1JZ vs 7M alternator useful info and pics

[Rcubed]

top right is CHG light [L - yellow/white wire] must have load or WILL NOT charge

Oh? I haven't found that... so you're saying that removing that wire will cause the alternator to stop running?
I've definitely had alts running (charging) without the light being hooked up so could you shed some light on your claim?

The Witzl's Quick Guide to Wiring an Internally Regulated Alternator

[Mos]

The Witzl's Quick Guide to Wiring an Internally Regulated Alternator

I'll rephrase my question - have you NOT connected a charge light, and have you found that the alternator was not producing a charging voltage, after which you did connect the charge light and found that the alternator did produce a charging voltage?

If you haven't done this, could you please quote the relevant section of literature as I have just skimmed through Witzl's thing and the autoshop pdf and have not found anything suggesting what you're saying (and I've hooked up more alts than Witzl has).

Mos.

[petergoudie]

Attached is a link to a great alternator site. It is an aftermarket manufacturer and you insert the alternator type or do a search and it shows all the important dimensions. From there you can compare alternator types; their interchangeability; and, find the exact dimensions to make another one fit in the same place. It also lists the amperage output for each model.

Also, I wish we all had Bosch alternators because over the years they have become very universal fit or if not most of the parts fit each other so you can simply just swap the front cover of a dead unit onto the back of another good unit and it fits. All the parts are available and slip rings might only be a few dollars up to about $10 (I think there are only two sizes for all alternators making it easy to choose).

Ingrams which I think is a national auto-elec supplier has a web site and is great for sourcing alternator bits or they will tell you where to find them. If you do use them keep asking to have all their data on the web and eventually they might do it. It can sometime take a bit of work in the catalogue to find interchangeable parts.

Here's the alternator site:

http://www.vicic.com.tw/alternators/altproducts.htm

[takai]

I'll rephrase my question - have you NOT connected a charge light, and have you found that the alternator was not producing a charging voltage, after which you did connect the charge light and found that the alternator did produce a charging voltage?

If you haven't done this, could you please quote the relevant section of literature as I have just skimmed through Witzl's thing and the autoshop pdf and have not found anything suggesting what you're saying (and I've hooked up more alts than Witzl has).

Mos.

I have, i buggered up the wiring on the charge light when i rewired the Sprinter (thought it went to ground), and i wasnt getting a charge from the alternator. Gave the charge light 12v and suddenly it jumped from 11.2v to 13.4v.

Possibly only certain alternators though, since the KE30 had a busted charge light (bulb blew) and it never had any issues.

[Rcubed]

I'll rephrase my question - have you NOT connected a charge light, and have you found that the alternator was not producing a charging voltage, after which you did connect the charge light and found that the alternator did produce a charging voltage?

If you haven't done this, could you please quote the relevant section of literature as I have just skimmed through Witzl's thing and the autoshop pdf and have not found anything suggesting what you're saying (and I've hooked up more alts than Witzl has).

Mos.

hi,
I haven't done this as i followed The Witzl's Quick Guide to Wiring an Internally Regulated Alternator, and have only wired up a few [3 now].

Did you miss this bit then?

A few notes.....

# If you do not connect the charge light, the alternator will not charge the battery

[cambelt]

MZ21 soarer 7M alternators are rated at 100 amps and will happy produce 110 amps.
Dave

[Mos]

I have, i buggered up the wiring on the charge light when i rewired the Sprinter (thought it went to ground), and i wasnt getting a charge from the alternator. Gave the charge light 12v and suddenly it jumped from 11.2v to 13.4v.

? Which part did you rewire? On the AE86 one side of the charge light gets power inside the cluster, the other side goes to the alternator through the charge fuse in the engine bay fuse box - which of these bits did you have to apply 12v to?

Possibly only certain alternators though, since the KE30 had a busted charge light (bulb blew) and it never had any issues.

That's what I suspected.

I haven't done this

That's also what I suspected - any chance you could pull your bulb or charge fuse out and see if it still charges?

Did you miss this bit then?

A few notes.....

# If you do not connect the charge light, the alternator will not charge the battery

Evidently However, I must dispute this statement, as I know for a fact that at least some alternators WILL charge without the charge light connected. I cannot make the statement that *all* alts will charge, but I highly doubt that a light bulb failure would result in loss of charging... must ask Witzl where he got that from

Mos.

[neal]

I was able to bolt a st162 3sge alternator on my 7m by accident and wondered why the mains cable wont fit, as in the 7m mains cable hole is smaller in diameter. Also the 3sge alternator is abit bulkier making the oil return from the head to block to interfear.

[Rcubed]

That's also what I suspected - any chance you could pull your bulb or charge fuse out and see if it still charges?

ok, i had about 15 mins today and i tried this.
first just tried the light disconnected ... start ... alt charges!
next disconnected the battery to ensure that there was no residual field or other transients persisting or being maintained [as if being installed for the first time] ... reconnect ... start ... alt charges!!
i'll have to stop quoting The Witzl

[petergoudie]

Be careful about checking alternators and disconnecting the battery with the engine running. I have read quite a number of times in manuals not to do this. The claim is the regulator needs a load on it to stabilze the voltage. If there is no load the output might go up to 60 or 80 volts which means cooked elecronics, computers etc.

[petergoudie]

MOS, this might be your answer regarding the light. I remember reading in an old Bosch manual that said sometimes after repair the field core around which the windings are wrapped might have lost its magnetism (as low as it is) and it needs to be magnetised before it will work. The manual said to momentarily short the output terminal to the battery (meaning a quick touch with sparks) - this is for alternators with an external regulator. Possibly this is done in the same way for an alternator with an internal regulator by using the current passed through the indicator light.

[Mos]

first just tried the light disconnected ... start ... alt charges!
i'll have to stop quoting The Witzl

Cool, thanks for checking it
No problems quoting Witzl If I hadn't definitely ran an alt without a light, I wouldn't have been so quick to question it. He would've had a reason for saying it; chances are there's more to the story.

Be careful about checking alternators and disconnecting the battery with the engine running. I have read quite a number of times in manuals not to do this. The claim is the regulator needs a load on it to stabilze the voltage. If there is no load the output might go up to 60 or 80 volts which means cooked elecronics, computers etc.

Peter, I think the issue is that the alternator does not produce a perfectly flat output, and the load due to a running engine is largly pulsed - the battery serves to smooth that out, like a large capacitor. I don't know the workings of the alt intimately but there is always a load present when the engine is running. It's easy enough to test this out as well, by isolating an alternator on a running engine using a second battery. In the above case, though, the battery was disconnected on a stationary engine.

In terms of over voltage protection, pretty much every ECU in a toyota has a zener diode across the power supply with a high enough current rating that it should (in theory) blow a fuse before damage to the electronics occurs.

Mos.

[petergoudie]

Mos, the overvoltage issue was also for light bulbs, instruments and fuel sender/gauges. The common answer given in manuals for bulbs blowing regularly is to check the output voltage of the alternator. This is why the manuals advise against disconnecting the battery with the engine running. Cheers.

["Z" UTE]

Another interesting snippet for the lads. The alternator on the UZS131 shares the same regulator pack, as the 7M, just in case you get stuck in the middle of nowhere.

A cross referece for all these electrical interchageabilities would be a great read. Anyone know if such a list has been complied?

cheers Chuck.

[cambelt]

A cross referance in part no,s would be great , theres really only 2 types with toyotas, round and oval plug. Most times you can swap in a reg out of something else. There are many diff genuine part no,s for the round plug reg , the difference between them generally the temperature offset of the charging voltage.
Dave