Spyder Possible alternator problem

rolltidero · Nov 13, 2014

So I know this is another thread about alternators and I know this topic has been beat to hell but I can't find any circumstances like mine. So over a weekend I got red LEDs to put in my interior for gauges and hvac. I installed them and they lit up fine my doors were open for hours with the interior lights on. I figured my battery would be low so I took it out for a drive about 10 minutes went by and my brake and battery lights came on. My alternator died on my while drivig before so I immediately went home. When I got home I immediately started researching what could cause this. I tested my battery and it read 4 volts so I charged it overnight and the next morning it had 14. Put it back in and again about 10 minutes of driving and the lights were on again. Everything pointed to my alternator but both my alternator and battery are about 15 months old. Upon further inspection of my car I noticed my negative battery terminal was a bit loose and the top plug on my ecu was a little loose from where I took my hvac out, I fixed both of those charged my battery and still dummy lights. I've read before that LEDs can cause a battery to drain but I'm not sure. I know alternators are known to randomly go but I just want to be 100% sure.

NHerron · Nov 19, 2014

DSM1G90 said:
.. The power supply(ies) that runs LEDs can be a power hog.

That's inacurate. General purpose LEDs should never be power hogs, and why would there be a 'power supply'. You mean + & - 12v leads and a resistor? However some LEDs like the whole Cree q4 business can draw quite a current, but their efficiency and output is also high.

I'd put my money somewhere else.

rolltidero · Nov 19, 2014

NHerron said:
That's inacurate. General purpose LEDs should never be power hogs, and why would there be a 'power supply'. You mean + & - 12v leads and a resistor? However some LEDs like the whole Cree q4 business can draw quite a current, but their efficiency and output is also high.

I'd put my money somewhere else.

I was only wondering because before I put the lights in there was no problem then after I got them in the alternator was crap. I know I have a small oil leak that has been dripping around the alternator for a month or 2. I'm thinking that maybe having the car sit for 3 or 4 days with oil on it maybe fried it.

DSM1G90 · Nov 19, 2014

Yep..oil or any form of sludge getting into the alternator causes early death to the unit.

rolltidero · Nov 19, 2014

DSM1G90 said:
Yep..oil or any form of sludge getting into the alternator causes early death to the unit.

Is there anything else charging system related that I need to check? I've read battery light, generator relay, and g terminal ground in ecu. The last one I don't know how to check exactly but my ecu was unplugged while installing the LEDs.

NHerron · Nov 19, 2014

Well you said something about the battery light, so the fuse powering both the L and S terminals (red wire and black/yellow wire) is good. Also covers the connection to alt because the light comes on, (alt grounds the bulb). Red wire could be cut somewhere but even if, the black yellow wire is its backup.

Only other thing is the fusible link for the alt output. With engine running, ground one lead of your meter (voltmeter/DVOM, you have one right) to the alt body, and other lead goes to the 10mm but holding the two white cables. If its above battery voltage then obviously fuse is bad and alt is trying to charge.

G terminal:
http://www.dsmtalk.com/forums/archive/index.php/t-83589.html

Why'd you disconnect ecu for led install?

rolltidero · Nov 19, 2014

NHerron said:
Well you said something about the battery light, so the fuse powering both the L and S terminals (red wire and black/yellow wire) is good. Also covers the connection to alt because the light comes on, (alt grounds the bulb). Red wire could be cut somewhere but even if, the black yellow wire is its backup.

Only other thing is the fusible link for the alt output. With engine running, ground one lead of your meter (voltmeter/DVOM, you have one right) to the alt body, and other lead goes to the 10mm but holding the two white cables. If its above battery voltage then obviously fuse is bad and alt is trying to charge.

G terminal:
http://www.dsmtalk.com/forums/archive/index.php/t-83589.html

Why'd you disconnect ecu for led install?

I had to take the hvac out and I unplugged the ECU and unbolted it so I could move it around to get to the hvac cable that is right above it. It was just for ease of access to the hvac cable

DSM1G90 · Nov 20, 2014

Had that 80A issue one time and with the same "no-charge" thing: looking at it, it looked good in the fuse window, but took the fuse out and did the VOM thing and it was open.

A connection at the base of the fuse where the links attach to the mounts inside the fuse had opened up.

Went to a yard and tagged a few 80A fuses from all the Mitsu vehicles out there - buck a fuse.

Got back on the road after the fix

DSM.

rolltidero · Nov 20, 2014

DSM1G90 said:
Had that 80A issue one time and with the same "no-charge" thing: looking at it, it looked good in the fuse window, but took the fuse out and did the VOM thing and it was open.

A connection at the base of the fuse where the links attach to the mounts inside the fuse had opened up.

Went to a yard and tagged a few 80A fuses from all the Mitsu vehicles out there - buck a fuse.

Got back on the road after the fix

DSM.

I already got a new 100A fuse and replaced it. Are you saying there could still be something wrong where the fuse gets bolted in?

NHerron · Nov 20, 2014

A simple available voltage check is all that's needed.

$5 gets you a good one, 90% people don't know how to fully use a basic DMM, let alone one over $100. The common cheap digital ones are great, and if you don't like the reading you get, you can chuck that sob across the room for fun.

rolltidero · Nov 20, 2014

NHerron said:
A simple available voltage check is all that's needed.

$5 gets you a good one, 90% people don't know how to fully use a basic DMM, let alone one over $100. The common cheap digital ones are great, and if you don't like the reading you get, you can chuck that sob across the room for fun.

Yea I have one of the cheap free ones from Harbor Freight that seems to work great

DSM1G90 · Nov 21, 2014

..

.. and I still have the swing needle analog one ... which I use when doing ECU code readings.

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Spyder Possible alternator problem

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