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1987_345 · 05-11-2020, 02:14 PM

And so my gauge issues continue.... Does anybody know if aftermarket spark plug wires are incompatible with the tach pickup coil? It mostly reads "0", but sometimes bounces a little. I'm not even really sure when it stopped functioning or how to test it. Any ideas? Kenneth

Rich W · 05-11-2020, 03:49 PM

Left field comment - On my outboard the tach quit. Repair shop said that is usually an indicator of voltage regulator failure. Replaced the voltage regulator and tach is back. I have no idea if this would translate to your application, but it's a thought.

jhenry · 05-11-2020, 05:05 PM

Ken I have a tach as well as the speedo. Jonathan

1987_345 · 05-11-2020, 06:26 PM

I hadn't thought of that Rich. Electronics is my weakness!!. I believe the voltage regulator on my coach is built in the alternator. I haven't had any issues there yet so I'm guessing that's not the problem. Were you able to notice any warning signs of your failure on your amp gauge?

Kenneth

Rich W · 05-12-2020, 08:07 AM

Quote:

Originally Posted by 1987_345

I hadn't thought of that Rich. Electronics is my weakness!!. I believe the voltage regulator on my coach is built in the alternator. I haven't had any issues there yet so I'm guessing that's not the problem. Were you able to notice any warning signs of your failure on your amp gauge?

Kenneth

I don't have an amp gauge but my voltage was spiking at around 19 volts, another sign of a bad regulator. One of the wires on the regulator had a crispy connector. Again, this is an outboard motor.

If you want you can take your alternator to a parts shop like Advance Auto etc. and they can put it on a machine to test it.

I did find that on cars the tach gets its signal from the ECU (electronic control unit) or the ignition coil pack ground circuit. They said to check all the connections for corrosion. Maybe these images can help you.

1987_345 · 05-12-2020, 10:13 AM

Thank-you so much Rich for the illustrations. That is most helpful

davejay · 06-01-2020, 08:41 AM

Hey
When we bought coach 5420 miles on a. 85 325
In going through the electronics I noticed a wire coming off the tach along with the original wire
So I cut it no tach reconnected it tach works
Maybe in the wire harness from gage to distributor there's a break run a separate power lead from tach to distributor it might that simple DJ

1987_345 · 06-13-2020, 01:40 PM

Still working on the tachometer issue. I have a question I hope someone can answer for me as I try to eliminate the possible causes of my problem. Does anyone know where the tach gets its signal from? Is it from the tach port on the distributor or is it that electrified looking ring that goes around the front left spark plug wire? Anybody?

Smartstream · 06-14-2020, 12:06 AM

I can't speak for the gas units but both of my diesels drive the tach from a terminal on the alternator. It was a simple add on connection when I had the last alternator built.

I also ran across a programable Teleflex tach. They had two versions, one ran off a low frequency of pulses and the other a much higher frequency. There was about a dozen dip switches on the back for set up. Good luck

Air345Fly · 06-14-2020, 05:10 AM

The thing that clips around the spark plug wire is for the cruse control.
The tach is driven from the distributor.

davejay · 06-14-2020, 05:35 AM

Hey
Your tach signal comes off the tach. The coil is built into the distributor. Maybe you got a problem within the dist. I haven t looked in a while but those contact leads that the tach connector plugs into at the dist are also connected to a wire. Maybe the one for the tach has broke loose. Worth a look. It may be that simple. Dj

1987_345 · 06-23-2020, 05:31 PM

Quote:

Originally Posted by Smartstream

I can't speak for the gas units but both of my diesels drive the tach from a terminal on the alternator. It was a simple add on connection when I had the last alternator built.

I also ran across a programable Teleflex tach. They had two versions, one ran off a low frequency of pulses and the other a much higher frequency. There was about a dozen dip switches on the back for set up. Good luck

Thanks Dan. Mine must be different. It doesn't have any dip switches

1987_345 · 06-23-2020, 05:32 PM

Quote:

Originally Posted by Air345Fly

The thing that clips around the spark plug wire is for the cruse control.
The tach is driven from the distributor.

Thank-you Air345fly!!!!! That helps me alot

1987_345 · 06-23-2020, 05:34 PM

Quote:

Originally Posted by davejay

Hey
Your tach signal comes off the tach. The coil is built into the distributor. Maybe you got a problem within the dist. I haven t looked in a while but those contact leads that the tach connector plugs into at the dist are also connected to a wire. Maybe the one for the tach has broke loose. Worth a look. It may be that simple. Dj

Thank-you Davejay. That's what I'm hoping for. Something simple!!