my tacometer in my 88 fc NA recently stoped working and i was reading around and have gathered that this could be because of bad coil grounding, how do i go about checking this grounding issue??? thanks

 

They ground by being bolted to the bracket which is then bolted to the fender. If the trailing coil doesn't work then the tach won't work. Make sure the trailing coil is working.

 

how do i check the traling coil?? im really not sure how and i would really like to know how to do this. thanks alot

 

One way is to remove a spark plug wire from the trailing coil and place the boot of the plug wire very close to the bore/tube it was removed from. Then you have someone try to start the car as you look for the existence of a spark. If you see spark then that particular coil is working. Also when you try to start the car the tach needle should bump a little although if you say it doesn't work then you might not see a bump in the needle.

 

i can replace the coil if its bad right??? and if so are they expensive, and exactly how do i go about replaceing the coil, ill try what you told me to try about testing the coils asap, thanks for the info i really appreciate it

 

If you needed a replacement, you could buy one from a fellow member via the "parts for sale section" on this site.

Check this link:

https://www.rx7club.com/search.php?searchid=8737040

 

Make sure the 4 pin connector which connects the trailing to the wiring harness is not damaged or loose. The tach signal is on the yellow/blue wire.

 

ok so i tested the trailing coils and both worked well, i seen spark on both so i think they are ok no bumb in the needle probably because the tac has quit working i really dont know where to go from here any ideas would be appreciated thanks

 

Have you checked the condition of the tach wire and connector?

 

yeah i checked that 4 prong connector and the blue/yellow wire connecting into it and it all was well no signs of damage or any thing i could notice??

 

What about the round connector which plugs into the back of the gauge cluster? The one on the right side of the cluster deals with the tach.

Also, read post #10 in the following link to test the tach.

https://www.rx7club.com/2nd-generation-specific-1986-1992-17/car-runs-fine-but-no-spark-trailing-coil-908471/

 

i read the link on how to test the tac and im kinda confused on what exactly he is talking about maybe a more in depth explanation or some pics would help me out, im not sure what the bullet connector's are more detail would be really appreciated, thanks alot

 

Just look by each coil and there will be a single wire which ends with a round connector. The connector looks like a hollowed bullet in some ways. It's easy to find.

 

i will look for those bullet connectors asap and what exactly does he meen by,make sure you disconnect any elect plugs to the TRAIL coil assy, thanks for your patience and thaks alot

 

There are two plugs connected to the trailing coil. One has two Black/Yellow wires and the other plug has four wires which are Blue/Red, Yellow/Blue, Blue/Yellow and Brown/Yellow wires. Disconnect these two plugs.

 

hey good news i did the test and my tac worked, but how do i get it working for good? where do i go from here??? thanks for all the help i really appreciate it

 

Focus on the plug that connects to the trailing coil that has four wires. Clean the plug itself (not the outside of the plug but the inside of it) and also at the point where it connects to the trailing coil as well. Use dielectric grease to help improve the connection. You've proved that the tach works so the problem lies within the Yellow/Blue wire. See if this helps.

 

i have worked on cleaning the plug and the tac has begun to work off and on im going to work on cleaning it out better and i got a question is it bad to clean the the spark plug wire where it connects to the bore tube "the inside of it" with lectra-motive electric parts cleaner?? i cleaned it out and used some dielectric grease on the spark plug ends, now my car is idling all funny i hope i didnt mess some thing up

 

Not familiar with the cleaner so I do not know. If you used it only on the trailing coil then you could disconnect the two plugs to it like you did when you tested the tach and start the car and see if it idles the same by relying only on the leading coil, and if it idles the same then you know you didn't damage the trailing coil by cleaning it.

 

Funny, could have sworn I gave the solution in post #7.

Dielectric grease shouldn't cause problems unless you packed the spark plug boot full. Just use contact cleaner to clean out the boots and connectors. When you put things back together, put a thin layer of dielectric grease on the inner part of the boots and connectors.

 

hah hah your right, so everything is idling fine now i just cant get that dang tac to keep working. earlier when i first put the dielectic grease on the plug it seemed to be working good, now its not working at all. i tried looking for the point where the plug connects to the coil and what i found didnt really seem like it needed cleaned but i cleaned it anyways, im just kinda stumped right now hah thanks for all the help guys and having patience with me i really appreciate it

 

One thing you could try is to repeat the tach test you did previously but with a twist. Instead of jumpering a wire from the leading coil bullet connector to the bullet connector of the trailing coil, try connecting the bullet connector of the leading coil to the Yellow/Blue wire from the four wire connector of the trailing coil while leaving the two wire trailing coil plug disconnected as well. What this should do is run the tach signal from the leading coil to the wire that should be doing that same function at the trailing coil. If the tach works properly then the problem lies within the trailing coil. If the tach doesn't work properly then the problem lies within the section of Yellow/Blue wire that connects to the trailing coil to where it taps into the Yellow/Blue wire that connects to the tach.

 

hey so i ran a wire from the leading coil bullet connector to the yellow/blue wire on the four wire connctor of the trailing coil and the tac worked fine, so that meens that the problem lies within the trailing coil right??? just thought i would post up what i had found out thanks for your help

 

Sounds about right. There is at least one board member who has had the same problem and he just used the method for testing the tach which I initially suggested to you and he kept the bullet connectors jumpered to each other to keep the tach working. I do not know if this is problematic over the long term or not but if it works then it works I guess. Just an idea.

 

if i dont want to leave the wire jumpered over what would you suggest i do to fix it without jumpering them?? i just want to try to get it working right without leaving a wire strung across, hah thanks for all the help