#3 FUSE ON V.S. KEEPS BLOWING, NO VOLTAGE TO COIL

My 2001 V.S. keeps blowing the 3rd fuse from the left (15amp). There doesn't appear to be any voltage to the coil and obviously none to distributor. The car was running perfect and just quit like it was turned off. It is getting fuel and I replaced the coil, installed a comp-u-fire ignition and replaced the dist cap and rotor as a result of the sudden shut down. The distributor is spinning, there is just no spark. The fuse appears to be servicing mostly black wires. The wiring diagram on this site doen't seem to be very similar to diagnose where the problem may be originating from. All of the wires into the back of the tachometer are tight and correctly placed and there is also no activity (no revs showing at cranking over engine)from the tachometer.
Is it likely that there is an internal problem in the tachometer that is creating an electrical short and therefore no current to the coil?

Any help/suggestions are welcome.

Thanks, Dan

Dan,
What I would do first is get a circut breaker rated close to what the #3 fuse is and connect it in place of where the fuse is. You can find one of these at any auto parts store for cheap and they are very handy for electrical diagnosis. This will help you because you won't have to keep replacing fuses during diagnosis and you will be able to hear the breaker click when the current is too great for the circut. From that point you can start un plugging things (tach, coil,ignition switch, flasher, etc) and when the breaker stops clicking, you will at least be closer to where your problem is. Only unplug one component at a time. Be sure the breaker is rated (amps) as close to the fuse rating as possible. All this is assuming that the fuse blows when the key is in the "on" position.
Mike

Dan,

Unplug the wire from the coil that sends the signal to the tach. If the car starts, it's the tach. If it doesn't, run a long wire from the positive battery terminal to the positive side of the coil, quickly start the car. If it starts, begin tracking the short with your gauge/tester. If it doesn't start, there are more complicated ignition problems ahead. Get a manual and diagram and go to work.

TC

Mike's idea of getting a circuit breaker at an auto parts store is a good one - keeps the frustration level down as you track this down. They are usually tab-mounted. If your fuse panel is tab-type, then you're all set. If it's the old VW cartridge-fuse style, then attach the tab-breaker with alligator clips.

I think we all suspect simply a chafed or shorting wire somewhere in your harness. As an alternative to pulling the tach lead from the coil, you might approach it from under the dash, too.

You said that "The fuse appears to be servicing mostly black wires", so disconnect all of those wires going ONLY TO THAT FUSE which is blowing, (which should now be replaced with that circuit breaker). You now have two ways to go. I would find a volt/ohm meter (VOM) and test each of those leads to find which one is a dead short before I re-attached any of them, but if you don't have a VOM, simply re-attach the wires one at a time, trying to start the car after each one is attached. This way, you'll see which wire is a short and blowing the fuse or breaker and can trace just that one down to see why it's shorting and correct it.

Bear in mind, you may still find that it's the tach - we're just approaching the problem from a different direction.

Sorry, i don't have a vs to compare it to.
But didn't someone find a shorted oil psi swt worked witht the coil.

sorry about that last post, what i meant was the other car trouble
listed, "the car that ran for 40 seconds" found that the oil
pressure switch was shorting the coil to ground.
don't know if this helps, good luck.

Dan,
Give Kirk a call, it may be something he has seen.
-=theron

ignition on wrong side of coil?

Did the fuse blow before changing ignition? ...

Thanks for all of the suggestions. The circuit breaker is an excellent idea. I believe I found the short, it seems that the wire in the steering column is shorting somewhere. I checked all of the ground wires/connections throughout the car and found them to be tight and in good condition. I crawled under the car and found the wire to the horn button to be slightly crimped in the slot of the opening of the steering column where it connects to the steering box. I did get the car running and drove it around town a few miles without any problem. However, this morning the tach and oil temp/pressure gauge went dead but the engine ran fine, the 4th fuse had blown. My next action will be to remove the horn wire and replace the entire wire. I'll post an update as soon as I have one. In the meantime, I still welcome any relevant suggestions or past experiences that would assist in diagnosing any this any further. I did call Kirk the other day and he was very sympathetic, and told me that if I was still having trouble to call him back and he would try and help however possible beyone his initial suggestions.

PROBLEM ELIMINATED! The bracket holding the tach in the dash was intermittently grounding on the bracket for the speedo. Thanks for all of feedback.

Glad you found the short, Dan.

Tracing electrical shorts can be a major PITA, especially in these cars where the electrical systems are (a.) mostly custom and (b.) often different from one another.