Hello! Last year, I bought a '65 Fury as a 90% finished project. All the hard work had been done, and it had a super-nice paint job. Long story short, I got it on the road a few months ago with a fresh 440. It's a 4spd car (check out my avatar), and it runs like a scalded cat. Here's the problem - I installed an electronic Pro Comp II tach, exactly following the directions, and it worked just fine...for 4 rides. On the 5th ride, it froze at 3,000rpms and wouldn't move. I had the receipt, so I sent it in for warranty repair, and it got it back a week later. Reinstall. Same deal. Before I go further, a bit of history - Yes, I know that the bulkhead connectors on Mopars SUCK, and create problems because of corroded connections. Yes, I pulled mine apart and cleaned them. I'm also aware that the Amp gauge (installed and working) Mopars tend to stop working and create problems with the charging system. I've upgraded the car to the later model (square back 40A, I think) alternator, along with the electronic voltage regulator. While driving recently, the headlights started flickering, going SUPER bright for a second or two, then back to normal, which to me indicates an intermittent break in the connection between the alternator and the regulator (going full-field charge). Fast forward to last week. The tach has been repaired 3x, and yes, it just stopped working AGAIN. What's going on? Yes, I have an in-line prong type fuse (2A). I'd think that if a momentary interruption in the connection between the alternator and regulator sent a voltage spike to the tach, it would blow the fuse. Am I wrong? If anyone can help me out, I'd appreciate it. FWIW, I had an OT 68 Chrysler 300 that blew 9 sets of headlights until I just bypassed the Amp meter and ran a hot lead from the back of the alternator to the battery. Problem solved. Damn thing drove me nuts until I did several hours of research to figure it out. Chris
Well......... maybe switch to an automatic or retrace your steps, paying attention to grounds and relays. Couldn't hurt.
Yes, I'm afraid you are wrong. A fuse blows when the CURRENT going through it is too high (for a long enough time), it offers NO protection against over voltage at all. Electronics can be very sensitive to too high voltage, no matter how low the current is at the time.
G-son - Ok, so Amperage is a measure of current(?) vs. voltage?. Sorry if it's obvious, but I'm still building my electrical knowledge base. How can I protect against an over-voltage condition? Chris
Current, measured in amperes, is basically the flow of electrons. Compared to water, it would be gallons per minute running through a hose. Voltage is the "pressure" that makes the current flow, just like pressure makes water flow. And just like too high pressure might blow a hose, too high voltage might kill some sensitive electronics. The best protection against over voltage conditions would in my eyes be at the source - making sure that the regulator and alternator does exactly what they're supposed to do. This does indeed indicate overcharging at a much higher voltage than normal. I couldn't tell you exactly how it happens (other than some kind of regulating problem), but it's certainly enough to kill anything that hasn't been designed with a big enough margin for excess voltage.
I would also check your grounds, especially the engine to body. this can cause voltage spikes and also lead to fires.
are you using the blue mopar voltage reg if so there not really meant for street use go with a quality store brand or a nos mopar unit
Not a Mopar Guy, so just throwing this out there. Does pulley Diameter matter in relationship with Crank size Pulley?
Rick - I cleaned off the ground connections, and added additional ground leads from the battery to the frame and firewall, so I'm pretty sure I'm good there. Racer - I will check which one I have. I realize that I have to fix the problem, and I intend to, but as a stopgap measure, would an automotive surge protector protect the tach?? http://www.goodallmfg.com/product/antizap/
Not likely. It appears to be designed to handle the voltage spikes that can occur near welding, and that's more like radio interference than an overcharging generator forcing (depending on generator size) perhaps a kilowatt of raw power into the electrical system. I don't know exactly how that little gadget works, but I can't see it being large enough to be able to take alot of energy w/o overheating and being destroyed.
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