Total shutdown with elect power suging and fried fusible link
 

Arrgggh.

Hi all,

She left me stranded today. Total power loss, then 3 short surges then dead.

Yesterday, the dash telltales said battery, brake, abs similar to the last time I had to replace my alternator and battery. Would illuminate at startup and would disapper after rpm climbed. Slight whining coming from alt pulley area. Also yesterday I would get an intermittent airbag light.

After cold startup this morning, car idled down to normal 600ish rpm when it got off the bypass air, but then would kick back up to high idle randomly. Defrosters, lights, radio was on/running at the time. Car ran normally for about 20 miles and then the show was over.

Fusible link terminals actually "fused" themselves to the fuseblock. Wire is broken, so hopefully the rest of the system is okay.

Surges were crazy, blower motor at max, all lights, stereo. the whole event lasted about 3 seconds. Then nothing. Had to work the shift interlock to get it on the tow truck.

What happened? Alternator blew? Positive terminal short? How does one remove the pins now welded into the fuse block? Do I get a new link and solder it to the now permanent pins to check fixes?

Any help is greatly appreciated.

Thanks

Re: Total shutdown with elect power suging and fried fusible link
 

Gee Mac you have some problems.:(

This one is the voltage regulator in the alt that has lost control of the voltage. All the lights that came on first were the first signs, as the voltage rose above 15V. When you started the engine in the morning the current changing the battery got high enough to blow the fusible link. Unfortunately The link only protects the battery, the rest of the electrical system is still connected. The alt keeps charging the rest of the electrical system to cause damage.

Depending on what was working at the time, and how high the voltage was, as to how much damage was done to the units, like ABS, ECU, TCU and all the relays that were on at the time.

Harvey.

Re: Total shutdown with elect power suging and fried fusible link
 

Sadly, these seem to be popping up a bit more often the couple years. Harvey, is it just a matter of the alternators and regulators nearing 20 years old or is there something more than that?

Re: Total shutdown with elect power suging and fried fusible link
 

Well that, and the fact that the alt is mounted at the top of the engine shroded by the hood padding, that covers the vents to cool it, so when you turn the engine off, it gets a big heat soak into it, to cook the wiring and the reg.

Harvey.

Re: Total shutdown with elect power suging and fried fusible link
 

Is the regulator built into the alternator?

Re: Total shutdown with elect power suging and fried fusible link
 

Yes it is.

Re: Total shutdown with elect power suging and fried fusible link
 

Quick update,

New (probably crappy reman) alternator in place and fusible link replaced = blow ignition fuse over and over again when turning key to start.

Indicative of anything in particular? Short to ground somewhere?

Thanks

Re: Total shutdown with elect power suging and fried fusible link
 

It may be a slow process, of removing all the fuses, under the hood, then putting them in one by one, checking if the short is still there. That can tell which circuit the short is on.
Start with the slow-blow fuses in the un/hood box. The big square ones.
Do you have the WSM?

Harvey.

Re: Total shutdown with elect power suging and fried fusible link
 

Harvey,
Does WSM mean service manual?

When cranking, fusible link gets hot and no start as it eventually blows the fuse.
I am wondering if the ECU is toasted dark.

Lights, wipers, climate, cruise switch and radio all working. Battery tests okay, voltage wise.
Doesn't the ignition fuse also do the restraint system. Is that why I had the random airbag light? Maybe a seperate issue.

Also new alt is a Bosch 95 amp. Tried to check codes but no light and I'm sure they were all erased.

Hope this helps narrow things.


Thanks

Re: Total shutdown with elect power suging and fried fusible link
 

If you can answer these , it will help.

Harvey.

Re: Total shutdown with elect power suging and fried fusible link
 

Harvey,

Thanks. Have not seen the power light.

Fuse that blows is the ignition fuse. Have not run tests on ECU yet. Will try that or try to find another ECU.

Re: Total shutdown with elect power suging and fried fusible link
 

Yes that looks likely. Fuse16 feeds the ECU, but also the fuel pump relay, that would have been closed when the surge happened.
So If the fuel pump won't run, even with another ECU have a look at that.

Harvey.

Re: Total shutdown with elect power suging and fried fusible link
 

If this is happening more and more, it begs the question: what's a good prevention?

(I don't want to hijack, so maybe a post in "how to"?)

Re: Total shutdown with elect power suging and fried fusible link
 

Replace your alternator....
the regulator is internal and is what causes this. So there is no prevention.

Re: Total shutdown with elect power suging and fried fusible link
 

That was the exact motivation behind my question about the regulator above. Contemplating picking up a maniac alternator for the built engine. But they are a wee bit pricey...

Re: Total shutdown with elect power suging and fried fusible link
 

We can't prevent the regulator from failing. :eek:, but we can prevent it from destroying a lot of electrical components in the process.

If you look in this thread, at post 15, it shows how to reconnect the alternator wiring to prevent this trouble. Post 27 explains why it happens.
http://www.subaru-svx.net/forum/showthread.php?t=49727

It is not a difficult job to do, but good insurance.


Harvey.

