Electrical issues about to give up and burn it (1 Viewer)

[benno1990]

Got a 1985 hj60 I’m pretty good with mechanical and not bad with electronics but this car is a nightmare mechanic and auto sparky have no idea.

what it is doing is the charge rate is all over the place new alternator tried 2 now good earths internal regulator good battery only about a year old everything on it works including glow system it’s just alternator voltage wants to never sit above 14v with nothing turned on . In the morning it might start at 14.2 by the time you get anywhere it’s 13.8 or below and if you turn lights on it only gets lower I had to disconnect dcdc as it would jump around from 12.7v to 13.9v constantly I’m just at a total loss where to keep looking any suggestions

 

[pithicus]

Bad alt fusible link, or bad connection to the fusible link? Those fluctuations don't seem too bad. Did it use to be steadier before the new alts?

 

[benno1990]

Bad alt fusible link, or bad connection to the fusible link? Those fluctuations don't seem too bad. Did it use to be steadier before the new alts?

New fusible links already and upgraded charge wire from alternator also the voltage jumps around violently and fast

 

[pithicus]

voltage jumps around violently and fast

Sounds like a bad connection somewhere. Can be pita to find.

 

[benno1990]

Sounds like a bad connection somewhere. Can be pita to find.

Yea been looking for a year

 

[OSS]

Assume the volt meter in the cab is malfunctioning. Hook up a portable digital volt meter to the battery with an extension wire leading into the cab and use that to verify voltage.

A good alternator with good regulator, connected to a good battery with good wires will work perfectly.
There’s something in that equation above that’s missing in your truck.

 

[benno1990]

Assume the volt meter in the cab is malfunctioning. Hook up a portable digital volt meter to the battery with an extension wire leading into the cab and use that to verify voltage.

A good alternator with good regulator, connected to a good battery with good wires will work perfectly.
There’s something in that equation above that’s missing in your truck.

Its both volt metre got a digital one directly to battery as well

 

[CruiserTrash]

Its both volt metre got a digital one directly to battery as well

So the digital meter jumps around too? At the same time as the factory dash voltmeter?

Did you have the digital meter hooked up and in the cabin while taking it for a test drive?

My thoughts go immediately to grounds. Are all the ground cables (and there are a lot) in good condition? Are the bolts that hold them in place on both ends tight? Just to make sure the connection is good, did you make sure the area under the ring terminals was free of paint? The bolt threads will ground a cable but not if it’s corroded.

This is a 12V truck, yes? If it’s 24V, something that uses a center-tapped 12V might have a faulty connection. If it’s a 12V system you may still have a loose connection.

You can also look for a bad or intermittent connection by having a friend looking at the digital meter - set to voltage and attached to the (+) and (-) terminals of the battery - while you go around wiggling cables. Use a chopstick or other small piece of wood (not your hand or anything metal) to touch all the wires you can see. Give them a good bump in several places, especially around connectors, while your friend looks for the meter to go erratic. Have a fire extinguisher handy because that loose connection could be a dead short and cause a runaway current condition that will get hot fast. Better to find it when you’re prepared than when you’re driving down the road and smell smoke. You have a lot of wiring hidden inside of body panels, too, remember.

You can also check for parasitic current draw. Try removing the ground terminal from the battery, then connect one lead from a digital meter to the negative battery lug and one to the ground terminal. With the truck turned off, set the meter for mA of current. Any reading? How about if you look at the meter while somebody shakes the truck?

One more: any connectors you see, take them apart and check for corrosion. If you find some use something like Deoxit and a small pick or tiny flathead screwdriver to clean them. Make sure the connectors are dry before putting it back together.

Good luck

 

[benno1990]

So the digital meter jumps around too? At the same time as the factory dash voltmeter?

Did you have the digital meter hooked up and in the cabin while taking it for a test drive?

My thoughts go immediately to grounds. Are all the ground cables (and there are a lot) in good condition? Are the bolts that hold them in place on both ends tight? Just to make sure the connection is good, did you make sure the area under the ring terminals was free of paint? The bolt threads will ground a cable but not if it’s corroded.

This is a 12V truck, yes? If it’s 24V, something that uses a center-tapped 12V might have a faulty connection. If it’s a 12V system you may still have a loose connection.

