LJ70 not charging

[Gubbtratt1]

I've decided that the time has come to work on the charging problem of my 1987 LJ70, 12v electrical system, 2lt engine. I have no idea where to start though, I haven't found anyone with the same problem.

A few years ago the regulator broke and it charged 20 volts until it blew up a battery. It then stood in a barn for a few years before I bought it. I replaced the regulator with one I bought from Autodoc. Now it doesn't charge at all. No dash lights comes on when I turn on the ignition either. The tachometer works and I've checked that the alternator is grounded. I believe I've also checked all wires between the alternator and the regulator, as well as the main charging wire between the alternator and the batteries.

 

[TheBussman]

the last one i had apart has a bad rectifier, open circuit. need to test all the components. expensive alternator to replace best to repair/rebuild if it has the built in vaccum pump.

 

[Gubbtratt1]

the last one i had apart has a bad rectifier, open circuit. need to test all the components. expensive alternator to replace best to repair/rebuild if it has the built in vaccum pump.

I just took it apart and measured the rectifier. No continuity either direction. I also measured the windings to make sure the problem weren't there, and they had continuity. Now I just have to source a new rectifier, neither autodoc, 4x4parts or motonet has them.

 

[TheBussman]

I just took it apart and measured the rectifier. No continuity either direction. I also measured the windings to make sure the problem weren't there, and they had continuity. Now I just have to source a new rectifier, neither autodoc, 4x4parts or motonet has them.

If you have a 70a alternator any 70a or higher rectifier that's the same size and style denso will work. I used one for a 5vz-fe but there are loads of other options out there. or if your brave you can solder in new diodes.

 

[Gubbtratt1]

I don't know if I can expect any answers since I already market the question solved. Anyways I looked up the alternator model and found exactly one rectifier that looked right. My alternator model wasn't on the list though.
The rectifier
States 100211-2750
I have a 100210-2750

My rectifier:

The sticker on my alternator:

TOYOTA
27030-54160
100210-2750
12V
DENSO MADE IN JAPAN

Will it fit?

 

[Rigster]

I don't know if I can expect any answers since I already market the question solved. Anyways I looked up the alternator model and found exactly one rectifier that looked right. My alternator model wasn't on the list though.
The rectifier
States 100211-2750
I have a 100210-2750

My rectifier:
View attachment 3854823
The sticker on my alternator:
View attachment 3854824
TOYOTA
27030-54160
100210-2750
12V
DENSO MADE IN JAPAN

Will it fit?

I suspect it would work, but would advise to contact the company selling them to verify before purchase. Alternators all work with the same concepts, it would be down to amps and number of diodes.

 

[Gubbtratt1]

I suspect it would work, but would advise to contact the company selling them to verify before purchase. Alternators all work with the same concepts, it would be down to amps and number of diodes.

I'm pretty sure it works, as it has the same amount of diodes and the same general design. The question is if it will fit, or if it's the wrong size or the mounting studs are at the wrong locations.

Looking closer at the listing I noticed it says "diode a: 35". Does that mean the entire rectifier can only take 35a, or do I have to double that to 70a since there's two diodes per winding?

It also mentions "mounting distance: 71.5mm". A bit unclear to me what measurement that is, but I'll go check if anything matches.

Edit: the distance between the top and bottom mounting studs is about 7cm.

 

[Eurasiaoverland]

I'm not sure where the idea of 70A comes from. The original alternator for a 1987 European LJ70 (-54210) would have been 50A. Running the number on your alternator, it seems to be a 55A unit from a Hilux (or Hiace) from the same period. Any chance you can find an old Hilux alternator nearby? There are a couple on eBay in Europe but they are not cheap (around EUR 150 with shipping). The later 1988-97 European Hilux used a similar alternator and would be compatible.

My gut feeling is that the part you have found will work, though it won't be the same quality as an original Denso part. It's so cheap though, surely worth a try?

 

[Gubbtratt1]

I'm not sure where the idea of 70A comes from. The original alternator for a 1987 European LJ70 (-54210) would have been 50A. Running the number on your alternator, it seems to be a 55A unit from a Hilux (or Hiace) from the same period. Any chance you can find an old Hilux alternator nearby? There are a couple on eBay in Europe but they are not cheap (around EUR 150 with shipping). The later 1988-97 European Hilux used a similar alternator and would be compatible.

My gut feeling is that the part you have found will work, though it won't be the same quality as an original Denso part. It's so cheap though, surely worth a try?

I don't know if I mentioned it or not, but my alternator is most likely 55A, as you say. I was rambling about 70A wondering how much power the diodes can really take, and TheBussman kindly informed me that if it's 70A all 70A or higher Denso rectifiers will fit.

The part isn't too cheap when you add shipping to Finland, 48€ total. I might have to contact the Toyota dealer and see if they can get me a genuine part for a reasonable price. Otherwise maybe visit a scrapyard and see if they have any hiaces or hiluxes.

 

[Eurasiaoverland]

I don't know if I mentioned it or not, but my alternator is most likely 55A, as you say. I was rambling about 70A wondering how much power the diodes can really take, and TheBussman kindly informed me that if it's 70A all 70A or higher Denso rectifiers will fit.

The part isn't too cheap when you add shipping to Finland, 48€ total. I might have to contact the Toyota dealer and see if they can get me a genuine part for a reasonable price. Otherwise maybe visit a scrapyard and see if they have any hiaces or hiluxes.

I've never seen a 70A alternator in that old design. I can pretty much guarantee that the rectifier is no longer in production, plus even if it were, you could probably buy both complete eBay alternators (with vacuum pumps) for the price your local dealer would charge.

I'm sure I've come across Finnish 4x4 forums, maybe you can post a wanted ad there.

