Is my tach ruined? - Team Camaro Tech
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post #1 of 16 (permalink) Old Oct 6th, 07, 07:56 PM Thread Starter
 
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Is my tach ruined?

I started my 69 Camaro yestarday for the first time. It has a 396 with hei conversion and factory (OER) tach. When I started the engine the tach needle went up half way then back to zero. The main fuse (next to junction on radiator support behind battery) kept blowing everytime the car started. I replaced the fuse and disconnected the alternator. The fuse did not blow this time. I had the alternator rebuilt several years ago and I think I had the guy at the shop make it into a one wire alternator. I wired the alternator as a three wire when I hooked it up (not remembering I had it built as a one wire). Could this have caused any problems? Everything electrical works on the car except the tach. I have checked the wiring and it appears to be wired correct. The tach worked monentarily then stopped. I started the engine today with a new fuse and the wires disconnected at the alternator. The tach still doesn't work. Any suggestions would be greatly appreciated.
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post #2 of 16 (permalink) Old Oct 6th, 07, 08:08 PM
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Charlie
 
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Re: Is my tach ruined?

Where do you have the signal wire for the tach ran to? On my HEI, the cap actually had a terminal for connecting the tach signal wire. It was the negative side of the coil.

Charlie Knudsen 67 Camaro RS/SS 350 TKO 600, 4.10's, AFR 195 Street Heads, Comp 270H, Rhoads Lifters, Crane Ignition, Pertronix Dizzy, Performer RPM Q-Jet, Heavily Modified Q-Jet, Hooker Comp Headers, MagnaFlow 2 1/2", 144 Decibles(Alpine CDA-7998 Head Unit, RF X7 and RF 750X Amps, MB Quart Mid's & High's, Kicker L7 12" Solo Barics)
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post #3 of 16 (permalink) Old Oct 6th, 07, 08:13 PM Thread Starter
 
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Re: Is my tach ruined?

Mine is the same. I went to a wrecking yard and got the correct terminal for the wire.
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post #4 of 16 (permalink) Old Oct 6th, 07, 08:50 PM
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Charlie
 
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Re: Is my tach ruined?

Do you have the signal wire run to that terminal on the distributor?

Charlie Knudsen 67 Camaro RS/SS 350 TKO 600, 4.10's, AFR 195 Street Heads, Comp 270H, Rhoads Lifters, Crane Ignition, Pertronix Dizzy, Performer RPM Q-Jet, Heavily Modified Q-Jet, Hooker Comp Headers, MagnaFlow 2 1/2", 144 Decibles(Alpine CDA-7998 Head Unit, RF X7 and RF 750X Amps, MB Quart Mid's & High's, Kicker L7 12" Solo Barics)
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post #5 of 16 (permalink) Old Oct 7th, 07, 03:37 PM Thread Starter
 
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Re: Is my tach ruined?

I have the signal wire plued into the terminal on the HEI cap marked "tach". I'm wondering if the incorrect hookup on the alternator caused damage to the tach. It is a new OER tach, but I purchased it a few months ago. I guess it could be a faulty unit.
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post #6 of 16 (permalink) Old Oct 7th, 07, 07:37 PM
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Charlie
 
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Re: Is my tach ruined?

First things first, IMO I would shy away from running a one wire alternator. One wire alternators do not charge until they reach a certain rpm(usually 1000 give or take) and they do not charge at idle. So, if you have any extra electronics, it is going to put a serious strain on the system.

Second, tachometers as far as I know are not connected to the alternator. At least my aftermarket isn't. It has a power, ground, illumination, and rpm signal. You said it is an OER, you may be able to test it by running the wire directly to their respective destinations. What I mean is, do not use the factory wiring, it may have a problem with the OEM wiring. Run a power wire, a ground, you shouldn't have to worry about the illumination, and run a signal wire to the distributor. That will tell you if it is a problem with the wiring.

Charlie Knudsen 67 Camaro RS/SS 350 TKO 600, 4.10's, AFR 195 Street Heads, Comp 270H, Rhoads Lifters, Crane Ignition, Pertronix Dizzy, Performer RPM Q-Jet, Heavily Modified Q-Jet, Hooker Comp Headers, MagnaFlow 2 1/2", 144 Decibles(Alpine CDA-7998 Head Unit, RF X7 and RF 750X Amps, MB Quart Mid's & High's, Kicker L7 12" Solo Barics)
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post #7 of 16 (permalink) Old Oct 8th, 07, 06:41 PM Thread Starter
 
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Re: Is my tach ruined?

Thanks Charlie, I am taking my alternator back to the rebuild shop tomorrow. I thought I wanted a one wire when I had it rebuild a year ago. After doing some research, I decided to go with a 3 wire. I just installed the alternator the other day and started the engine for the first time. The alternator I have was originally a three wire, so I thought it would work as a 1 or 3 wire. I was wrong! After I get the alternator wired for 3 wire hookup, I'll try what you said with the tach. Sounds like a good idea. At least I'll know its not the wiring if it still doesn't work.
Rick
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post #8 of 16 (permalink) Old Oct 9th, 07, 06:29 AM
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Charlie
 
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Re: Is my tach ruined?