You can also look for a bad or intermittent connection by having a friend looking at the digital meter - set to voltage and attached to the (+) and (-) terminals of the battery - while you go around wiggling cables. Use a chopstick or other small piece of wood (not your hand or anything metal) to touch all the wires you can see. Give them a good bump in several places, especially around connectors, while your friend looks for the meter to go erratic. Have a fire extinguisher handy because that loose connection could be a dead short and cause a runaway current condition that will get hot fast. Better to find it when you’re prepared than when you’re driving down the road and smell smoke. You have a lot of wiring hidden inside of body panels, too, remember.

You can also check for parasitic current draw. Try removing the ground terminal from the battery, then connect one lead from a digital meter to the negative battery lug and one to the ground terminal. With the truck turned off, set the meter for mA of current. Any reading? How about if you look at the meter while somebody shakes the truck?

One more: any connectors you see, take them apart and check for corrosion. If you find some use something like Deoxit and a small pick or tiny flathead screwdriver to clean them. Make sure the connectors are dry before putting it back together.

Good luck

I have done all earths already just redid them again its a 12v system tried what your suggesting already and get no results doesn’t happen all the time also digital volt metre and dash jump around together as i said the auto sparky couldn’t find it soo im here to see if there is something very specific to check like a relay or fuses or a plug etc

 

[CruiserTrash]

I have done all earths already just redid them again its a 12v system tried what your suggesting already and get no results doesn’t happen all the time also digital volt metre and dash jump around together as i said the auto sparky couldn’t find it soo im here to see if there is something very specific to check like a relay or fuses or a plug etc

Sounds like a pain! I think the chances are very high that there’s an intermittent connection somewhere, or that the insulation came off a wire and it occasionally touches something it’s not supposed to, or a corroded connector making intermittent contact.

I’ll try to think of other things that could cause a sudden & big current draw (and subsequent voltage drop).

 

[benno1990]

Its both volt metre got a digital one directly to battery as well

Sounds like a pain! I think the chances are very high that there’s an intermittent connection somewhere, or that the insulation came off a wire and it occasionally touches something it’s not supposed to, or a corroded connector making intermittent contact.

I’ll try to think of other things that could cause a sudden & big current draw (and subsequent voltage drop).

Side note once dcdc was disconnected yesterday it doesn’t jump voltage but as i drive voltage gets slightly lower starts at 14.1 and goes to 13.8-13.7 not too unusual but I would assume headlights or load would bring it up again with a 80 amp alternator but load drops it a little further

 

[OSS]

If the alternator wasn’t working at all, the battery voltage would be below 12.4V when the engine is running. So since you’re seeing 13.7 or so volts, that’s saying that the alternator is barely working.
While you said this is alternator #2, that’s no guarantee that it’s not a dud too. It seems unlikely, but it can’t be ruled out.
At this point, you’ve got to narrow down the unknowns. This new alternator SHOULD work fine, but it’s possible it’s not. I’d get it tested.
All your symptoms point to a bad alternator.

 

[CruiserTrash]

@benno1990 What is “dcdc”?

@OSS in two 60s I’ve had two alternators and four different voltage regulators (one original, one NOS, two no-name replacements). I’ve had a volt meter in the cabin of both trucks that reads true to a multimeter on the battery. On cold starts my voltage will be 14.2 and it will settle to 13.8 when driving during the day (no headlights or heater fans). It’s been the same voltage readings all the time. You’re saying 13.8V on a warmed up engine is due to a barely working alternator (or VR)? Just want to make sure I’m reading you correctly.

 

[OSS]

@CruiserTrash
Toyota says it shouldn’t drop below 14V no matter how big the load.
My newly rebuilt alternator never dropped below 14.3V when driving.

 

[benno1990]

If the alternator wasn’t working at all, the battery voltage would be below 12.4V when the engine is running. So since you’re seeing 13.7 or so volts, that’s saying that the alternator is barely working.
While you said this is alternator #2, that’s no guarantee that it’s not a dud too. It seems unlikely, but it can’t be ruled out.
At this point, you’ve got to narrow down the unknowns. This new alternator SHOULD work fine, but it’s possible it’s not. I’d get it tested.
All your symptoms point to a bad alternator.

