Alternator issues?

rickeolis · 11-11-2003, 08:31 AM

OK, I have had my car on the road for about a month now, runs decent, but I don't think the alternator is charging. Last night the lights were dim and it barely cranked over, but did finally at the grocery store. This happened once last week too, and I figured that was just a small glitch until last night's issue. I have a brand new battery in it.
I have converted the system over to the 2.7 engine using that motor's electronics including the newer relay pack that is mounted on the left hand electronics plate in the engien bay. I know that this engine has an alternator and not the generator that my 2.0 liter had. I worked well for the former owner, and there was little to converting it as the harnesses stayed the same for the plug-ins to the relay.
I was told NOT to pull the battery cable on this engine while the engine is running because it will fry electronics, so how do I diagnose this problem?

Rot 911 · 11-11-2003, 08:40 AM

If you plan on doing your own work on your car invest in a multimeter! One from Sears (digital) for around $50 will do all you need. Once you have it you can easily see what your voltage is at the battery with the engine off (should be around 12.5volts) and at 1000 rpm (should be around 14volts.

rickeolis · 11-11-2003, 08:55 AM

I got a nice multimeter that has helped me a lot with this conversion. I will try that test, thanks.

I let my battery trickle charge last night so it should be up fully again now.

304065 · 11-16-2003, 06:52 PM

Rick,

It seems like there are always a couple current threads about alternator issues, you might seach under "alternator" and check out a few of them to get up to speed on the issues others have been having.

Fortunately your car came equipped from the factory with a built-in diagnostic tool, the dash warning light!

You charged your battery and it measures 12+ volts at the battery terminals. Good start. Now:

1. When you turn the key on but don't start the motor, what is the light doing? Is it glowing brightly, or is it out?

2. If it's glowing brightly, the problem could be in your voltage regulator or alternator.

3. If it's OUT, the problem is in your wiring, probably behind the oil pressure gauge (don't know if you have the S gauge or the T but it's the same gauge where the bulb mounts). Remove the gauge carefully without dinging up the dash- I don't know whether 69's had the gauge bolted in or not (hmmm, you could check on a technical BBS for that!) but you want to verify that you have a good bulb. One side of the bulb holder should be a red wire with black stripe and the other side should be a blue wire. Do NOT pull the gauge out too far and do NOT replace it if you see any signs of frayed, burned or melted wires or any loose connectors hanging around, you can burn the car down!

You want the bulb to come on brightly when the key is on with the car not running and to go out when you start the car.

Let us know what's happening and we can go to the next step.

rickeolis · 11-16-2003, 09:17 PM

Thanks so much John. This is what I've got: The light does not come on. I have the black wire with the purple stripes (in the engine bay) that the schematic says is the wire that goes to the guage matched to the all black wire from the alternator, this too is supposed to be the right way.

Last week I put the black\purple wire straight to a 12v+ lead and the light in the guage still didn't come on...

This was to be my project today, but then our dishwasher gave up the ghost and I replaced it with a new one and that took up most of the daylight hours.

So, the first thing I need to try is to see if the light bulb in the guage is burnt out or not.

I will keep you guys posted on this, I really appreciate the support!

304065 · 11-17-2003, 07:26 AM

Quote:

The light does not come on. I have the black wire with the purple stripes (in the engine bay) that the schematic says is the wire that goes to the guage matched to the all black wire from the alternator, this too is supposed to be the right way.

You're looking at the wrong gauge. The one you want is to the left- the black/purple goes to the tacho.

OK, the colors for the earlier cars are a little different, but looking at the old diagram, you should have a blue wire coming into one side of the bulb. The other terminal of the bulb holder should be a blue wire with a yellow stripe.

That's on the gauge. When you pull the gauge to check the bulb make sure those wires are correctly connected.

The wire that goes to the gauge is the BLUE wire. It runs back to the voltage regulator, goes in and comes out as a red wire.

In the back, you should have FOUR wires coming from the voltage regulator- a brown (ground) a red with white stripe (Battery Positive) a solid red (D+/61) and a Black (DF, or dynamo field).

The black wire with purple stripes is the signal lead for your tach that comes off the coil (same as in the later cars).

Hope that helps.

rickeolis · 11-17-2003, 10:34 AM

Holy cra&! You're right, that's what I get when I try to address too many things at once. I did do that wrong... Thanks, I will try the blue wire next! As soon as I saw your reply, I remembered that.

I need to get a newer tach for this project (I ran an ad in the classifieds here.)

As far as the DF, D-, and D+ go, I was able to maintain the same wiring harness from the new engine, and was given the new module that it plugged into as well. So I am thinking that the Blue wire coming from the light on the guage should go into the DF Black wire to work according to the schematic.

304065 · 11-17-2003, 10:50 AM

Let me see if I understand you correctly. When you converted to the 2.7, you also unplugged the old electrical console from your '69, and attached the new console? Did it have a 14-pin connector?

The blue wire goes all the way to the alternator, it does not turn into the black wire. The black wire starts at the voltage regulator DF pin and continues to the DF connection on the back of the alternator.

rickeolis · 01:01 PM

OK, here it is: http://www.pelicanparts.com/911/911_Parts/Electrical/911_electrical_1973_CIS_Part2.jpg

The blue wire from the idiot light on the oil guage is the one that needs to go into my D+ of the relay on the engine bay.

The 3 prong plug going to the relay (#4) was seperate from the 14 pin plug on the new engine and I didn't need to mess with it.