Re: Total shutdown with elect power suging and fried fusible link
 

So basically what you're saying is that I need to put another 100+ amp fuse on the alternator output? Here is what my wiring currently looks like: http://www.subaru-svx.net/forum/showthread.php?t=58723

Re: Total shutdown with elect power suging and fried fusible link
 

.

Its the new alternator wiring modification in the How-To Documents HERE

The two wires that were shortened were originally joined together at the alternator post, all that had to be done was to remove them from the alternator post, shorten them and connect them together.

This restores the original circuitry and its inherent safety elements, but excludes the original alternator output, which now has its own dedicated, fused line to the battery.

Implementing this modification is easy, safe and removes and isolates the alternator output from the rest of the electrical system. As it seems that the voltage regulator within the alternator is the weak link and is most prone to go bad, most would want to guard against it. This does exactly that.

This modification had been in place on my 96 Polo since February, 2010 with zero problems.

.

Re: Total shutdown with elect power suging and fried fusible link
 

ECU/TCU on the way. Will test and report back.

Thanks for the help.

Re: Total shutdown with elect power suging and fried fusible link
 

Sounds good. If the pump doesn't run go for the relay.

Harvey.

Re: Total shutdown with elect power suging and fried fusible link
 

A great diagnostic and how-to thread. I look forward to a successful closure.
Gene

Re: Total shutdown with elect power suging and fried fusible link
 

Okay sad news,

ECU replaced and ignition fuse pops when key is switched the on position. Even before cranking. Fusible link stays good.


What next? Ground issue somewhere? :confused:

Re: Total shutdown with elect power suging and fried fusible link
 

Is the ignition fuse connecting the starter and ignition switch? Is it worth looking into the switch?

Re: Total shutdown with elect power suging and fried fusible link
 

As I said before, "Yes that looks likely. Fuse16 feeds the ECU, but also the fuel pump relay, that would have been closed when the surge happened.
So If the fuel pump won't run, even with another ECU have a look at that."

If you can find the pump relay, (don't know where it hides,) and unplug it to see if that is the problem.

Harvey.

Re: Total shutdown with elect power suging and fried fusible link
 

John, I think this needs its own thread. Macs problem has not been resolved yet.:cool:

Harvey.

Re: Total shutdown with elect power suging and fried fusible link
 

Harvey,

As per your previous suggestions:

1. Tried unhooking the fuel pump relay (both relays, not sure which is the fuel pump) under the dash attached to the steering column which still popped fuse 16 when ignition switched to ON position. So no joy there.

2. All fuses out of underhood box. Replaced one at a time until interior ignition fuse #16 popped.

It appears that SBF #4 slow blow fuse #4 is the circuit the fault is on. The SBF's themselves are not blown.

Also to mention that the car will crank even though fuse 16 is blown. All accessories still work. Wipers, climate, radio, windows, hazards, etc.

The quick connect to the alt voltage regulator has two wires that both look like they had gotten pretty hot.

Hope this info helps to narrow things down.

Thanks,

Re: Total shutdown with elect power suging and fried fusible link
 

Mac I see in the Supplementary book for the 95, that the Fuse 16 also feeds the Air bag system. So if you can unplug the Air bag control unit, then see if the short has gone.
I don't know much about the wiring for the Air bag system, but it does warn to "disconnect the Neg battery terminal for 20 seconds before doing anything to the Air bag system.

Harvey.

Re: Total shutdown with elect power suging and fried fusible link
 

So that you do not keep using up fuses, connect a 12 volt bulb in place of the fuse. If with the ignition ON, there is a short circuit the bulb will light up. If you clear the short the lamp will go out. Do you have one of those cheap test lamps with probes?

Regarding fuse 16:

The ignition coils are supplied via fuse 16. Disconnect the grey colored 8 pin plug B4 from socket E3 which you will find on top of the engine towards the rear and connected to a lead running through the bulkhead. See if the short circuit remains.

http://www.subaru-svx.net/forum/atta...1&d=1363505285



http://www.subaru-svx.net/forum/atta...3505390http://


http://www.subaru-svx.net/forum/atta...1&d=1363505600



Are there any aftermarket accessories which have been added to the car, and which only operate when the ignition is turned on? Is there any wiring left in place which could have been left over from an accessory which has been removed and which could be shorting?


In my past experience, when everything electrically was working as it should and then a problem or symptoms suddenly appears, think back to the last thing that you did before the problem occurred. I have undone a mod or two and the problem went away.

.

Re: Total shutdown with elect power suging and fried fusible link
 

Okay, will check for errant accessory wires and try the B4 E3 disconnect.

What is on the slow blow fuse #4 circuit?

Will also try disconnecting all airbag related devices to see if it is in there. Disconnect both battery leads for 10 minutes first? I think I read that somewhere.

Thanks,

Re: Total shutdown with elect power suging and fried fusible link
 

SB fuse 4 supplies all the ignition circuits.
So if you can tell if the short happens on which of the three positions;
When the key is turned to Acc
Or when turned to ignition ON.
Or when you turn the key for the starter to work.
We can look at those circuits.

