Nissan URVAN SD23 1984 van (hearse) - Alternator Problems

[Spacewalkingninja]

Hello!

I've got myself a nice hearse converted camper, it's been almost a year now, and so far I've been having only minor issues, which I was *somehow* able to work out on my own while digging in old Nissan/Datsun Urvan and 720 manuals. Nothing serious, my biggest problem till now was I had no brakes and gearbox wasn't changing gears DUE to a brake fluid leak under the front right wheel and I ended up purging it all out and filling it anew after changing the leaky pipe. Fixed, for some 8 months no problems whatever.

Last weekend, I had a long trip in the cold and demanding somewhat higher than normal amperage from the alt (I had stereo, Blower on hot, low/high beams driving for some 8hrs and a portable 12v chiller all hooked up). Next day, having rested, and started again at some point after 4h+ driving non-stop, motor and everything is well hot, after a nasty bump and asensed the smell of something cable-y meltin', which I couldn't account where it came from as as after a visual inspection vehicle was OK and Idling OK on the side of the road, NO MORE SMELL. Restarted driving, and some miles/kms down the road my CRG and BAT lights on the Combination meter came on.

Stopped car again, visually Alternator was & untill now it does spin. The belt is well tightened. Can't spin it by hand obviously.

Somehow my Battery managed to get me home for the last 50km leg of the trip.

Monday till now I've been figuring it out like a monkey and here is what I found out:

Battery charges good, not new but works OK (recharged at home 4 times this week because after 10 cranks it dies) 

Voltage from memory: 12.9 when charged 100%, 12.6 after a few cranks no charge, 12.5-12.4v while idling with no alternator.

Sounds bad as for alternator/charging circuit.

Checked fuses and fusibles. 
I SUSPECT 90% one fusible link is out, why? I got multimeter continuity from pos terminal to the L/S cables that go in the alternator, but one of the cables that split from the BAT + Terminal has a fusible link that's blown (No continuity). What I find odd is that when I shunt it, the vehicle behaviour doesn't change. 

Tests performed // The saucy part: 

When I shunt from the battery to the L terminal on the alternator, both CRG and BAT lights on the dashboard, comb. meter, speedometer turn OFF!! 
Then car cranked and running in this shunted state multimeter reads the usual dead 12.5-12.4V out when measured on battery, I didn't get the expected 13-14v, before doing this test I made sure I got Continuity from alternator big red + to Bat.

I do have 0v on the ONE of the two wires with IGN on and battery plugged. When key at IGN checked that I DO have 9-climbing up to-10v at what I'd suspect is the L terminal.

I do have continuity from CRG / BAT lamps on Comb Meter to L/S Terminals.

I've been using the 720 manuals & schematics so far.

 

Will post pics ASAP! 

[]2eDeYe]

Welcome, would love to see those pics 😄

[Spacewalkingninja]

 

 

 

 

 

 

Still gotta fix this:

[datzenmike]

Would like to know how transmission wasn't changing gears because of a brake leak. I suspect you mean the leak was in the clutch hydraulic line???

 

Fusible links all connect to the positive battery terminal. If they don't show continuity then replace. This should get your charging system back working.

 

 

We only got the 'Vanette' from '87-'89 and with the largest Z24 gas engine. It was plagued with over heating problems and discontinued. Nissan bought back as many as they could and scrapped them. Originally it would have had a much smaller engine but for N Am a too large 2.4 liter engine was selected and t was a disaster. Those that didn't trade theirs in really like them.

 

Did not know they were available as far back as '84 nor did I know they were diesel.

 

 

[Spacewalkingninja]

49 minutes ago, datzenmike said:

Would like to know how transmission wasn't changing gears because of a brake leak. I suspect you mean the leak was in the clutch hydraulic line???

 

Fusible links all connect to the positive battery terminal. If they don't show continuity then replace. This should get your charging system back working.

 

 

We only got the 'Vanette' from '87-'89 and with the largest Z24 gas engine. It was plagued with over heating problems and discontinued. Nissan bought back as many as they could and scrapped them. Originally it would have had a much smaller engine but for N Am a too large 2.4 liter engine was selected and t was a disaster. Those that didn't trade theirs in really like them.

 

Did not know they were available as far back as '84 nor did I know they were diesel.