Good luck and post back with the results.

Charlie Knudsen 67 Camaro RS/SS 350 TKO 600, 4.10's, AFR 195 Street Heads, Comp 270H, Rhoads Lifters, Crane Ignition, Pertronix Dizzy, Performer RPM Q-Jet, Heavily Modified Q-Jet, Hooker Comp Headers, MagnaFlow 2 1/2", 144 Decibles(Alpine CDA-7998 Head Unit, RF X7 and RF 750X Amps, MB Quart Mid's & High's, Kicker L7 12" Solo Barics)
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post #9 of 16 (permalink) Old Oct 12th, 07, 12:59 PM Thread Starter
 
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Re: Is my tach ruined?

Okay......I got the alternator problem fixed the other day, so I decided to run all new wires to the tach. (Ground, -coil from HEI, and a power source from fuse panel). I started the engine and the needle still doesn't move on the tach. I was able to run the new wires without removing it form the dash. Does anyone know if I need a tach filter. I have read earlier posts that state you do, and some say you don't. Again this is an OER repro. tach for 69 Camaro. I'm gonna take the aftermarket tach out of my brother's Suzuki Samurai asap and hook it up to my existing wiring to see if it works or not. If it does, I know there is a problem with the tach or the OER tach needs the filter. I purchased the tach several months ago so the warranty is up. I hope it's something I'm over looking and not the tach. If it's the tach, I'm out $200.00!
Any suggestions would be greatly appreciated.
Rick
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post #10 of 16 (permalink) Old Oct 12th, 07, 02:12 PM Thread Starter
 
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Re: Is my tach ruined?

Well I tried the tach off my brother's Samurai and it doesn't work right either. It worked briefly, then went to zero. I turned off the engine and tried it again. The needle fluctuated from 0 to 4000 rpm then went back to zero again. I wired his tach inside the engine compartment to simplify things. One wire to the "tach" plug in on the HEI cap, one to ground and one to +. I'm thinking the problem has to be in the distributor. Any suggestions?
Thanks
Rick
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post #11 of 16 (permalink) Old Oct 13th, 07, 12:18 AM
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Re: Is my tach ruined?

Quote:
Originally Posted by refspd View Post
Well I tried the tach off my brother's Samurai and it doesn't work right either. It worked briefly, then went to zero. I turned off the engine and tried it again. The needle fluctuated from 0 to 4000 rpm then went back to zero again. I wired his tach inside the engine compartment to simplify things. One wire to the "tach" plug in on the HEI cap, one to ground and one to +. I'm thinking the problem has to be in the distributor. Any suggestions?
Thanks
Rick
Check all of your connections and solder them to be sure. If you are intermitatly losing power, ground or signal, no tach will work correctly.

Greg U

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post #12 of 16 (permalink) Old Oct 13th, 07, 10:46 AM
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Chuck
 
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Thumbs up Re: Is my tach ruined?

Quote:
Originally Posted by refspd View Post
Mine is the same. I went to a wrecking yard and got the correct terminal for the wire.
Sounds like a bad connection. So, you cut off a terminal at the bone yard and spliced it to the wire that is the signal wire for your tach? Try running a new wire with a normal female spade connector on the dist. end. It will fit onto the ternminal, but just won't lock on to the tab on the cap. It won't fall off if you have a good tight connection at the terminal. Did it like that on my daily driver and it has stayed on for 10 yrs.
LOL
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post #13 of 16 (permalink) Old Oct 13th, 07, 07:10 PM Thread Starter
 
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Re: Is my tach ruined?

Thanks guys, here is the latest. I took the plastic cap off the coil on the HEI yestarday and found that the yellow wire running from the coil to the neg (tach) terminal was pinched between the lid and the cap. I removed the coil and put in another one I had in my shop. I thought for sure this was the problem. Hooked everything back up and the tach still doesn't work. I didn't try the tach from my brother's Samurai because I already put it back in his rig and it was getting late. All new wires and terminals, but I didn't solder anything together. The tach harness is new and all the fittings are tight on the connectors. If you guys think the solder will help I can do that also. Is there anything in the distributor that could cause this problem? I'm just about ready to order a new tachometer and try it. All help is really appreciated!
Rick
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post #14 of 16 (permalink) Old Oct 23rd, 07, 01:59 PM
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J.A.
 
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Re: Is my tach ruined?

did you figure this out?
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post #15 of 16 (permalink) Old Oct 23rd, 07, 06:55 PM Thread Starter
 
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Re: Is my tach ruined?

I pulled the HEI out of the 56 Chevy pickup and dropped it in the Camaro. I then bought a $29.00 tach from the parts store and fired it up. Plugged the new tach into my existing wires under the dash and it worked like a charm. When I removed the OER tach I could see that it had a black burned spot on the circuit board and it smelt fried. Called Firewheel Classics where I bought it and they said they would replace. What a great company! The warranty expired a long time ago but they were understanding about how long it can take to build a car. I'm still not sure what the deal is with the distributor because I even switched out the control module before swapping out the distributors. Thanks for asking J.A
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