It works fine in my 75 series so i would say it’s ok

 

[CruiserTrash]

@CruiserTrash
Toyota says it shouldn’t drop below 14V no matter how big the load.
My newly rebuilt alternator never dropped below 14.3V when driving.

View attachment 3195932

Interesting. Out of my two trucks and different alternator/VR combos it only reads >14V on cold starts, and always at 13.8V (+/- 0.1) when warmed Up and nothing on. Yeah, maybe if I’m stopped/idling and have the high beams, 200w aux lights, heater fans, and wipers going it will dip to 12.5V. I’ve measured both straight off the battery and my aftermarket cabin voltmeter. The cabin voltmeter is down 0.1V from the battery measurement and is otherwise accurate to the DMM.

I was thinking about it and I’ve actually had three alternators, not two. Two were original and one was rebuilt by our local old-school alternator rebuilder shop that specializes in Denso and Japanese stuff. When I walked in with the alternator the guy looked at it and said “Is this from a 60 Series Land Cruiser?” before I opened my mouth. I’ve had original VRs, a couple from NAPA, and a NOS one from ToyotaMatt. Voltage is always the same. My ground cables are all larger gauge and my alternator charging wire is 4awg through a MIDI fuse.

So what gives do you think?

 

[OSS]

I’m no alternator guy so I’m only guessing, but as I understand it (maybe incorrectly) is that the voltage regulator’s job is to prevent over charging by keeping the peak voltage within acceptable limits (below 14.6V). I don’t think it has any influence at lower voltages except to just pass full current.
A lead acid battery won’t get charged charging at 13.8 to 13.7 volts. That’s a float voltage (high float voltage) for lead acid.
Lets say you had a 12V fridge and went camping with the fridge running intermittently over night. Lets say it depleted the battery 50% overnight.
If you had an alternator that only put out 13.8V, the battery essentially would never get recharged while running the engine.
A little current would flow in - but not much. Certainly not much in the few hours the engine was running during a drive.

 

[CruiserTrash]

@OSS i’ll start checking my battery voltage with the DMM in the morning. I should also mention that over the time all of this data was collected I’ve had three different batteries - one used and two new (Napa, Interstate). No clue what else could be at play here to keep me at 13.8V. I occasionally measure parasitic load when the truck is off and always get 0.00mA - nothing.

 

[george_tlc]

Does you internal regulator alternator have the typical L/S terminals? L goes to your dash warning light and probably to glow timer etc (at least it does on my diesel patrol). The S is the sense and should connect as close as possible to the Battery+. The S is how the alternator determines battery voltage (ensures no voltage drops versus sensed directly at its own output post).

Given you've changed alternators and had different batteries, I'd suggest checking all wire integrity to/from the alternator to battery etc, carefully.

I presume you're also using a decent meter for your measurements, not some HF $3 freebie. Also you should be measuring voltages with the engine at around 2k rpm to ensure the alternator is in its working range for your measurements.

cheers,
george.

 

[CruiserTrash]

Does you internal regulator alternator have the typical L/S terminals? L goes to your dash warning light and probably to glow timer etc (at least it does on my diesel patrol). The S is the sense and should connect as close as possible to the Battery+. The S is how the alternator determines battery voltage (ensures no voltage drops versus sensed directly at its own output post).

Given you've changed alternators and had different batteries, I'd suggest checking all wire integrity to/from the alternator to battery etc, carefully.

I presume you're also using a decent meter for your measurements, not some HF $3 freebie. Also you should be measuring voltages with the engine at around 2k rpm to ensure the alternator is in its working range for your measurements.

cheers,
george.

Boy, seems I’ve hijacked this thread until we hear back from @benno1990.

The VRs are that type yes. The charge wiring, though upgraded to brand new 4awg, is the same length as stock. As a reminder, I’ve seen the same conditions in two different 60s.

My DMM for auto purposes is in fact a Harbor Freight meter (I have four or five meters at last count, I wanted a cheapie for throwing in my breakdown/recovery bag). Surprisingly the voltage measurements on it within the middle of the range are within less than <1% accuracy as compared to my 1940s Navy-issue VTVM and my Tektronix scope. No complaints.