Tach quit and tilt and trim gauge quit.

[ryan_289]

Noticed two issues with my 98 Chaparral with a 4.3 Volvo penta today. First when I put it in the water I noticed the tilt gauge not working. It stay in the up position all the time. It was supposed to have been recently replaced when we bought it a couple of weeks ago. Are there things I can check to see what could have happened?

Second, I took off down the lake and noticed my tach started bouncing. A little bit later it just quit. Ive installed tachs on vehicles before, Are boat tachs the same way? Power wire and a wire running to the coil? If those connections are good is there any way to test the tach itself?

 

[ryan_289]

Re: Tach quit and tilt and trim gauge quit.

I found a test procedure for the trim sensor, does anyone have a diagram of how the tach is wired?

 

[Silvertip]

Re: Tach quit and tilt and trim gauge quit.

+12 volts on the "I" terminal comes from the "I" (ignition) terminal on the ignition switch. Ground is ground wherever you find it and the tach sense signal comes from the ignition system and connects to the "S" terminal. +12 volts and ground can be daisy chained from any other gauge. If all the other gauges work I'm guessing the sense "S" terminal signal is missing.

 

[ryan_289]

Re: Tach quit and tilt and trim gauge quit.

Will my multimeter pick up the signal at the S terminal when the engine is running? If so I can check for signal at the gauge, if im picking up signal the tach would be bad correct?

 

[Silvertip]

Re: Tach quit and tilt and trim gauge quit.

The tach signal is a modified AC pulse that your meter should pick up. Set it on the lowest AC volts range. Just because you have that signal does not mean the gauge is bad if it doesn't read anything. It still needs +12 volts and ground.

 

[ryan_289]

Re: Tach quit and tilt and trim gauge quit.

Does the tach wire run through the main engine harness plug? It came unplugged yesterday when I was removing the thermostat but im wondering if I bumped it loose the other day before these issues started.

 

[NYBo]

Re: Tach quit and tilt and trim gauge quit.

Does the tach wire run through the main engine harness plug?

From the factory, yes.

 

[ryan_289]

Re: Tach quit and tilt and trim gauge quit.

Well I figured out the trim gauge. Apparently it shares a fuse with the radio. I was installing a new cd player and wasnt getting power. I traced the wire back to an inline fuse under the dash. When I replaced the fuse the trim gauge also started working as well. Now the new problem. Everything works fine untill I turn the radio up loud. Then it pops the fuse. Im guessing the new cd player and new speaker pull more power than the original. Should I run a new dedicated wire to the stereo to pull some amps away from that wire? That still doesnt explain how the fuse popped originally but I had to cut some zip ties to get the fuse apart. It may have been the original fuse and it finally just gave out?

 

[ryan_289]

Re: Tach quit and tilt and trim gauge quit.

Update for anyone following.

The tach gauge must share that fuse as well. All works fine. I also ran a new dedicated wire for the stereo and that all works good too.

 

[NYBo]

Re: Tach quit and tilt and trim gauge quit.

Thanks for the update. Sharing circuits is usually a bad idea, as you've discovered.