 

 

Hehe! I found that out quickly enough, I was scared it could be the gearbox, but once I started reading online and the manuals that explain that the same hydraulic system is used for both brakes and gears it all made sense. This was some time ago. Now I just check my DOT4 level and if it's good, I-m good, if not, I will top it up. I gotta get myself a new boot for the gearbox. Some junkyard is my best bet probably?

 

Now the main question I have is> with BAT installed in car, and alternator installed or not, should I get +/- 12v on both L and S alternator terminals ?

Because the way I read it, the car is sending 9-10v on one of them and the other is reading 0V. This is with the alternator connector connected to the car or disconnected.

I'm asking because there's a lot of sources saying that both L and S should get 12v or near it.

 

 

Here is some info you probably know, I found in forums, the original PDF seems to be lost:

 

1. Terminal L must receive voltage. (on one terminal I receive 9v climbing to 10v on IGN)

This voltage is provided by the indicator lamp on most vehicles.

Failure to have voltage at terminal L may cause:

No charge, Indicator lamp OFF.  (When I shunt from battery to the yellow in my case cable on the ALT, this is the behavior)

Charges OK, but indicator lamp is ON.

Will not charge unless engine is “revved” up. Indicator lamp may come on when unit begins charging.

 

2. Terminal “S” must have battery voltage.

This voltage is supplied directly from the battery and will be present at all times. Failure to have voltage at this terminal will cause:

Overcharge or no charge condition, depending on alternator design.

 

3. The “BAT” terminal must have battery voltage. This voltage is supplied directly from the battery and will be present whether the ignition switch is in the “ON” or “OFF” position. Failure to have voltage at this terminal will cause: No charge, indicator lamp on. Extremely high voltage at “BAT” terminal. Possible damage to alternator diodes

 

I will try to determine which is S and which is L by disconnecting the battery and measuring continuity with the dashboard combination meter. I guess that L should have continuity with the "idiot lamp", and S should not.

[Spacewalkingninja]

PS I only read it now, will replace all fusibles on the battery harness, be it with car fuses inline or or shunt them to quick check if there is something energizing afterwards. Will post updates when I have more info!

[wayno]

There are all sorts of issues with the alternator when the fusible links are compromised, my glow plug light doesn't even work properly when that fusible link is blown/not making a good connection, also the plastic fitting that connects the fusible link section to the battery can melt and the connections can be compromised, meaning it looks connected but is not making a good contact/connection, this could possibly be the reason for the smell you mentioned, I had nothing but issues including charging issues because of that connection to the battery, unfortunately I do not have my camera with me to take a photo of the melted plug as I am driving the truck to today with that melted plug, but it is making a good connection now as I cannot buy them fusible link harnesses, so I make what I have work.

 

I am not sure if putting a fuse there is a good idea, them fusible links are there to keep one from melting the harness itself, a regular fuse might cause issues, to repair a fusible link you would need to buy fusible link wire/material and install it yourself in the fusible link harness, but I suppose one could temporary put a fuse there to see if that is the issue but using a fuse full time could make that a landmine waiting to...........................

[datzenmike]

Fusible links have the advantage of needing 5 or 10 seconds before blowing when carrying a load more than their ratting. A regular fuse blows instantly so if you are going to use a regular fuse carry extras and make sure they are the same rating as the fusible link they replace and not larger.

 

Does your ignition charge light, light up when you turn the ignition key to ON? If not then the bulb is blown or the number 4 fuse in the fuse box or it's the fusible link. You already said you suspect a fusible link so fix this first. The ignition light bulb actually supplies a slight 'trickle' charge to the alternator field coil to generate a magnetic field. Without it working it won't charge properly.

 

 

[thisismatt]

One side of the charge lamp gets +12V from the ignition switch ON, flowing to the alternator. Once the alternator is spinning and excites, it outputs +12V to the charge lamp and cancels out the voltage potential across the lamp, turning it off. Sometimes you'll get a little glow out of the lamp when you get a voltage drop on the ignition side, say from other ignition switched devices.

 

[Spacewalkingninja]

18 hours ago, thisismatt said:

One side of the charge lamp gets +12V from the ignition switch ON, flowing to the alternator. Once the alternator is spinning and excites, it outputs +12V to the charge lamp and cancels out the voltage potential across the lamp, turning it off. Sometimes you'll get a little glow out of the lamp when you get a voltage drop on the ignition side, say from other ignition switched devices.

