignitor?

 

http://www.smbaker.com/rail/ignitor1.jpg

that's from the rear, its the quickest one i could find...just image search for a j109 ignitor.

 

The Tach gets its signal from the Yellow/green wire connected to the negative terminal of the trailing (front) coil. Make sure you have a good connection and that the wire harness leading to it has not been cut or damaged.

 

Are the front coils the two bell looking things attached to the drivers side fender? The wires from the Dist. go there?

I will clean my ignitors also.

Will it hurt to take them off and spray with the electronic spray cleaner, scuff them up and put them back on with the dielectric grease?

 

not at all...actually, that's kinda what i meant by cleaning up your connections.

 

hey guys sorry for my slow responces. So i havnt had a chance to clean the ignitor yet (church and work has kept me busy) but i did notice the the wireing harness has been cut into. I will investigate more throughoutly and let you guys know progress as soon as possible. Thanks for all of the help so far! i hope this is helping you out White81Z28

 

I cleaned mine today. I will find out tomorrow morning when I start it up. Might be like the other guy said, the gel in the needle just gets cold/heavy and stops it from going up. Did not mean to hijack your thread, sorry.

 

Well, it did not work this morning. It will work once it warms up though. Very strange, guess the guy was right. Ive cleaned all the connections on the ignitors and coils, including the ground. Oh Well.

 

ok so i finally cleaned both ignitors and i still have no tach. I think it must be the harness, somebody hacked into it. So what is my best plan of action now? if there is one thing i lack at in knowledge its electronics.

 

The yellow green wire connected to the negative terminal on the trailing coil travels into that harness a few inches and then splits. one yg wire goes to ignitor and the other goes to the tach. Either unwrap the tape on the harness until you find the problem or just add a new wire to the coil terminal. Find the yellow green wire in the harness near the firewall. Connect the other end of the new wire to the yellow green.

z28's problem is very common. My tach doesn't work at start up when it is below 40. After 5 min of running everything is fine.

 

ok so here is my progress.

After i took off both ignitors, cleaned them, and put them back on. I started up the car and it was idleing really rought. It sounded like a really slow bridgeport, lumpy (and still no tach signal). So i thought that maybe i had set the timing wrong so i took out the distributor and reset the timing, then it just didnt really want to start at all. It would kinda of kick over, and sound like it was only running on 1 rotor. So after checking everything out, a few of the connections on the rotor cap looked kind of corroded, so i bought a new cap, rotor, and spark plug wires just to be safe. Try to start it again and the same thing!

So now it has to be either the ignitors, or the coils. So i switched the ignitors around. Now i have a Tach signal! i can see it bumping when i am turning over the engine. But the car doesnt want to start. Switch them back around and the car will kind of kick, but i wont get any tach signal. Odly enough switching the coils seemed to get different responces too. COuld i have done something wrong when i cleaned the ignitor?

Oh and the wireing harness checked out!

 

Sounds like your trailing ignitor is bad. No tach signal and no trailing ignition and when you switched them the car wouldn't start because there was no leading ignition.

You usually don't need to remove the distributor to adjust timing. Be very sure it is in the right position.

 

yeah but i had to take the dist. out to get one of the ignitors off. So when i put it back in i had to set the initial timing (line up the mark on the pulley, ect ect.) nobody has an ignitor and there arent any FBs at the local junkyards. any suggestions?

 

Do they not make the ignitors anymore?

 

Swap the ignitors around. It sounds like when you reinstalled the ignitors, you put a good lead ignitor where the trail ignitor goes and vice versa. A bad lead ignitor will make the engine barely run worth a darn. A bad trail ignitor won't be missed except for lack of a tach signal.

 

Only correct for pre-84 models.

https://www.rx7club.com/showthread.p...uel+pump+relay

 

Also remember that your fuel pump wont run with a bad trailing ignitor, or wont run well. If cleaning the ignitor doesn't work, go hit up some junkyards for an old first gen ignitor. Have them test it first before you buy it, cause they love to blow out, and can be quite expensive. Another alternative is to wire up a GM HEI ignitor, they are about $20 at the parts store, ask for one for a '73 Chevy Nova V8. There's only four wires that need to be hooked up, and the ignitor can be mounted to your inner fender wall, it works great to dissipate the heat.

W - Connects to the positive lead at the distributor.
G - Connects to the negative lead at the distributor.
C - Connects to the negative side of the coil.
B - Connects to the positive side of the coil.



That should get you running, post back and let us know.