I know electrical shorts are a pain, but I'm missing something and need a hero.
86 Fiero SE V6 battery went completely dead. Without thinking I bought a new one and got my son out of the bad neighborhood it broke down in.
But the next day the new battery was dead. So I fully charged it and went for a spin. While driving it never really went above 13 volts on the dash gauge and less when I turned anything on. When idling, I checked the voltage across the battery terminals and once it spiked over 14v but mostly stayed between 12 and 13.5v. I also checked the negative cable contact where it bolts to the engine and the smaller wire to the firewall trim but they were secure and clean.
Following the advice from a few different threads on this wonderful resource, I pulled out the multimeter and sure enough there was a 2.86 amp draw instead of less than 50ma. We jammed the door switch, then pulled and reinserted every fuse in the box under the steering wheel but the ammeter stayed between 2.85 and 2.88. I also pulled the single-wire inline fuse at each headlight. I should mention I'm not hearing any clicking at the headlight motors either nor a fuel pump motor. No change. Is there another fuse box I'm missing somewhere?
Now the only thing I have noticed for sure that was working before this incident but not since is the trunk light. I have checked the orange cable at it had like 12.4v when I put it between the meter and ground. Still, the light wouldn't come on but when I disconnected the trunk light assembly and hooked it up directly to the battery with alligator clips the light came on like it should. Which makes me wonder if the second wire (white) to the trunk light, presumably a ground, is working properly.
I've been looking at the electrical schematics online and cannot find the one that shows the trunk light (do you have one??) on it so I'm not sure where to go from here.
The battery is at 12.55v right now. By morning it will be dead. <big sigh>
Thanks in advance for any help!!
[This message has been edited by CenLA (edited 06-15-2014).]
With the battery at full charge, unplug the harness from the oil pressure sending unit and let it sit overnight. You may not hear the fuel pump running.
[This message has been edited by fierofool (edited 06-15-2014).]
With the battery at full charge, unplug the harness from the oil pressure sending unit and let it sit overnight. You may not hear the fuel pump running.
I'll do that right now before I crash for the night. What are you thinking?
BTW, in reference to my trunk light which I *think* is on the same circuit as my power windows and trunk release, they still all work.
I'm not getting any ADSL (or whatever it is) codes other than normal Code 12 (one blink of the SES, pause, two blinks, pause, and repeat) if that helps.
Try unhooking your alternator battery wire. I've had a bad alternator that did this to me.
Me too.
If it's still there after unhooking the alt, the logical answer is the wire going to your starter. Check out the Ogre's Cave (links at the top and bottom of every page) for great help tracking down electrical gremlins. Trust me, I know how frustrating they can be, had to make my wife push me across a Target parking lot to bump start the car once
Originally posted by fastblack: If it's still there after unhooking the alt, the logical answer is the wire going to your starter. Check out the Ogre's Cave (links at the top and bottom of every page) for great help tracking down electrical gremlins. Trust me, I know how frustrating they can be, had to make my wife push me across a Target parking lot to bump start the car once
------------------ Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should. (Jurassic Park)
Referencing the oil pressure sending unit, I had a battery drain on my 86SE. Just happened that one morning the battery was dead. Charged it up and the next morning it was dead. Got a new battery and the next morning, that one was dead. One of our local Fiero mechanics suggested that it was the oil pressure sender. I put a meter on the battery and unplugged the oil pressure sender and the voltage jumped back up.
There's unswitched 12 volts going to the sender. The other two wires feed the oil pressure gauge and fuel pump backup circuit. You may not hear the fuel pump run.
I couldn't figure out how to disconnect the oil sender plug. So I left it for now. I was afraid I'd break it like I did previously on the coolant fan switch.
I went to every plug-type connection I could find on the block or in the engine compartment and tested after each. Still 3.18 amps on average.
Then I disconnected the thick red cable on the back of the alternator and tried it again. It dropped to roughly .28 amps. Does this make the alternator the actual problem or is it just the beginning in a series of steps to getting to another problem?
