Grounding Issue?

[Bwana]

I've started to get the red "alternator" light to glow slightly after the engine starts up (Italian '72 CSi). I can't see it in the daylight but I can if I'm in a parking garage or if it's dark outside. It glows a little brighter when I turn on the headlights but definitely NOT as bright if, for example, I've had an alternator failure or when I get the "check lights" just proir to starting the engine.

The car runs a little rough too, almost like surging from the FI system. I've heard the D-Jet systems are very sensitive to ground issues so possibly clue #2?

Where would be the first/most likely place to start checking?

 

[abe3.0CSi]

I had the exact same problem with the alternator light. I replaced the regulator...no difference. I replaced the alternator and resolved the problem. It may be a diode and not producing a full voltage.
Also, replacing the battery not made a difference. Sooo, assuming all your connections and ground is fine...I put my money in the alternator.
abe

 

[Bwana]

Sigh....exactly what my mechanic said. How much are these things going for these days? I called around to a couple of auto-electric shops a couple of months ago because I had the alternator out for other reasons but nobody rebuilds them anymore, their comments were that it's cheaper to buy new.

Does NAPA or Autozone carry them or do I have to go to a BMW aftermarket place?

 

[HB Chris]

Tons available on eBay, upgrade to an internally regulated Alt with more Amps. I used bnrparts and got an 80A one for around $100, bolted right in but you may need to swap your pulley over. HTH.

 

[JhwShark]

Try autozone or napa...keep your mounting bracket and pulley. The newer pulley's may be different in its size and may be offset to far making the belt rub...

Also try an ASE (Alternator Starter Exchange) shop; check phone book, they may have one and/or will rebuild yours. I picked up a Starter recently for an old Porsche.
DELCO has a variety of models and you may just need a suitable bracket and pulley...

Confirm your voltage and output...
Bat voltage at rest
Bat voltage once started
What is the v output at 1500rpm?

Jon

 

[61porsche]

Altenator

Bwana,

Napa shows them ( Bosch). O Rielly has a remanufactured unit for $52. I believe N. Houston has a BAP Geon. ( The main store is on Scott and 45S just past downtown) They've been around forever. Take it to them as most places still check them for you; if it's just the ext.regulator burned out you might get lucky to change that out.

There are electrical rebuilders in Houston. If you need one of them, PM me and I'll hunt the info down. A lot of older restored porsches around use the rebuilders for originality if that's what you want.

NAPA shows they have the parts if you've done it yourself before and the armature isn't toast. ( Brushes, diodes, etc.)

Watch the Pully though as HB and others have noted. It's close between the power steering pump belt and the alt. belt.

The only other difference and thing to watch for is wether your altenator uses bushes ( plastic sleeves where the bolts run through for mounting ) or not. Mine doesn't and I was expecting that it did. I didn't have any play either in the fit.


61Porsche

 

[61porsche]

Glowing charging light

Bwana,

There is a point that rpms and altenator charging turn off the light.( My E9 does this rarely until the carbs/chokes kick in or I press the gas) If the engine is missing or running rough as you describe and the rpms are down it's possible you need to attend to that. ( rpms below 800?) If the light goes out after you raise the rpms or blip the throttle you're set. If it happens at speed; somethings amiss and it's generally the external regulator unless something got crossed by mistake. Since as you say it happens with the lights on , it could be load related. Very faint glow to slightly brighter?

Old cars have old wiring and resistance can build up even if the wires / connections look good.( Especially for us since we live with 100% humidity in Houston) Clean the connections at the alt. and battery. If you've got 13v or more at the battery it's not the altenator.

Of course, if you're running big loads with amps and a/c, etc. you'll probably want to upgrade as HB says to be on the safe side. I run two amps and a/c and haven't seen that problem yet, but I guess I just jinxed that by talking about it.

I still have a 6V Porsche and they're notorious for the glowing red light syndrome ( Nothing wrong other than built up resistance) and bad connections. Some guys just live with it.

If you've got good voltage and it's just the lamp- let me know as there is a fix for that too. If you changed the guage lights to LEDs, it won't draw enough to turn it off either; but you didn't mention that.

I've not heard that BMW ECU's are terribly sensitive to voltage. But there are others here on the board with far more FI experience than me that can help.

61Porsche

 

[pamp]

Ground

I ended up running a 12 ga. ground wire from the battery to the ECU where the ground wire for the fuel pump is located after the car died and no fuel. Pump was fine but wanted the extra ground...so be it!

 

[Bwana]

Update

I've removed the alternator and have it up at an auto-electric shop I found in Conroe. Should get it back tomorrow. Cost for a complete overhaul including all electrical checks, new bearings and brushes is about $75.

Hopefully will solve the problem.

Thanks for all the help! Will update when re-installed

 

[Bwana]

Ate up with the dumba$$

Can I say that?

Well, alternator was fine. Long story short, I think it was a loose wire from the alt. to the regulator. Doh! I noticed the nut seemed a little loose when I took it off. When I put it back together I made sure everything was tight. Car now runs great, about 13.8 V charg=ing voltage.

Thank for all the suggestions though, now I know what to look for next time (hopefully NOT a next time)

 

[nathanegger]

Was hoping someone was around still from this old thread. Got car back from paint shop and I have an open circuit or ground. Nothing when I turn key. New battery and all dash lights stay on when I pull the key?
Help[emoji2955][emoji2955]


Sent from my iPhone using Tapatalk

 

[sfdon]

Was hoping someone was around still from this old thread. Got car back from paint shop and I have an open circuit or ground. Nothing when I turn key. New battery and all dash lights stay on when I pull the key?
Help[emoji2955][emoji2955]


Sent from my iPhone using Tapatalk

Do a voltage check in your fuse box. Check at fuses 6 and 7
Then remove 6 and 7 fuses and check top of 6 and 7 fuse holder
Then check green wire at back of ignition switch for voltage with key off.

 

[sfdon]

Sounds like you are bleeding positive voltage from ignition switch or alternator.

 

[Ohmess]

Just to clarify something on Don's test -- parts of our fuse blocks act as power distribution. Unswitched power -- fuses 6 & 7 are joined together at the top of the back of the fuse block so as to distribute unswitched power. This means if you do the test Don describes you need to pull both 6 & 7 in order to get proper results. If you pull 6 and then test, put 6 back in and pull 7 etc., your results will not be correct.

 

[sfdon]

Excellent! Thank you.
Yes common bus on top of 6/7

 

[Bwana]

FI or carbs?

 

[sfdon]

Pull your hazard switch connector off the hazard switch. Do the lights go out on your dash?
(Alt and oil pressure)

 

[nathanegger]

Pull your hazard switch connector off the hazard switch. Do the lights go out on your dash?
(Alt and oil pressure)

No sir may I have another.


Sent from my iPhone using Tapatalk

 

[nathanegger]

Carbs


Sent from my iPhone using Tapatalk

 

[nathanegger]

Ok not sure if I did it right but I get nothing on 6 and 12 on 7?


Sent from my iPhone using Tapatalk