Osoi Posted June 21, 2015 Report Share Posted June 21, 2015 I have a feeling it's the VR, but maybe you could help my get to the problem faster. Cold voltage measures 35v (I know... trust me, I benched it against a control. My meter is fine), upon load, it's getting 40v +- 2v. What's going on? Where should I start. He's (his name is Carl) is great otherwise. 1 Quote Link to comment
Osoi Posted June 22, 2015 Author Report Share Posted June 22, 2015 Seriously, can I get some input here? Does anyone want pictures, I need help. Ratsun.net seems to be the place to go, the place where people who know datsuns and can solve problems live. Help me here. 1 Quote Link to comment
DanielC Posted June 22, 2015 Report Share Posted June 22, 2015 Patience, dude, patience. Check the battery cables. I am assuming you have a close to stock alternator, you mentioned a voltage regulator. If the battery cables are good, and the battery is good, the stock alternator only puts out about 35 amps. The battery, assuming a good connection between it, and the alternator, will pretty much hold the voltage down close to its nominal voltage for a short period of time. 1 Quote Link to comment
datzenmike Posted June 22, 2015 Report Share Posted June 22, 2015 More info. What have you done to your 521 recently? Did you just recently replaced the alternator? Did you just replace the voltage regulator? Have you had the battery cables off? 1 Quote Link to comment
Osoi Posted June 23, 2015 Author Report Share Posted June 23, 2015 Whew! Ok thanks for the reply guys. Sorry, just excited to get on the road. Now. Here's full disclosure. I just bought this about 2 weeks ago, and I bought it fully aware it wasn't running. The guy said he had been through a litany of things, but was running out of patience. After owning a 78' Wagon 510 that had been easy to work on, I thought no problem.. but.... He'd owned it for a little under a year. Here's the list of things he had done to it in that time.Fuel line and Tank flushReplace distributor cap, rotor spark plug wires, and air filternew battery terminalsNew batteryOverhauled AlternatorI've included several pics for reference.To answer your questions:DanielC: Battery Cables look clean and solid. Look like they've been replace recently. I'm assuming in the last year by this guys mechanic. When you say "hold the voltage down close to it's nominal voltage" What are we talking about? Cause I'm measuring about 40 volts under load at the battery while the car is running. IT should be around 14 right? That should be a huge indicator of a VR issue right?datzenmike: I've done nothing - as listed above. Alternator was overhauled within the last year. Voltage Regulator - I've got one on order. As you can see from the photos, it appears to be the stock one. (by the way, I know it's not attached. I was having these problems while it was attached to the fenderwell) Haven't taken the battery cables off as they appear to be in fine shape. IT looks like there's a whole mess of things unplugged as the previous mechanic was trying to find the source of the problem by unhooking any extra thing, like the horn... Ugh. Quote Link to comment
datzenmike Posted June 23, 2015 Report Share Posted June 23, 2015 Right off I can see that the ground connection on the regulator is not screwed down tight. It's imperative that the regulator be properly grounded to the body. The negative battery cable is grounded to the head but you must also have a ground strap to the body. This can be to the battery or from the engine to the body. Might be me or the angle but those two wires don't look that tight either. 1 Quote Link to comment
Osoi Posted June 23, 2015 Author Report Share Posted June 23, 2015 Datzen Mike, As I said in my reply. The problems I had were BEFORE I removed the voltage regulator. It was just dangling there as I had taken it off the fenderwell to inspect it. It was firmly mounted, while the problems were going on. Here's a better description of the actual problem. Truck fires up wonderfully. Turns over on first couple cranks. Drives for 3-5 min. Dies. Wait 5 min, starts back up as normal. Drives 1-3 min. Dies. Wait 5 min, starts back up. Home safe. That's where I'm at. I'll double check the ground strap and the two wires on the alternator. 1 Quote Link to comment