Ogre, I had already found your page on Google and read it, stopping at the point where is says IF PULLING THE FUSES DOESN'T WORK. I dunno why I stopped there (maybe frustration) but after I went back to it, I started with the alternator and stopped when I got this .28 amp reading which I'm thinking is still way higher than 50mA, right?
The 86 has a rubber cap that just pushes down onto the 3 prongs on the top of the sender. To unplug it, simply pull straight up. Some of those rubber caps have a plastic retainer around them. Find the juncture of the ring where it lathes and open it up. You should then be able to pull the harness up and off the sender.
Unhook one of the battery cables. Put a test light (or any 12v. bulb) between the cable & the battery. If you have a drain, it will light up. Pull each fuse until it goes out - that's the circuit that's draining your battery. ~ Paul aka "Tha Driver"
Originally posted by CenLA: Okay, so here's where I'm at. Does this make the alternator the actual problem or is it just the beginning in a series of steps to getting to another problem?
Looks like you have more than one problem. The alternator has a short inside.....and then you need to find the additional small drain.
Looks like you found it. Replace your alternator with a US made one if you can find it. Most of the Chinese made stuff I've experienced doesn't last long or is already defective when it comes to you over the counter. I hate that. I am more than willing to pay twice as much for a US made automotive product because I don't have to replace it anytime soon. It just lasts. I see this a lot with electronics and bearings.
You should have a normative small drain on your battery from the PCM and your radio.
[This message has been edited by IXSLR8 (edited 06-17-2014).]
As previously stated, you will always have a small drain on the battery.
Before buying a new alternator, be sure to have it tested. If it comes out OK then it's the wire going from the C500 to the alternator (ultimately the problem on my car). If you replace the wire, be sure you leave the fusible link in the section of wire by the C500, do NOT replace it with some sore of in-line fuse. Always use quality connectors too.
Obviously if the alternator is bad it will need replacing. Many will suggest replacing it with one from an 88 since it is better quality. Doing a quick search here or checking out the Ogre's cave again will give you a lot of info on this swap.
[This message has been edited by fastblack (edited 06-17-2014).]
I had a battery drain that I could not find. Out of desperation I took it to my favorite shop. He pulled out the cigarette lighter and the drain stopped.
The cigarette lighter had corroded and puffed up causing a connection through the corrosion. Not a complete connection, just partial.
The scary part is it could have started a fire. Well, maybe not. These cars do not catch fire.
I picked up an Delco-Remy reman alternator at Autozone today for $70.00. I'm still not convinced it's the alternator but I can't see any issue from the thick red cable towards the battery. I will swap it out and see if it fixes it. It's still the only thing that dropped the high amperage when disconnected. I'm assuming if it was the lighter or trunk light that the issue would have gone away when the fuses were pulled, right?
easier said than done. Apparently it is near impossible to remove an alternator out of an 86 SE with automatic transmission. Even with the tie-rod and mud skirting removed I don't see enough room to get it out. Ideas?
easier said than done. Apparently it is near impossible to remove an alternator out of an 86 SE with automatic transmission. Even with the tie-rod and mud skirting removed I don't see enough room to get it out. Ideas?
I would first prove that it is the alternator. Disconnect the battery (+) first. Remove the positive connection from the alternator, then cover the end with electrical tape for safety. Next put an ammeter between the battery cable and positive terminal of the battery. If you still read more than about 20mA, then the alternator is not your problem...no need to change it. If it reads around 20mA, then you have found the problem and can progress with the aggravation of replacing the alternator.
I picked up an Delco-Remy reman alternator at Autozone today for $70.00. I'm still not convinced it's the alternator but I can't see any issue from the thick red cable towards the battery. I will swap it out and see if it fixes it. It's still the only thing that dropped the high amperage when disconnected. I'm assuming if it was the lighter or trunk light that the issue would have gone away when the fuses were pulled, right?
