I've always been pretty good at wiring and solving wiring issues but this is causing me to lose what little hair I have left! Hope someone here can tell me what I'm missing! Working on a 64 Falcon Ranchero. We put a new Rebal harness in it doing the complete rebuild and everything was working fine except occasionally the starter would stay engaged. We replaced the starter, no help so we replaced the starter solenoid even though it was new. Seemed to cure the problem untill a couple weeks ago. Christmas eve the car wouldn't start, finally determined no power to the coil, hot wired it and it started fine but again the starter stayed engaged. Bang the soleniod and starter stopped and got the car here to the shop. Ordered and replaced the iginition switch, no help. Replaced the solenoid again, no change. Right now if I try starting it with the key it will crank but won't start even though it does show power to the coil, and the starter will stay engaged till you bang the solenoid top with a hammer. If I run a jumper to the coil from the battery and jump the solenoid car fires right up and starter dissengages fine. Tells me something is wrong in the ignition circut but with all new parts any ideas what I should check?
Sounds like you have a feedback problem. Are the wires hooked up to the right terminals on the solenoid? i would get the wiring diagram out and trace the wires and make sure everything is right. If you can byp*** the ignition switch and it does not stay engaged i would think something is off in that side of it.
New clue. I just put a meter on the coil and I'm getting less then 6 volts at the coil. No ballest resistor so what would cause a 6 volt drop thru the switch? MSD distibutor and coil if it matters.
I was thinking feedback too. I didn't wire the car myself so checking the wires were hooked up right was the first thing I checked. I just checked at the ignition switch, starter solenoid and coil.
The stock harness uses a resistor wire. I had to replace it when i switched over to electronic distributor. Maybe the new harness is set up the same way?
Good grounds. No resistor wire but there if a fusible link. More checking and my voltage drop is thru it. Could the fusible link be acting like a resistor?
By "solenoid", do you mean the high-current relay that's usually mounted on the fender well, or the electro-mechaical device on the starter that shoves the pinion gear into the flywheel gear?
Were talking the relay on the fenderwell (Ford). Think I might of figured it out. Started checking volts the the main wire, wasn't the fusible link. Not use to having anything in line with the main power wire to the switch but duhhh, this one has an amp meter. Back side of the amp meter is smoked. Owner now tells me, yeah one night everything flashed off and smoke came out behind the dash, but then it all came back on and kept driving it. Still don't have 12 volts to the amp gauge. Tommorrow I'll start chasing the wire back to the battery from the gauge and I bet I find some damage, not enough for an open circut or a dead short but enough to create resistance and a voltage drop. I bet trying to run a 12 volt car on less then 6 volts creates all types of wierd syptoms!
Fixed it! Turns out it was the amp gauge, it was fried inside. Not enough to open the circut or cause a dead short (lucky for us) but to work as a voltage reducer I guess. First time for everything, never had ran into that before. Byp***ed it and everything works as it should. Time to put a voltmeter in.
Sounds like either loose connection at or in the ammeter or it was underrated. Internally they are just a very low Resistance circuit intended to carry the rated amps of the meter. The low resistance (shunt) creates a small proportional voltage drop that drives the meter movement. The big drawback to automotive ammeters is the internal shunt which requires all of the current in the system to p*** through it so big wires under the dash. The meter of the ammeter is nothing more than a voltmeter reading the drop accros the shunt. If you could make the shunt external it could go in the engine compartment and just have small voltmeter size wiring to the meter. I personally prefer an ammeter except for the big wiring. A voltmeter can indicate volts but there may be no current flow.
Good thing the PO gave you a heads up on the ammeter issue. I prefer a volt meter myself, win, win! Regardless, you would have figured it out soon enough. Bob
Glad you found it. I yanked all the amp gauges outta my stuff for that reason. If they go bad you'll lose all power, some power or none at all and still have gemlins. Smoked one in my 65 f100 while in college, didn't know it and drove 40 miles until the lights quit and truck cut off. Alternator was charging but smoked amp gauge blocked it so I killed the battery. I run volt meters now.
Makes sense, the severe case of "Moxie Deficiency Anemia" caused the solenoid to chatter and weld the contacts together.
grrrrrrrrrrr, ammeters! Switch to a voltmeter, and eliminate everything having to route thru the ammeter. With all the accessories we have these days,..the ammeters can be a bottleneck. 4TTRUK
No worries, amp gauge is going in the trash and volt meter going in. Funny what other "clues" come out after the fact, stereo was acting up, fuel, temp gauge reading funny, ect. + side I've learned a little more, never delt with voltage drop before.
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