Harvey.

Re: Total shutdown with elect power suging and fried fusible link
 

Fuse SBF-4, supplies fuse number 16, so that you need to only check items connected after fuse 16.

There is no need to disconnect battery for 10 minutes, as a simple direct short circuit is what you are looking for.

.

Re: Total shutdown with elect power suging and fried fusible link
 

The book specifically states that " before trouble shooting on Airbag system, turn ignition switch "OFF" , disconnect battery ground cable and then wait at least 20 seconds "

I would follow the advice.:rolleyes:

Harvey.

Re: Total shutdown with elect power suging and fried fusible link
 

I actually had a manic alternator that had the regulator go bad after less than 60 days. Blew out my headlights and tail lights. My dash lit up like an Xmas tree and I figured my alternator belt had broken. Was surprised to see 18.5volts on multimeter. Manic will replace for free but my car is my daily driver and they did not even have cores in stock. I was told I needed to wait 2 weeks or more. So my $160 alternator became a $30 core at orielly.

Re: Total shutdown with elect power suging and fried fusible link
 

Harvey,

The short is happening when key is switched to ON or START position. Short is not occuring in the ACC position.

Will try to run some more checks today.

Thanks,

Re: Total shutdown with elect power suging and fried fusible link
 

Spent some time trying a few more thing to narrow things down.


1. Removed B4 harness connector. Still popped fuse 16 when key switched to ON position.

2. Removed steering column shroud and disconnected yellow airbag connector. Still popped fuse 16 when key switched to ON position.


---The only time fuse 16 won't blow in the key ON position is when SBF 4 is removed from the underhood panel.---

Other info:
1. Accessory lights function fine.

2.Voltage regulator wires are cooked. See Pic.

3. Ignition key cylinder is very loose on the security screws. Does it need to be seated tight to ground properly?


Is it worth disassembling the underhood fuse panel to see if connections for SBF 4 and fusible link are damaged?

Not sure what to do next.

Thanks,

Re: Total shutdown with elect power suging and fried fusible link
 

.

Those regulator plug wires show signs of some serious arcing. Not sure if this has an external cause or from within the alternator.

http://www.subaru-svx.net/forum/atta...1&d=1363818901
.

Re: Total shutdown with elect power suging and fried fusible link
 

Further thoughts on my last post

Does the fuse blow when the alternator connector is removed as shown? If it does,check the wire for a short circuit remaining somewhere along the wire or where it terminates.
Are they completely insulated from each other?

If the fuse does not blow with the plug removed the short shown must be within the alternator.

The ignition switch being loose could mean a short here because the wires could be tangled and shorting. If the alternator plug check proves nothing check the ignition switch.


NOTE: If you remove the lower panel under the steering wheel and the steering column covers you will be able to see the two security bolts. If they are loose, you cannot tighten them too much or the heads will shear off and make them difficult to remove. They are designed to do this

Pick up 2 replacement allen-head bolts, 8-1.25 metric, at the hardware store. They have about .75" grip length. The heads of the bolts won't quite fit down in the recessed hole on the ignition switch. You can grind off a little metal around the outside of the heads with the grinder. You can also leave the heads riding on top of the ignition switch housing. It works fine either way. They can then be tightened down securely.


Procedure for removing what you need to gain access to the ignition switch can be found in this thread HERE. Read the beginning of the thread, the actual procedure is in post 6.

.

Re: Total shutdown with elect power suging and fried fusible link
 

As far as I can see, the SBF4 feeds fuse 16, that feeds;
The ECU, TCU, FUEL RELAY, MAIN RELAY, AIR BAG, IGNITION COILS. Also lights on the dashpanel. I can't see anything that uses that fuse.

As you have disconnected the Fuel relay, Main relay, replaced the TCU, ECU, Disconnected the Ignition coils (B4) and the Air Bag power (yellow B58), but it is still there.

The wiring to the Reg has been damaged, but I don't see it causing a problem.
The back of the loose Ign switch may cause a short, maybe?

As there could be a number of units that are shorted, it would be worth disconnecting all those units at the same time, to see if it is still there, to only leave melted wiring as a cause.

Harvey.

Re: Total shutdown with elect power suging and fried fusible link
 

Reading back over this thread, I see that only the ECU has been replaced, mentioned in post 22. There is no mention of having replaced the TCU. Has this been done?

Unplug the TCU and test for fuse 16 blowing with the TCU disconnected. Even if replaced, the replacement could be faulty as could the replacement ECU which should also be disconnected for testing. At this stage in the problem, nothing can be left to chance.

I'm still hoping that the problem lies in the ignition switch/ alternator.

.

Re: Total shutdown with elect power suging and fried fusible link
 

Where is the emoticon for the "forehead slapper"? I didn't think to try with the fried volt reg plug unhooked. I guess this will do.... I am a :tard:

ECU and TCU were both replaced. Will try unhooking them all and also addressing the loose ignition cylinder.

I will also closely examine all wiring and grounds associated with alternator. They all seem pretty heat hardened.

Thanks for your continued support.