tachometer problem?
I just picked up an 83 GS (I think it's a GS... Sunroof, A/C 5-spd, pwr mirrors, but no pwr locks, windows, etc.)
Anyway, my tachometer didn't work. It worked for like a day after I changed the plugs, wires, rotor, cap and filters, but stopped again. Does anyone know where the sending unit is located and where the cabling goes? Or has anyone else had this problem? Any ideas on how to fix it? Thanks! I'm restoring this car to as close to original as I can. |
silly question, but did you remember to hook everything up the same on the coils.. the tac reads off of the trailing coil, so check those leads..
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I hooked up the wires the same as I found them...
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check and clean all the trailing coil wires. if that doesn't help test the the trailing ignitor(they are those little boxes mounted on the dist). how to do so is outlined in the Haynes manual. i think it's the one under the alt.
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I hooked up the wires the same as I found them... |
or make sure the cables behind the tach didn't come loose. it's happened to me once.
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not knowing if you are new to the world of rotorys,
but there are leading (L) and trailing (T) coils,and plugs. if the car has drum brakes on the back then your GS. disc brakes would be GSL,the wires can sometimes become brittle over the years, if you plan on keeping the car,,a book will help,,and welcome to the forum. there are some very nice and helpful people here. restore that puppy,.,..,. |
Those older tachs on the 83's are prone to acting up. I'm not sure at to how to fix them - maybe replace the connection or the cluster.
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tachometer problems continued
Ok... so I replaced both the ignition coils cause I thought it was a bad connection, and the tach STILL isn't working. I am on to replace the igniters next since I have two that I can replace them with, but if one was bad, wouldn't the car have trouble starting? The engine is running very well right now. BTW, does anyone know which coil is supposed to be the trailing coil? Right now it is the one closer to the front of the car, and the leading coil is the one closer to the windshield. Does it matter? And just to make sure my spark wires are connected correctly, as you look at the spark plugs from the drivers' side, top left is T1, top right is T2, bottom left is L1, and bottom right is L2. Just want to make sure I have the wires going to the right places.
Now back to the tach... it was working intermittenly for a little while, and now hasn't worked at all for a few weeks. I think maybe it might be a loose electrical connection, but even after moving all the wires i could find in the engine compartment, I couldn't even get the tach to budge. The long and short: If you have any suggestions, I am absolutely in need... Thanks!:confused: |
BTW, does anyone know which coil is supposed to be the trailing coil? Right now it is the one closer to the front of the car, and the leading coil is the one closer to the windshield. Does it matter? I scanned a picture out of the book but I can't get it to upload. If you want to check it out so you can see where the pin is for the tach (pin J) and see if it is tightly connected I can email it to you. The book tells you how to remove the circuit. Check a junk yard and see if you can get another circuit for a few bucks. After market tachs are nice, but expensive. Welcome to the forum and keep the questions coming... |
project84.. it does not matter wich coil is the trailing and which the leading (both coils are the same).. all that matters is that you have everything correct going from the dist cap to the plugs.
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huh, learn something ever day.
thanks |
BTW, does anyone know which coil is supposed to be the trailing coil? Right now it is the one closer to the front of the car, and the leading coil is the one closer to the windshield. Does it matter? And just to make sure my spark wires are connected correctly, as you look at the spark plugs from the drivers' side, top left is T1, top right is T2, bottom left is L1, and bottom right is L2. Just want to make sure I have the wires going to the right places. ~T.J. |
i thought that the wires going to the coils were just for power. (one ground, one power, and one tac). i figured that the coils are always firing, and it is the dist rotor and cap that decide when the coil actually connects to the plugs.
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project84, the 79's are the only ones with thermal nuclear reactors. everyone else got cats, meow. the reason you are talking about is also why the 79's read rpms off of the leading coil.
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Originally posted by riffraff i thought that the wires going to the coils were just for power. (one ground, one power, and one tac). i figured that the coils are always firing, and it is the dist rotor and cap that decide when the coil actually connects to the plugs. |
Look at the wiring for the coils themselves (power to the coils) One coil should have an extra wire going to it (count them). That extra wire is the signal to the tach. Check and make sure it's connected and not corroded. If you have the same amount of wires (power wires) to the coils then you have a problem. If not my best guess would be the trailing ignitor.
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the 79's are the only ones with thermal nuclear reactors But the haynes book, (blue cover 79-85 All models RX-7) don't say its for specific year or models. I think everyone should get headers, high flow mufflers, ditch the air pump, and get an electric water pump and electric fan. Thats what I plan to do.:smoker: |
Originally posted by jeremy the 79's are the only ones with thermal nuclear reactors BZZZ WRONG.......... 80 has thermal reactors too.......:D |
Ok, someone put up a questionaire asking who has the thermal nuclear reactor and who doesn't.
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Originally posted by jeremy the coils have "continual" juice being fed to them. basically big capacitors. they constantly feed the dizzy. as the dizzy passes one of the metal prongs in the cap, it arcs the power to the post, down the wire, and sparks across the plug. now the coil has just let the power go so it will automatically juice back up before the dizzy gets to the next post. as you can imagine this happens very quickly. Inside the coil there's a primary winding and a secondary winding. Current flows through the positive terminal, through the primary winding, out through the negative terminal and finally to ground via the the ignitor. This current flowing through the winding causes a strong magnetic field to build up inside the coil. Now, when the lobe on the dizzy shaft passes the electronic pickup it triggers the ignitor into switching off the primary circuit. This causes the magnetic field inside the coil to colapse rapidly which then induces a voltage into the secondary winding. Because the secondary winding has a far greater number of turns the voltage induced is a lot higher. The secondary voltage then makes its way out through the main post of the coil, through the dizzy cap to the spark plug and you know the rest. Thank you for attending REVHED's ignition 101. :) |
Thanks all. It seems all the connections in the engine compartment are in order, and I even changed the igniters. (I guess they didn't need to be changed) My next step is to pull apart the gauge cluster and make sure that all the connections are properly connected. If that still doesn't work, I'll try a new gauge cluster, and if it still doesn't work , I suppose that means there is a disconnected wire somewhere in the main harness that will cost WAY too much money to search out. I would be better off buying another 7.
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