MikeRL411 Posted June 23, 2015 Report Share Posted June 23, 2015 Two unconnected wires in the harness just visible above the battery. Much battery terminal corrosion visible. Voltage regiulator appears to be the old mechanical type, really should switch to the readily available plug for plug electronic type. The mechanical type is adjustable but after 36 years you have to got to wonder about the internal mechanical relays! I have the manufacturer and type numberof a reliable electronic VR which I have used for over 40 years but it's too late for me to go into the garage and rumage through the parts boxes / lists to get the manufacturer and part number. 1 Quote Link to comment
Osoi Posted June 23, 2015 Author Report Share Posted June 23, 2015 Ok. Double checked those Alternator cables. On very tight. I might take them off and scrub them down to remove any corrosion that might be there. But let me understand this, are you saying that in addition to the battery ground that's running to the engine block, there also needs to be a cable that runs from the negative battery terminal to the body? Thanks for all your help! 1 Quote Link to comment
Osoi Posted June 23, 2015 Author Report Share Posted June 23, 2015 Two unconnected wires in the harness just visible above the battery. Much battery terminal corrosion visible. Voltage regiulator appears to be the old mechanical type, really should switch to the readily available plug for plug electronic type. The mechanical type is adjustable but after 36 years you have to got to wonder about the internal mechanical relays! I have the manufacturer and type numberof a reliable electronic VR which I have used for over 40 years but it's too late for me to go into the garage and rumage through the parts boxes / lists to get the manufacturer and part number. Thanks! I have already ordered this : http://www.davesdiscountautoparts.com/catalog-1/itemdetail/standard-motor-products/vr-121?checkfit=y&make=nissan&year=1969&model=521-pickup What two wires are you talking about? I know the one next to the hood light (non functioning btw, along with the horn) 1 Quote Link to comment
datson4life Posted June 23, 2015 Report Share Posted June 23, 2015 Buy a 1982 or 84 subaru standard 1.6 alt (about$55), bolts right in, then take off voltage regulator and burn it in a safe area, then on the vr plug, jump wires a couple wires, give me a sec ill tell u the color of the wires, cant find the pic 1 Quote Link to comment
datzenmike Posted June 23, 2015 Report Share Posted June 23, 2015 But let me understand this, are you saying that in addition to the battery ground that's running to the engine block, there also needs to be a cable that runs from the negative battery terminal to the body? Thanks for all your help! YES! If you were 40 volts on the battery you may have fried some of the more sensitive electrical parts. That's three times what it should be. Fuses all ok? The starting and stopping may not be related to the charging system... probably isn't. 1 Quote Link to comment
datson4life Posted June 23, 2015 Report Share Posted June 23, 2015 Buy a 1982 or 84 subaru standard 1.6 alt (about$55), bolts right in, then take off voltage regulator and burn it in a safe area, then on the vr plug, jump wires a couple wires, give me a sec ill tell u the color of the wires, cant find the pic Ok, white to yellow and white/red to white/black But yes listen to datzenmike, battery ground to chassis is important 1 Quote Link to comment
Osoi Posted June 23, 2015 Author Report Share Posted June 23, 2015 YES! If you were 40 volts on the battery you may have fried some of the more sensitive electrical parts. That's three times what it should be. Fuses all ok? The starting and stopping may not be related to the charging system... probably isn't. Yes fuses are all intact. Weird salt like corrosion (on the inside of the fuse) on the regulator one though. But none of them are popped. 1 Quote Link to comment
Osoi Posted June 23, 2015 Author Report Share Posted June 23, 2015 What gauge cable would I need to ground the battery to the Body? Datson4Life, while I see that was a fix, I'm trying to restore this to as much OG as possible. So anything I can attempt (probably with massive failure) to restore to working order, I'm going to try. 1 Quote Link to comment
