Jester's Progress...
- Thread starter Jester
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thrashingcows
Drowning deep in my sea of loathing...so I'm
Just put some duct tape on and forgot about it....:wtf:
Jester
In through the Out Door, so She's
Well, 11 years later and I get a chance to update this thread. Took GoldMember for a drive today, and she ran beautifully for a car that sat for about 2 years with not much more than an oil change and some fresh gasoline.
On the way home, driving up a steep hill, around a rather tight right bend, I heard a not too loud BOOM!, and felt the car shake a bit, then continued up the hill like nothing happened. Felt exactly like the time my battery blew up, so I glanced at the volt gauge (around 14.5v), and figured I blew another battery. Pulled into the garage, popped the hood and found nothing wrong. crawled around the car, checked what I could and found nothing out of the ordinary.
Weird. I'll have to take it for another boogie tomorrow. Oh yeah, I converted the amp gauge to a voltmeter, and did some bypass soldering while the car was in storage. Actually destroyed 2 volt gauges and can't figure out why. I'm on the third gauge and it worked fine all day. Sunpro gauge and bosch gauge seems to fit in the factory space nicely. Positive lead goes to the fusebox and negative to a decent ground.
On the way home, driving up a steep hill, around a rather tight right bend, I heard a not too loud BOOM!, and felt the car shake a bit, then continued up the hill like nothing happened. Felt exactly like the time my battery blew up, so I glanced at the volt gauge (around 14.5v), and figured I blew another battery. Pulled into the garage, popped the hood and found nothing wrong. crawled around the car, checked what I could and found nothing out of the ordinary.
Weird. I'll have to take it for another boogie tomorrow. Oh yeah, I converted the amp gauge to a voltmeter, and did some bypass soldering while the car was in storage. Actually destroyed 2 volt gauges and can't figure out why. I'm on the third gauge and it worked fine all day. Sunpro gauge and bosch gauge seems to fit in the factory space nicely. Positive lead goes to the fusebox and negative to a decent ground.
Dr.Jass
Pastor of Muppets
That boom was probably the exhaust pressure releasing as the mouse nest, along with any residents thereof, were expelled at high speed out the tailpipe. If there was nothing physically wrong with the car afterward, it's the only thing that comes to mind immediately.
I'm not sure how one would blow up a voltmeter without spiking it. My suggestion would be to check your alternator field wiring very closely. Make sure there's nowhere it can ground (bare spots, cracked insulation, etc.). If it does ground, the alternator goes full field and will throw way too many volts at the system. The '81 Imperial I had in the '90s had that issue, and it was near 18V at idle, 20V plus at cruise.
I'm not sure how one would blow up a voltmeter without spiking it. My suggestion would be to check your alternator field wiring very closely. Make sure there's nowhere it can ground (bare spots, cracked insulation, etc.). If it does ground, the alternator goes full field and will throw way too many volts at the system. The '81 Imperial I had in the '90s had that issue, and it was near 18V at idle, 20V plus at cruise.
Jester
In through the Out Door, so She's
I think the voltmeter issue has something to do with the way I disassemble it and place it in the gauge cluster. Maybe it moves a bit and then jams the lower part of the needle against the cluster frame. Maybe I should just buy one and leave it in its own housing, wire it up and see what happens.
I have a digital voltmeter which plugs into the cigarette lighter, and it never goes over 14.55v... Seems close enough to specs, drops to 13.2ish at slow idle.
I have a digital voltmeter which plugs into the cigarette lighter, and it never goes over 14.55v... Seems close enough to specs, drops to 13.2ish at slow idle.
thrashingcows
Drowning deep in my sea of loathing...so I'm
Pics or it didn't happen Jester...
Jester
In through the Out Door, so She's
Sure. Now this gauge is broken too. Stuck at 10 volts once I turned the engine off.
I could have lowered the gauge face a bit, but the way I attached it, gave the needle the most clearance to prevent jamming it against something. No idea why they keep breaking, must be my two left hands...
I could have lowered the gauge face a bit, but the way I attached it, gave the needle the most clearance to prevent jamming it against something. No idea why they keep breaking, must be my two left hands...
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Dr.Jass
Pastor of Muppets
Your plug-in voltmeter tells me it's a mounting or wiring issue with the gauge itself. I totally understand wanting to use the existing opening, but unfortunately Chrysler's long-running affair with ammeters makes for slim pickins at the boneyard for a factory voltmeter that might go in there. It's possible something from a FWD car might fit in there, like an Omni or K-car; anything further upmarket had a fancy needle that would look even more out-of-place than your oversized gauge face.
Perhaps you should stray. GM pickups and F-bodies gave up their ammeters for voltmeters in the '70s, though I'm not sure what year each changed. Firebirds had them by 1977 for sure. One of their offerings might be a closer fit in your dash, and it would be designed to mount the same way as your OE ammeter. Obviously, the ammeter wiring needs to go away, which it seems you've already done.
