Hello all,
I’m so frustrated! I purchased a rather nice 2+2 form Austin, TX and imported it to Switzerland. During the last year I fixed most of the issues I discovered here and there. I thought all was sorted out until I learned on my first longer trip that there is no charging.
It was already converted to a nippondenso alternator. But the wiring wasn’t done properly. No ignition warning light. Fixed that with proper rewiring. So that comes on with ignition and goes out with engine runnig.
I tested the 4TR resistance seem ok. So I suspected the alternator. Bought a remanufactured one from Rockauto which I just finished putting in. Unfortunately I see no change, i.e. no charge.
With engine running the ammeter shows 12V.
Did the 4TR test with disconnecting the terminals and putting a jumper to F and -. But the ammeter doesn’t move at all. Not even to 12V.
It can’t be that this replacement alternator is not working, right?!
Have you tested the reading across the battery with the engine at say 1500rpm? Also, have you checked that the alternnator relay is working as it should? All sounds like a wiring problem. Another thought…does you alternator have an on-board regulator? If so, do you need the 4TR in circuit?
Hi Les,
no, I haven’t taken any reading accross the battery. Given the results I got from the other tests I wouldn’t expect any new findings.
You mean the 6RA? Well, I have 12V on the + connector of the 4TR with ignition on. So that should be ok.
It’s exactly the setup described by CoolCat. So it’s the alternator which needs the 4TR.
The nippondenso requires an odd wiring trick. The field is internally connected to B+, so if you don’t have a way to interrupt ground when the engine powers down, the field will be full powered and the battery will drain quickly, not to mention potential alternator damage. This has to be accomplished with an extra relay.
I’d begin by reviewing the wiring diagram carefully:
It’s odd that the light goes out, that would indicate that there’s at least some AC current being generated. Rather than the FSM test, try jumpering the F- pole on the alternator to ground, which is the same test with the wiring eliminated. If the voltage starts to climb, shut down the motor immediately.
Remove the wire at the F- pole on the alternator, then ground it (the alternator F-, not the wire). Start the engine, and observe the voltmeter in the dash. Stop the engine when if goes above 14V.
Now 'm really confused. When I wanted to ground the F- pole I produced sparks. The multimeter shows battery voltage on F-. I assume that’s not supposed to be…
The Nippondenso field + is internally wired to B+. So you will ALWAYS have voltage at F-, thus the spark. Measure it…it should be something less than 12V, since it’s passing through the field coil. But let’s try something a little less scary. What I want you to do is Simply turn the key to “on” and measure the voltage on the F lead of the VR. If I knew that I’d have a better idea of what was going on.
The voltage on the F- on the alternator was exactly the same as on the battery. 12.7
On the F pole on the VR it’s 12.5 with ignition on. Interestingly that’s higher than on the battery at the same time where I read only 12.3.
Did the test with grounding F- alternator pole while the engine is running. General comment, the gauge is creeping very slowly to the below the 13V mark. So 12.6V which the battery has.
Ignition light stays on. When grounding, ignition light goes out, courtesy light goes bright for just a short moment but the gauge doesn’t move.
This really sounds like one or more open diodes. The fact that you have voltage atl the way to the F connection on the VR means the following are working: slip rings, brushes, rotor, alternator relay, aux bosch relay. The fact that results aren’t improved by grounding F at the VR means that the VR isn’t the problem. The fact that the light goes out means there is AC current in the stator (I assume you are using the 3AW.) Since you have 12/6 at the battery, it’s unlike to be a shorted cell. Which pretty much only leaves the diodes. Unless…could you start the car and measure voltage across the two battery terminals with a multimeter? Report the result.
Yes, the 3 AW is in place.
Voltmeter showed 12.6. With courtesy lights and ignition on it dropped to 12.3 and falling. Cranking it went to 10.1. With engine running I read 12.4 going to 12.45. Staying there regardless of engine speed.
Adrian, your original post states you are frustrated. It sounds like that may not have changed yet. Doing the good tests Michael has provided, it almost sounds like you do have a bad alternator. And since this is your second alternator, maybe two bad ones, including a recent rebuild??? I find that slightly hard to believe, but clearly possible.
I would try going back one step further than Michael’s test. Remove all the wires from the back of the alternator. Be sure they do not touch anything. Connect one temporary wire directly from the battery positive to Alternator Bat+. Connect another temporary wire from the Alternator frame to the battery negative post. Start the engine and connect a third wire from the alternator F- post to the alternator frame or battery negative. Check the alternator voltage with a volt meter between the Alternator Bat+ and the Alternator frame (negative.) As you know by now, the voltage should rise over 14 volts. Hopefully it will, and if so, stop before it gets too high, not over 15 volts.
And do check the alternator belt. It needs to be tight and not glazed. And the alternator pulley needs to be tight. There have been cases that both have prevented proper charging.
Tom, thank you for theses detailed instructions.
You are perfectly right, I’m still frustrated. Particularly because this test showed the same result. No voltage from the alternator.
I can’t believe I received a non working unit.