DanielC Posted June 23, 2015 Report Share Posted June 23, 2015 I am not as familiar with J-13 alternator wiring as L-16 alternator wiring. On an L-16 521, the battery is grounded to the head, and there is also a wire from the head ground connection to the frame of the alternator. There is a second ground wire from the frame of the alternator to one of the bolts holding the voltage regulator to the inner fender. An extra ground wire from the engine to the frame of the truck is a very good idea. If the engine. or alternator lose ground to the frame, oe cab sheet metal, things grounded to the cab sheet metal will then try to ground through the throttle cable, or the choke cable. You have "marine" type battery terminal adapters. The battery cables ideally should have a crimped or soldered battery terminal clamp that does not use any bolts to hold the cable to the clamp. When you get 40 volts, are you checking the voltage on the cable, on the bolts holding the cable to the adapter, on the adapter, or in the center of the lead post coming out of the battery? There is nothing wrong with a good working externally regulated alternator, and voltage regulator, if they are OEM Nissan parts. Nissan/Datsun electrical parts are pretty reliable. Aftermarket alternators, and regulators are nowhere as good as genuine Nissan parts. 1 Quote Link to comment
Osoi Posted June 23, 2015 Author Report Share Posted June 23, 2015 Do you have a picture example of the soldered battery terminal clamps you're talking about? When I get 40 volts I'm checking the center of the lead post. I could measure it right now and get 35 cold. 40 is under load at medium rev. So that should tell me, I don;t have a faulty alternator, but that my VR isn't regulating the amperage to the rest of the system right? 1 Quote Link to comment
DanielC Posted June 23, 2015 Report Share Posted June 23, 2015 Do the lights work? 40 volts will almost instantly cause the lights to burn very bright, and then blow out. These are the battery cables I made for the Canby truck. This is a better picture of the negative battery terminal end. 1 Quote Link to comment
datsunaholic Posted June 23, 2015 Report Share Posted June 23, 2015 If you were really at 40V every light bulb would be burnt out, the coil would have burned open, the battery would have boiled over (or at least started looking like a balloon)... all in less than 10 minutes. There would be smoking wires.. right away. I suppose it could be overvoltage making it die- because the coil is overheating. But a few minutes at 40V the lights and gauges would be dead. The worst I've ever seen with a blown regulator was 22V. And turning EVERYTHING on (except the wipers, it was too dry out) dropped the voltage to 15V. I have never seen an alternator voltage go UP when load is added. And at idle, the stock 35A alternator can barely keep up with lights and heater, if it even does, so even with a bad regulator the voltage would drop dramatically.. Are you damn sure your meter is good? How do you know this? Not reading AC volts? (if it were, that'd be a bad rectifier). What does your meter read at the battery with the engine off? 1 Quote Link to comment
Osoi Posted June 23, 2015 Author Report Share Posted June 23, 2015 I'm pretty sure the meter is good. Took a fresh AAA battery and read a perfect 1.5 volts. I'm getting 35.5 volts on the battery terminals with the engine off. 1 Quote Link to comment
datzenmike Posted June 23, 2015 Report Share Posted June 23, 2015 Impossible. Yes fuses are all intact. Weird salt like corrosion (on the inside of the fuse) on the regulator one though. But none of them are popped. Do not ever trust a fuse by looking at them. Test continuity or just replace them. 1 Quote Link to comment
Osoi Posted June 23, 2015 Author Report Share Posted June 23, 2015 Will do. That'll be step one when I get home tonight. 1 Quote Link to comment
datsunaholic Posted June 23, 2015 Report Share Posted June 23, 2015 I'm pretty sure the meter is good. Took a fresh AAA battery and read a perfect 1.5 volts. I'm getting 35.5 volts on the battery terminals with the engine off. Your meter is bad. Period. A 12V lead-acid battery cannot read 35.5 volts at rest. It's chemically limited to 13.2V. which is where it usually ends up after the "over" voltage (14.4V from the alternator) levels out. Your meter is reading almost 3X normal. Put it on a different 12V battery and you'll see. 1 Quote Link to comment
Charlie69 Posted June 24, 2015 Report Share Posted June 24, 2015 This terminal might be tight but the lock washer is doing no good. (Red circle) Loose the lock washer and put a flat washer on there instead. If you have room you can put a star lock washer between the nut and the flat washer. Quote Link to comment
Osoi Posted June 25, 2015 Author Report Share Posted June 25, 2015 Ok, UPDATE. Correct. Bad Meter. Cold 12.6, idle 13.8. Checked all the fuses, continuity is good. Where do we go from here? Quote Link to comment
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