engine and drivetrain tii Alternator question

[net30]

Just got my 73 tii back from Regan Seegraves after a lengthy restoration - car came out beautiful. Got the car off the transporter (JP Logistics) and it started right up, no warning lights. Since the battery was out of the car for a few months during the restoration it was nearly dead & died 2 days later. Installed a new Optima Red top and car fired up instantly but now I have the red charging light on while the engine is running....solid red, no brighter while reving engine. Looked at the alternator as a first cause and found the following taped up loose clip and broken (brown ground?)/unattached blue D+? connections. Years ago PO installed a new 45 amp alternator with internal voltage regulator. I also have an uninstalled rebuilt tii alternator that has been bench tested and is good. Don't know if I should re-install the tii alternator and it's harness? After waiting so many months to get the car back I'm jonesing & need a fix of speed. Any thoughts?

[AceAndrew]

If I'm not mistaken that red light can also be indicative of low brake fluid. Have you checked there yet?

[Mike Self]

the one on the instrument cluster's surface; the alternator light is inside the combi instrument that contains the temp and gas gauges.

Connect a jumper ground wire from the alternator to the engine block and see if the light goes out. If so, make up a permanent ground wire. 2002 alternators need an external ground wire to function properly, and 2002s need a two wire battery ground cable--the large cable grounds to the block, the smaller one to the body.

cheers

mike

[mihajlo]

Some things to check:

1) With the car running at idle, connect a voltmeter / multi meter to the battery. Report your value.

2) With the car running at 2500 RPM, get the same reading, and report your value.

3) With the car running, again with voltmeter, measure the output of the alternator, report your value. This is the B+ terminal and is covered by a protective boot on the stock tii alternator.

These are just preliminary checks, which can be done with a tool that is readily available. Whether or not your alternator is truly bad will depend on further diagnosis, but take these measurements first.

[Preyupy]

That is an "Internally regulated" alternator from a later car (320i or later) you can tell by the black box attached to the back of the alt case. That is the regulator and contact brushes. It looks like they did not hook up the wires for the charging light either. It might actually be charging but you need to check everything. The big black connector is for the stock wiring and remote voltage regulator that is not being used right now. There is nothing wrong with using that alt, they work great but you do need to modify the wiring a bit to make them work correctly.

[jgerock]

Just got my 73 tii back from Regan Seegraves after a lengthy restoration - car came out beautiful.

Sorry for your troubles with the tii - but please tell us about the "restoration". Was it just the body, because that wiring is scary along with all the washers used to space the different alternator to the tii mounting bracket.

[net30]

After a little more digging I found that the D+ blue wire was not connected to the back of the alternator. Plugged it on and red charging light turned off!

Here's what I've got........

IDLE = +12.71

2500rpm = +12.85

output of alternator = +13.62

[mihajlo]

You are getting regulated output from your alternator - good. You may be able to get by with these values. Measure the resistance of the B+ to positive battery cable connection and physically inspect the cable condition. Clean the connection points if necessary. And measure your voltage levels at idle and 2500 RPM again. Just as a precaution, visually inspect your battery ground cable (two grounding points: one on body and one on block) and alternator ground cable.

When you have your key in the ignition 'On' position (not cranking, just to the point where you hear the fuel pump humming), are both red lights in the dash cluster ('O' and 'L') illuminated solid?