Sorry...looks like you already did test it...if the current draw dropped when it was disconnected, then that should be your problem.
Ahh those pesky automatics, another reason I'm glad to own a 5-speed is for alternator replacement. You're on the right track in taking it out through the wheel well. I've heard of folks taking it out through the top but involved removing the dog bone and some other stuff that seemed like just as much of a hassle as going through the wheel well.
It comes out the wheel well, jacking the car up so the suspension is hanging makes it easier (wheel and liner off) - IIRC, I found that taking it out back side first was easier (if not it was the other way - any event try turning it and taking it out in another direction.
Guys, I want to thank you for your guidance. I believe the problem with the parasitic drain was related to the alternator.
I've changed the last Fiero alternator I will ever change in an automatic V6. What an absolutely horrible design for a part everyone knows is liable to be replaced at some time. After a lot of very loud @$#%$!# I found the only way to remove the alternator was from the bottom through the wheel well. I had to remove the wheel, wheel well skirting, split a tie rod, undo the four bolts supporting the alternator bracket, those funny pipes (what do they do anyway?) between the trunk and the dogbone and a few electrical cables that were in the way.
But it's done and it's working like it should. Thank you all for your assistance. I do appreciate it.
Those "funny pipes" come from a blower motor mounted behind the carpet in the trunk. They are there to "cool" the alternator and coil. IIRC, the blower motor comes on whenever the radiator fan comes on. Most will say they are completely worthless, 88's did not have them.
What an absolutely horrible design for a part everyone knows is liable to be replaced at some time.
Not "liable to be replaced" but "necessary to be replaced". Notice that only an extra 1/2" or so would have made it possible to lift out the top. this is where my "GM is evil" theory comes from
Glad to see you got it solved. Battery drain is the worst.
[This message has been edited by PaulJK (edited 06-23-2014).]
I'm also having a battery drain issue. I'm tacking it onto this post in hopes of some help on a specific point that I've not seen covered before.
The problem started several weeks ago. First noticed it on a Monday morning following a weekend that I did not drive the car. The battery was dead. I jump started it and it was fine all week and the next weekend (when I drove it on that Saturday) and through the folowing week. Then on the following Monday after not driving it Saturday or Sunday it was dead again. I suspect I am having the same issue as described here. A slow battery drain caused by who knows what at this point.
So, for about three weeks now I have been disconnecting the positive battery cable (since it's easier to get to) every nite and reconnecting it in the morning before going off to work. (it's my daily driver) I also disconnect the battery when ever I leave the car for several hours. I disconnect it when I arrive at work and then reconnect when take off for lunch. Then the same when I get back from lunch and then again when off to home.
In all that time I have not had a single instance of a dead battery. Then yesterday after working on the car a bit I cleaned up the ground connection from the battery to the chassis and decided to leave it overnight to see what would happen. No other troubleshooting yet. This morning the battery was dead.
My question is... since I have been disconnecting the battery, and it holds a charge, and the alternator appears to be working OK since the battery must be charging when I drive it, have I sufficiently isolated out both the battery and alternator as a source of the battery drain? ------------------ John Wayne as John Bernard Books in The Shootist... " I won't be wronged. I won't be insulted. I won't be laid a-hand on. I don't do these things to other people, and I require the same from them."
My rides... 1988 GT with a 3.4L V6 automatic 2006 Harley Sportster 'cause I love the twisties on two wheels or four.
[This message has been edited by Rsvl-Rider (edited 09-29-2014).]
One other thing, a battery can fail internally. I had a battery that i took out of the car and set on a bench charged it up full, it would sit there and lose 2 volts a day all by itself. I also had one fail internally so it was only able to be chaged up to 7.5 volts. Both were Autozone batteries, one red top and one yellow top.