 

[Gubbtratt1]

I've never seen a 70A alternator in that old design. I can pretty much guarantee that the rectifier is no longer in production, plus even if it were, you could probably buy both complete eBay alternators (with vacuum pumps) for the price your local dealer would charge.

I'm sure I've come across Finnish 4x4 forums, maybe you can post a wanted ad there.

I'll se what I'll do, local scrapyard is probably first on the list.

The later 1988-97 European Hilux used a similar alternator and would be compatible.

Do those also use the external regulator, or would I have to convert the wiring to fit an internal regulator?

 

[Gubbtratt1]

Searching for hiace rectifier instead of land cruiser or denso 100210-2750 rectifier I found one on a finnish site. It is from china, but it's 20€ plus 9€ delivery, so even if it just lasts a few years it's probably a lot cheaper than a genuine part or a new alternator.

 

[Eurasiaoverland]

The base spec 1988-1997 European Hilux had external regulators as far as I know. I can say that for sure in the UK.

Higher spec versions (Xtra Cabs, IFS models) had internally regulated I believe.

The par on the FInnish site appears to be for a 40A alternator. I don't know enough about electrics to say if running that up to a theoretical 55A will be fine, but I suspect it will be OK.

 

[TheBussman]

I'm not sure where the idea of 70A comes from. The original alternator for a 1987 European LJ70 (-54210) would have been 50A. Running the number on your alternator, it seems to be a 55A unit from a Hilux (or Hiace) from the same period. Any chance you can find an old Hilux alternator nearby? There are a couple on eBay in Europe but they are not cheap (around EUR 150 with shipping). The later 1988-97 European Hilux used a similar alternator and would be compatible.

My gut feeling is that the part you have found will work, though it won't be the same quality as an original Denso part. It's so cheap though, surely worth a try?

70a was just an example. I didn't know the amperage, the last 2lt i worked on was 70a but newer model.

Searching for hiace rectifier instead of land cruiser or denso 100210-2750 rectifier I found one on a finnish site. It is from china, but it's 20€ plus 9€ delivery, so even if it just lasts a few years it's probably a lot cheaper than a genuine part or a new alternator.

Did you try spareto.com? Estonia is a lot closer to you and I'm surprised how cheap and quick they can ship to USA

 

[Gubbtratt1]

Did you try spareto.com? Estonia is a lot closer to you and I'm surprised how cheap and quick they can ship to USA

I just looked up the part number on .com, and I didn't find any alternatives that weren't on .fi, and none of them are from Estonia. I've settled on this one from Poland though, it's the cheapest and I will get it this week if I order today.

 

[Gubbtratt1]

I got the rectifier today, installed it, mounted the alternator on the car, and guess what? It works just as bad as before. I do believe the rectifier was broken as I measured the diodes individually after removing it, but there's some other problem. After doing some troubleshooting I have concluded that the wiring is fine, it's either the alternator, regulator or dashboard. I've done some measuring of the regulator and dash and both seems faulty. I can't get continuity either way through any of the diodes in the dash, and the regulator also doesn't have any continuity between any pins.

 

[Eurasiaoverland]

There should be either some fusible links close to the battery +ve terminal, or some large fuses (I think 'AM1' is for the charging circuit) which you could check.

You can open up the old mechanical voltage regulatiors and look for burnt contacts/coil.

If you perform the same check on your new rectifier, do you get the same result?

 

[Gubbtratt1]

There should be either some fusible links close to the battery +ve terminal, or some large fuses (I think 'AM1' is for the charging circuit) which you could check.

You can open up the old mechanical voltage regulatiors and look for burnt contacts/coil.

If you perform the same check on your new rectifier, do you get the same result?

I haven't checked fusible links because I haven't found them. I think some previous owner has replaced them with wires. There is 12v over the positive and negative terminal on the alternator when a battery is connected though, so both the main positive lead and the ground is fine.

I threw away the original regulator when I tried to fix the overcharging problem and now I regret it. The new regulator isn't mechanical.

I can't test the diodes individually since I already soldered the rectifier in place, but I could test the whole rectifier. For that to give a positive result only two diodes needs to be fine though.

I'll have to check the wiring diagram to make sure, but I'm starting to suspect a short to ground on one of the wires between the regulator and the dashboard.

 

[Gubbtratt1]

I've concluded that the short to ground I suspected is most likely the fuel shutoff solenoid. I also tested the dashboard with a battery and some wires, and everything lit up as it should. This means that the brand new regulator is most likely the problem. I've read on some Finnish forum that the ones from Motonet are the only reliable aftermarket ones, but those aren't available anymore. Would anyone happen to know about some other quality regulator available to Finland?

Edit: I found the manufacturer and their part number (Hella 5DR 004 243-09) on Motonets site and found it on some other sites, but twice as expensive as other brands as well as on Motonet. I might still buy it just to make sure that I don't get another faulty one.

 

[Eurasiaoverland]

I've concluded that the short to ground I suspected is most likely the fuel shutoff solenoid. I also tested the dashboard with a battery and some wires, and everything lit up as it should. This means that the brand new regulator is most likely the problem. I've read on some Finnish forum that the ones from Motonet are the only reliable aftermarket ones, but those aren't available anymore. Would anyone happen to know about some other quality regulator available to Finland?

Edit: I found the manufacturer and their part number (Hella 5DR 004 243-09) on Motonets site and found it on some other sites, but twice as expensive as other brands as well as on Motonet. I might still buy it just to make sure that I don't get another faulty one.

I'm pretty sure your alternator is externally regulated (I can't remember if you mentioned it). As you seem to be pretty competent with electrical circuits (certainly more than I am), I think you could grab any external voltage regulator from a 12V Toyota from the 80s or 90s if you can find one in a scrap yard.