Perhaps you should stray. GM pickups and F-bodies gave up their ammeters for voltmeters in the '70s, though I'm not sure what year each changed. Firebirds had them by 1977 for sure. One of their offerings might be a closer fit in your dash, and it would be designed to mount the same way as your OE ammeter. Obviously, the ammeter wiring needs to go away, which it seems you've already done.
Jester
In through the Out Door, so She's
Hmm... Took GoldMember for a drive (to recycle some cardboard and styrofoam at the dump), and noticed something. When I turn the key off from running, it energizes the starter for a split second. I believe that's exactly when the volt gauge(s) fried.
The volt gauge needle even moved when I turned the key off. That was the only time it moved. Also, my turn signal bulbs in the dash are not working.
This calls for some investigating... But I need to make a beer run first.
The volt gauge needle even moved when I turned the key off. That was the only time it moved. Also, my turn signal bulbs in the dash are not working.
This calls for some investigating... But I need to make a beer run first.
Jester
In through the Out Door, so She's
I was thinking it may be related to a relay that was wired into field wire/voltage regulator years ago, to bring the charging voltage down. Also has a fused wire from alt to battery, as well as a ground run from alternator body, to ecu body, to voltage regulator body to negative batt. terminal.
Will have to see how the relay is wired up.
Will have to see how the relay is wired up.
Dr.Jass
Pastor of Muppets
I assume the relay was so the field wire's connection could be broken during overcharge situations, since that's the only way I can see a relay affecting charging voltage. That's a "get you home"-type fix, not something I'd run perpetually. With your cigarette-lighter voltage gauge reading what it does, I'd get rid of the relay. It's completely superfluous and simply one more thing that can fail.
I can understand the redundant grounding, since those points seem to become more critical with age, but I think I'd rather see "to block" everywhere you have "to body" written. Your main ground cable goes to the engine--or at least it once did--so that's your best ground source other than battery (-). At some point in the past, there was a ground wire or strap going from the back of the engine to the firewall. If it's gone, replace it and if it's there, check its condition. The factory wiring on these cars, contrary to popular opinion, is actually pretty damned simple and solid. The #1 issue with it is years of non-maintenance. I mean, who thinks to disassemble and clean the junction block at the firewall?!
I can understand the redundant grounding, since those points seem to become more critical with age, but I think I'd rather see "to block" everywhere you have "to body" written. Your main ground cable goes to the engine--or at least it once did--so that's your best ground source other than battery (-). At some point in the past, there was a ground wire or strap going from the back of the engine to the firewall. If it's gone, replace it and if it's there, check its condition. The factory wiring on these cars, contrary to popular opinion, is actually pretty damned simple and solid. The #1 issue with it is years of non-maintenance. I mean, who thinks to disassemble and clean the junction block at the firewall?!
Jester
In through the Out Door, so She's
"Body" is referring to the case of ecu, voltage regulator etc. (The ground loop)
I installed a new ground wire from batt to engine block years ago.
Pretty sure the relay was put in to give the field wire straight battery voltage without going through all the voltage drop areas, but only when the ignition is on. This is probably the problem area.
I cleaned up the main junction block at the firewall and used some dielectric grease on there.
Hmm... Going to tear out the relay and wire it up as it should be.
I installed a new ground wire from batt to engine block years ago.
Pretty sure the relay was put in to give the field wire straight battery voltage without going through all the voltage drop areas, but only when the ignition is on. This is probably the problem area.
I cleaned up the main junction block at the firewall and used some dielectric grease on there.
Hmm... Going to tear out the relay and wire it up as it should be.
Dr.Jass
Pastor of Muppets
As I recall, one field wire should get battery voltage from the 12V side of the ballast resistor, which also feeds one wire (the blue one) at the regulator. The other field (green) is wired directly to the voltage regulator.
My guess--and this is just a guess at the moment--is that you're getting a voltage spike in that field wire, something called "flyback", when the relay de-energizes. The larger the coil, the larger the flyback... and you've got an entire field coil's worth of it (a metric shit-ton). In that brief moment of shutdown, that voltage spike across the field could be well over 50V, which would make that last bit of alternator rotations really, uh, effective. Essentially what's happening in that split second is the similar to what's happening in your ignition coil every time it fires. The high-voltage coil excites the lower one, the field voltage goes wild, and it all goes out using your main power wire as a spark-plug wire, so to speak.
Ditch the relay, wire as OE, and I bet your gauge woes stop immediately.
My guess--and this is just a guess at the moment--is that you're getting a voltage spike in that field wire, something called "flyback", when the relay de-energizes. The larger the coil, the larger the flyback... and you've got an entire field coil's worth of it (a metric shit-ton). In that brief moment of shutdown, that voltage spike across the field could be well over 50V, which would make that last bit of alternator rotations really, uh, effective. Essentially what's happening in that split second is the similar to what's happening in your ignition coil every time it fires. The high-voltage coil excites the lower one, the field voltage goes wild, and it all goes out using your main power wire as a spark-plug wire, so to speak.
Ditch the relay, wire as OE, and I bet your gauge woes stop immediately.
thrashingcows
Drowning deep in my sea of loathing...so I'm
Do you still have a collector plate on GoldMember? What is your cost per year nowadays?