Rsvl-Rider....make sure you have a good multimeter when doing electrical testing. You need to be able to measure current and voltage. Read the manual carefully so that you hook it up correctly. The first thing to test is the battery. You can take that into most autoparts stores to be tested....don't assume that the battery is good. A bad battery will damage other parts of your charging system. Once you know the battery is good, then you can test current draw (put the multimeter on the current setting, with the leads in the correct connections on your meter, inline with positive wire from the battery). You should get about 15-20mA with everything shut off. If you have a higher draw than that, then there is a problem. Pull one fuse at a time, until the excess current draw disappears....that will indicate which circuit is bad (just remember that the ECM is drawing current...when you disconnect the fuse to the ECM, the current draw will drop 15-20mA). Then you have to follow the circuit from one end to the other, testing each component / connection / ground on that circuit until you find the problem. You can also have multiple problems...which obviously makes it tougher to find. Just work through everything using the above methodology, slowly and systematically.
Thanks for all the good advice guys but for now I am just looking for an answer to the question I posed a couple of posts up....
Can I safely rule out the battery and alternator based on the following experience...
quote
Originally posted by Rsvl-Rider:
So, for about three weeks now I have been disconnecting the positive battery cable (since it's easier to get to) every nite and reconnecting it in the morning before going off to work. (it's my daily driver) I also disconnect the battery when ever I leave the car for several hours. I disconnect it when I arrive at work and then reconnect when take off for lunch. Then the same when I get back from lunch and then again when off to home.
In all that time I have not had a single instance of a dead battery. Then yesterday after working on the car a bit I cleaned up the ground connection from the battery to the chassis and decided to leave it overnight to see what would happen. No other troubleshooting yet. This morning the battery was dead.
My question is... since I have been disconnecting the battery, and it holds a charge, and the alternator appears to be working OK since the battery must be charging when I drive it, have I sufficiently isolated out both the battery and alternator as a source of the battery drain?
Disconnect your oil pressure sender and see it you have a drain!
Yes, I get that more testing is needed. What I am trying to do is find out if I have successfully eliminated the battery and alternator as potential causes.
Originally posted by Rsvl-Rider: So, for about three weeks now I have been disconnecting the positive battery cable ....I have not had a single instance of a dead battery. Then yesterday after working on the car a bit I cleaned up the ground connection from the battery to the chassis and decided to leave it overnight to see what would happen. No other troubleshooting yet. This morning the battery was dead.
I assume the positive cable was hooked up as well as the negative the night after you cleaned the neg connection?
If there is a circumstance where the battery does not drain, the battery is good.
So the question is does disconnecting only the positive battery cable overnight and not getting a drain prove the alternator is not the drain?
I assume the positive cable was hooked up as well as the negative the night after you cleaned the neg connection?
If there is a circumstance where the battery does not drain, the battery is good.
So the question is does disconnecting only the positive battery cable overnight and not getting a drain prove the alternator is not the drain?
Yep, After I cleaned up the ground the battery was completely reconnected overnight. The next morning the battery was dead
There has never been a battery drain when the positive cable was disconnected. It started and drove fine every time after reconnecting the battery. And since the battery always had enough charge to strongly fire it right up over those couple of weeks where I was disconnecting the battery overnight I would think that would indicate the alternator is good too. Just trying to confirm these thought before I go chasing all the possible gremlins.
Yes, I get that more testing is needed. What I am trying to do is find out if I have successfully eliminated the battery and alternator as potential causes.
lets try again.
battery stays charged when battery is disconnected. = BATTERY IS GOOD!
Battery is drained or lost power when left connected = Alternator could be the problem. More testing needed.
88 use CS130 alt but rest is same to look for Battery Leaches
also CS Alternator CS doesn't die and drain the battery like many others but still need to check.
Best is get small DC Amp Clamp meter so don't need to unplug or cut wires. Quick example: https://www.amazon.com/Uni-...itance/dp/B00O1Q2HOQ w/ 2 to 100 DCA Is first listing found, others could be used here but Bigger clamps have issues reading under ~ 5 to 10A.
Note: Most Amp Clamps are AC Amps only and won't work.
