Dim lights

[The Wingnut]

Just noticed this last night. I think that my alternator is going out, but I'm not sure. My lights are very dim, both the headlights and the instruments. The wipers almost don't move at all. The ammeter is reading a negative charge with the engine running.

Anything other than a bad alternator that could be the cause? I'll probably buy a new alternator tomorrow, but I want to be sure I'm fixing the right problem before spending a load of dough.

[seerex]

Other than taking it down and having someone test it, check your connections on the alternator and around it to make sure you don't have a bad cable but probably alternator,just have it tested first .

[Bambikiller240]

Also, if the car has the external Voltage regulator, it is usually advisable to replace both it and the alternator if one or the other is deemed bad. When one fails, it often tends to cause damage to the other.

[Alex 240Z]

I noticed when I put my car in the garage a few days ago when I hit the gas pedal the lights got brighter and when it idled down they got dimmer could that be my voltage regulator is going ??????????

[Bambikiller240]

Not necessarily. The alternator output on 240Z's (especially the early ones) is considered marginal. At low RPM's Alt. output may not be sufficient to power Engine, Headlamps, instrumentation, heater fan, stereo, etc.

[dogma420]

Carl,

Do you know anyone that makes a higher output alternator for our 240s? Like a new one, not made for another rig, but specifically you ask "I need a high output alt for my 72 240z?"....I am sure there are other years that might work, or other cars' alternators.

Have a Zed day man,

[bpilati]

I think I got a later model alternator that puts out about 10A more, but it has a modern external regulator.

[Bambikiller240]

The earliest 240Z's originally came with a 45-Amp Alternator which was replaced at some point with a 50-Amp unit.

Victoria British currrently offers 50-Amp and 60-Amp Alternators for 240/260Z's. (I believe that MSA also sells them)

Also, in our Tech Articles section is a write up about converting a 240Z to an Internally Regulated 60-Amp Alternator from a 78 280Z

http://www.classiczcars.com/forums/showthread.php?t=5997

[72' 240]

Hello again zfellows of cyberland,

I have had a great deal of luck with a zx alternator. There is a set of instructions for the proceedure on a nissan tech website, I believe (not a Nissan authorized tech site, just a Nissan "tech" site). It involves keeping the internal regulator and by-passing the external one. This really is relatively easy, and if you do it right, you simply place a "dummy plug" on the harness and alter nothing that is original. The dummy plug in the harness must be wired according to the instructions as to properly reroute the electricity allowing the internally regulated alternator to work. This is accomplished very easily by connecting the colored wires together as instructed, and properly insulating them. The dummy plug simply is the old one from the old or any old 240 regulator that might still be lying around (I seldom throw any old parts, etc. away). There is a diode mounted (stripe towards the alternator) in the primary line to the alternator. This diode is readily available at Radio Shack.

To show the car, etc., just remount the original. No harm, no foul (Of course you may not want to power-up the new electric nose hair trimmer/denture cleaner once the old alternator is back on-line). :disappoin

Mine has been a great relief, as I am not replacing alternators every few months. I can also add a reasonable number of "add-ons" (stereo, etc) without fear of overload.

Heck, I had a 96' maxima SE 5-Speed (loved it), that dimmed everytime I hit the power locks, but never gave me any real trouble however.

[Bambikiller240]

Hello again zfellows of cyberland' date='

I have had a great deal of luck with a zx alternator. ..............[/quote']

Same Alternator upgrade as described in our forum (I believe that it's the same alternator in fact)

[bpilati]

I don't remember which alternator and its output he installed. It was part of some other repair work and I didn't even know the alternator was bad.

[The Wingnut]

Just an update to my situation, after a careful check of the regulator (which looked brand new inside, with almost no wear to the points at all) and all connections, I replaced the alternator and immediately showed about 20 amps positive, which has tapered off to neutral over the past day or and a half. Switching on the lights causes a very brief momentary drop, after which the needle returns to the neutral position.

Am I right in thinking it showed so much positive charge because the battery had been drained from driving and using the lights? I seem to have full charge, and all of the electrical systems function as they should. It would makes sense (at least to me) that the indicated charge would read less as the battery was recharged.