 

This answer enlightened me quite a bit. I'm now thinking this is the alternator indeed, and not so much the wiring, might be time to take it off! Wasn't too curious to see how to disconnect an alt with oil inlets but that's how it is.

On 1/27/2023 at 3:37 PM, datzenmike said:

Fusible links have the advantage of needing 5 or 10 seconds before blowing when carrying a load more than their ratting. A regular fuse blows instantly so if you are going to use a regular fuse carry extras and make sure they are the same rating as the fusible link they replace and not larger.

 

Does your ignition charge light, light up when you turn the ignition key to ON? If not then the bulb is blown or the number 4 fuse in the fuse box or it's the fusible link. You already said you suspect a fusible link so fix this first. The ignition light bulb actually supplies a slight 'trickle' charge to the alternator field coil to generate a magnetic field. Without it working it won't charge properly.

 

 

On 1/27/2023 at 1:58 PM, wayno said:

There are all sorts of issues with the alternator when the fusible links are compromised, my glow plug light doesn't even work properly when that fusible link is blown/not making a good connection, also the plastic fitting that connects the fusible link section to the battery can melt and the connections can be compromised, meaning it looks connected but is not making a good contact/connection, this could possibly be the reason for the smell you mentioned, I had nothing but issues including charging issues because of that connection to the battery, unfortunately I do not have my camera with me to take a photo of the melted plug as I am driving the truck to today with that melted plug, but it is making a good connection now as I cannot buy them fusible link harnesses, so I make what I have work.

 

I am not sure if putting a fuse there is a good idea, them fusible links are there to keep one from melting the harness itself, a regular fuse might cause issues, to repair a fusible link you would need to buy fusible link wire/material and install it yourself in the fusible link harness, but I suppose one could temporary put a fuse there to see if that is the issue but using a fuse full time could make that a landmine waiting to...........................

Ok, so I double and triple checked the continuity on the fusibles near the battery, only one blown, I patched it with a fuse, and then straight to see what would happen, nada. Nothing poped, no smells, sadly no alternator. The van started up fine.

As for the ignition charge light, this one is definitively fine - it's what alerted me in the first place after the nasty smell. Actually it was exactly about this light I was asking if the second terminal that leads down to the alternator should be receiving 12v from the battery or the alternator, and @thisismatt answered - it is hot only when the alt is actually producing energy. It is not supposed to be hot on ignition. I too misunderstood the infamous schematic even though in hindsight it's quite obvious.

For future reference to anybody having problems:

 

A > Light On > Engine Idling > Light On > Faulty ACG and I get this result in all instances except when I shunt from battery to L, basically when I hack 12v in L. This sadly only shuts the charge lamp "CRG" and the battery / fuel switch lamp "BAT" but doesn't make the alternator kick.

I checked and the alt output IS definitely connected to the battery + terminal. The only test I haven't done is measure alt + and bat - with the car running, but by this point, even though I will check it, I'm quite sure it won't read anything different.

Here are some pics:

 

Dashboard with RED CRG Charge Lamp that goes to L terminal, and on the other side the orange BAT lamp

Dashboard of van running with the hack thing making the lamp go off, but voltage remains at 12.4-5, hence in reality there's no alternator.

PS: Yes, the previous owner wired a push to start system, I turn the key to IGN position, wait for the sparkplugs light to go off, then a relay pop (which? curiosity..) and push the button to kick the starter. Turning the van off is only with the keys.

The hac on the alternator L  connection.

Another dangerous hack on the end of the positive harness that shunts the blown fusible.

The alternator connector without the hack applied. The yellow wire is the L connector. The white wire must be the S connection as it receives 12v. The black connection should be negative,.. right?

 

Dash lights when car is on without the hacks. When I fixed the fusible it's still the same.

 

 

 

 

[thisismatt]

Oil lines on alternator? Not a vacuum line for the brake booster?

[Spacewalkingninja]

2 minutes ago, thisismatt said:

Oil lines on alternator? Not a vacuum line for the brake booster?

Not sure if it's oil or vacuum, I'm learning it on the go.. You can actually see the one of fittings in the photo of the alternator without the hack, black curved tube going to a metal pipe.

[thisismatt]

Ah, looking further I guess it's oil lubricated, but still a vac pump for the booster

[wayno]

7 minutes ago, thisismatt said:

Ah, looking further I guess it's oil lubricated, but still a vac pump for the booster

 

Yes, it is for the brake booster, diesels do not create enough vacuum to make them work, it has an oil feed line, a larger oil drain line that goes back to the block, and a vacuum line for the brake booster.

