87 GT died while cruising then finally came back to life (Page 3/3)
Rexgirl JUL 13, 04:30 PM

quote
Originally posted by Patrick:

Okay, this is really weird. I posted a few hours ago that my alternator has been working fine the last 14 months after a single episode of the alternator not charging. Two hours after I posted that, I got in my Formula, turned the key, the engine snapped to life... but the charging light was glowing red and the alternator wasn't charging. Wow, talk about jinxing oneself!

Obviously, I did not continue on my way in the Formula. That is really really weird.



hi Patrick, Intermittent charging from your alternator may be worn brushes sticking in their holder. With your skills, you might want to attempt repairing the alternator yourself, checking the bearings and replacing the brushes, before surrendering it as a core?
Patrick JUL 13, 05:03 PM

quote
Originally posted by Rexgirl:

Intermittent charging from your alternator may be worn brushes sticking in their holder.



That's exactly what I suspected when it first occurred (and started working again) 14 months ago. It's the only plausible explanation... well, other than aliens.

I have my Subie to drive until I rectify the situation, but I thought I might first just "gently" tap the alternator to see if I can persuade the brushes to un-stick again. If worse comes to worse, I have the new alternator sitting here that I bought last year.

[This message has been edited by Patrick (edited 07-13-2022).]

Patrick JUL 13, 07:33 PM

quote
Originally posted by Patrick:

I thought I might first just "gently" tap the alternator to see if I can persuade the brushes to un-stick again.



So I went out to the car, armed with a large screwdriver with a heavy plastic handle (to tap with). But before I tried anything, I figured I'd start the car and see what the voltmeter was showing. The engine started immediately, the red charging light was glowing, and the meter showed about 10 volts... for about two seconds. And then the voltage shot up to the "normal" 14 volts. Problem solved.

I swear I saw something in the distance...
Raydar JUL 13, 08:43 PM
<X>The Truth Is Out There<X>

Edit - I used to have an 88 Firebird. Used essentially the same alternator.
It had a bad connection on the PC board, somewhere near where the connector plugged in. You could flex it, and then it would charge, and then it wouldn't.
This was before I had the knowledge/nerve to dive into an alternator and resolder connections.

[This message has been edited by Raydar (edited 07-13-2022).]

MattK JUL 13, 11:31 PM

quote
Originally posted by Patrick:

What does that actually mean?

An engine "turning over"... is simply an engine being turned over by the starter. It doesn't mean the engine is starting/running.

So when you stated "After about 10-15 attempts the engine turned over", are you saying that you turned the key to the Start position 10-15 times and nothing initially happened... or that the engine turned over but wouldn't start?



The engine would turn on, rpms would reach 1000rpm and it would shut off again after about a second. I turned the key right after it died and again the engine would turn on, reach 1000 rpm and shut off after about a second. I did that about 10 -15 times until finally the engine stayed on and I drove off the street into a parking lot.
MattK JUL 13, 11:35 PM
Also I spoke to my dad since he owned the car prior to me. Said battery is about 3-4 years old and as far as he knows the alternator is stock... Car has 136k on it from '87. I didn't think am alternator could last that long.
theogre JUL 14, 09:02 AM
3-4 year battery can have problems more so if not driving to charge it often. Few days or months old battery can have same problems...
Lead Battery for starting a car work in a Narrow Window of Volts. run under < ~ 11.8 then life drops. way under life like < 10v drops Very fast.

Other batteries are similar. LiIon only last when operate 3 ish to 4.1 or 4.2 depend on how made. And these Hate Trickle Charge and other schemes Lead, NiCD, and NiMH uses to charge that can cause fires or worse on LiIon..

Alt gets nothing, runs 14month then nothing can be iffy side plug or anything internal. Dash light On then at least lamp works and side plug is good for L pin for CS. (B pin for all SI units.)
ArthurPeale JUL 14, 03:43 PM
I've read about - and have experienced - secondary voltage loss. You can see evidence of this when your car is idling. Watch the RPM gauge. Will it suddenly jump, either lower or higher? It won't jump much.

When it's dark, open the deck lid, turn on the car, and watch. You may see occasional blue sparks from the wires. It causes the electrical system to work harder to compensate, frying your ICM over time.

The age of the wires is irrelevant - mine were brand new out of the box and there was a fairly regular jump from the wire to the engine block. Some dielectric grease solved that specific issue.

Ignition coils that have started to break down can also cause this. They'll be fine cold but once things warm up, not so much.
Patrick JUL 15, 03:52 AM

quote
Originally posted by MattK:

The engine would turn on, rpms would reach 1000rpm and it would shut off again after about a second. I turned the key right after it died and again the engine would turn on, reach 1000 rpm and shut off after about a second. I did that about 10 -15 times until finally the engine stayed on and I drove off the street into a parking lot.



As I mentioned way back Here, I still think you should check the fuel pressure... and if nothing else, at least eliminate one variable.

[This message has been edited by Patrick (edited 07-15-2022).]

Patrick SEP 06, 11:52 PM

We never did hear whether or not MattK resolved his issues... but my alternator mystery continues. Two months ago my Formula's alternator "healed" itself after not charging and it's been fine ever since, but today the same nonsense occurred again. I was almost home, and the charge warning light came on. When I pulled up beside my house, I left the engine running, and opened up the decklid so that I could tap the alternator (trying to dislodge potentially stuck brushes). Nothing happened, Charge warning light remained on. If there's no second miracle "recovery" overnight, I'll install the new alternator that's been sitting here for a year and a half. I'll then also take the old alternator apart to see if the brushes are indeed sticking.