[wayno]

OK, when you check the fusible links you have to remove them from the battery and harness, if you check them in position/plugged in to the wiring harness you will/can get back feed from the wiring harness itself that can show power even though the fusible link is blown, at least that is an issue on the SD22/SD25 engines with the inline injection pumps, it is a very complicated wiring harness, but it appears you have a VE type injection pump which is likely way less complicated, but I would still disconnect the fusible link section from the wiring harness at a minimum to test all the fusible links.

Edited January 29, 2023 by wayno

[wayno]

Here is my melted plug I mentioned before on my 720 diesel wiring harness, and it smelled like burnt plastic more than once, it got hot because it was not making a good connection/sparking/arcing, it has a good connection now and has not got worse, when not connecting properly my charge light would come on and the glow plug light would only flash instead of staying on.

 

[Spacewalkingninja]

22 hours ago, wayno said:

OK, when you check the fusible links you have to remove them from the battery and harness, if you check them in position/plugged in to the wiring harness you will/can get back feed from the wiring harness itself that can show power even though the fusible link is blown, at least that is an issue on the SD22/SD25 engines with the inline injection pumps, it is a very complicated wiring harness, but it appears you have a VE type injection pump which is likely way less complicated, but I would still disconnect the fusible link section from the wiring harness at a minimum to test all the fusible links.

Got the alternator off. Finally. Also, got the end of the positive harness off and semi-permanently fixed with a fuse, it was the lowest amperage fusible that was off. Will see the insides of the Alt, fix it and then I should be able to check if there are any more electrical problems. ATM, electrical connections all seem fine, continuity and voltage wise.

[Spacewalkingninja]

 

 

 

 

 

 

Says hitachi on the outside, I think probably it is the original unit. Managed to get it open without needing to open the oil vacuum pump thing. Will have to align it very precisely as the linkage to the rotor is a press fit gear. But the seal between the oil and electric parts seems good. A lot of carbon on the contact pads, brushes were worn out, on one side down to the conductor, grinding in the rotor contacts. All cleaned up now, tomorrow will search for new brushes. Will get bigger and grind if local stores don't have a perfect match. To get the brushes off, I had to desolder them from the pad. The windings seem good, one spot I haven't photographed will get some super glue to be sure. Electrically, no connection between ground or the outer element and the windings. Dumb question, as it's not a typical circuit.. How should I test the diodes, are them the big round thingies on the board?  No continuity between positive and negative pads on the connector. ALl paths I could trace seem ok.

Will write later.

[Spacewalkingninja]

Hello guys!

So, here's an update: Fixed it! It was the damn brushes, had to unsolder the old ones, clean the contacting surface very well, got new brushes the next day, soldered them in place. Started mounting it all back in one piece... broke the new brushes. My bad, as I hadn't disassembled the whole rotor assembly and it was that much more difficult to put it all back together. Still, two days later the local shop had a new pair of brushes, I soldered them and then very carefully assembled the whole thing back together. Without disassembling the oil vacuum pump thing either as I was afraid that finding the right gasket could be another ordeal.

Started up got 12,6v on the battery idling, patiently waited a bit to get her a bit warmer and revved her up a bit, bang on 13-13.5 volts!

 

Buy yourselves two pairs of brushes if you are in this situation, it's graphite and it breaks easily. Don't order online, go to your local car guy if possible - the guy here was selling them for 3 euros, online shops were like 10-12 euro. 

[datzenmike]

Rev it up with the lights and heater on. 13-13.5 seems a volt low. Also no charge at idle but suddenly jumping when revved is what happens when there is no power on the White/Blue wire to the plastic plug on the alternator. This normally induces a magnetic field to get things started. Without it there is no charge (12.6) but there is a small residual magnetic field in the metal. When revved up it kick starts the alternator and once it's charging it feeds itself.

 

Check that plug is snug in the alternator.

[Spacewalkingninja]

Why? Start troubleshooting if the melty smells were from that assembly haha? Will do it tomorrow and tell you the result.. Too tired, it's 3am here. But I'm positive it is doing things correctly now. Warning lights on the dashboard / combination meter are off now, no matter how much I revved up, before the fix , there would be no voltage increase.. so SOMETHING is working now haha!