So, I installed a ground wire from a stud on the intake to the ground on the trunk lift... Come out a few hours later to a dead battery!

What's the deal- IIRC, this 'shouldn't drain my battery. Any ideas?

This is an 85 V6.

there is no on/off switch in the ground side
so no extra ground can drain a battery
you have short in the hot side

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Question wonder and be wierd
are you kind?

The most common cause would be worn headlight motors.But there are other causes,like a bad pin switch causeing the courtesy lights to stay on.A brake pedal switch that is out of alignment causeing your brake lights to stay on 24-7.A bad alternater (look at your gage above the center console,it should read about half way while the engine is running).A stuck fan relay causeing the fan to run 24-7.Trunk light on.The leading cause for a major power drain is the headlight motors.Allso have your battery tested,maybe its shot.Improperly installed electronics,such as an amp would allso cause a major power drain (if you did something like this recentley).

Sorry, let me rephrase.

I had NO battery drain before I added this. Thus, it is not a bad battery, bad lights, bad motors, or anything else. Somewhere the hot side of the battery is shorting into the engine block. Thus, grounding the engine block causes the battery to drain.

What could cause that?

I added a wire from an intake stud to ground. Battery drain. Cut it off, no battery drain.

Bump?

Thats a new one to me....I cant explain what would do that ! Especially considering your motor is or should be grounded in a couple places allready.

Sorry no answer for you

quote Originally posted by AspenGrey: Sorry, let me rephrase. I had NO battery drain before I added this. Thus, it is not a bad battery, bad lights, bad motors, or anything else. Somewhere the hot side of the battery is shorting into the engine block. Thus, grounding the engine block causes the battery to drain. What could cause that? I added a wire from an intake stud to ground. Battery drain. Cut it off, no battery drain.

You had insufficient ground prior to installing a good ground thus completeing a usable circiut for what ever is draining your battery. Whatever is draining your battery just showed you that you need to do some more work. The new ground is providing a better path for the power drain. That is actually good news, now go through and clean up the remaining grounds, negative battery cables, straps and connections.

After you complete that work, disconnect your positive battery cable from the battery and then complete the circiut with an idiot light. Since you have a power drain it should glow, go through and start pulling fuses until the light goes out, that's the circiut that you need to look at. Remember that the ECM and radio will draw a little power as well as a courtesy light from an open door. Speaking about courtesy lights, GM wired them hot to 2 different circiuts, a useful tidbit of information in your search for the power drain.

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jetman
Silver 86 SE 2M6 4-speed, with "check wallet light"
Now fortified with 8 essential slices of bacon goodness

quote Originally posted by AspenGrey: ... it is not a bad battery, bad lights, bad motors, or anything else. Somewhere the hot side of the battery is shorting into the engine block. Thus, grounding the engine block causes the battery to drain.

Not possible. There were already multiple ground connections on the engine block before you started. If you are accurately telling us the whole story, all you did was to add one more ground path to those already present, nothing else.

I understand your frustration, but you ask for help, people here are trying to provide it, and you respond by arguing with them. You assume that the problem isn't "a bad battery;" you assume that it isn't "bad lights;" you assume that it isn't "bad motors;" you assume that it isn't "anything else." Have you actually tested the battery or measured the current drain on any of these circuits? There is no substitute for hard data.

As others have suggested, in a Fiero the headlight motor circuits, lights remaining on when they should be off, and a bad alternator are the three most likely suspects.

[This message has been edited by Marvin McInnis (edited 07-18-2009).]

Interesting. if adding that wire caused the problem, then it would appear that you either don;t have an engine ground now, or you grounded something along the way.
If I were to trouble shoot this, I would try like this:
Remove BOTH battery connections.
Take a meter set on ohms, low scale, and measure from a clean good spot on the block to the negative battery cable end. expect to see no more than 1 or 2 ohms. Now measure to the positive battery terminal. you should see an open, or over 1000 ohms. if you still see a short, then it;s time to start hunting down the problem.
Now if the neg is high, as in over 10 ohms to the block, you don;t have a good ground, and the strap you added did not cause the problem but just showed up an existing problem that was masked by your bad grounds.
I suspect that you have bad grounds now that masked a problem.
I would next reinstall your good ground. Verify that the neg battery cable is now down to under 2 ohms to the block, if not, you have a bad cable to the block from the battery, or a bad connection. you should be seeing it also thru the small black wire that goes to the strut tower. I would disconnect that cable and verify it is good, as if the main ned cable to the block went bad, that wirre usually opens.
Once you repair any issues foune and can confirm that the block is now measuring under 2 ohms to the cable and frame, move on to diagnosing where your short on the positive side is.
You can isolate at the c500 connection, and drop the heavy wire from the stud on the alternator. that should just leave the heavy cable to the starter and depending on the year one or 2 links on that stud at the starter.
Basically, fix the bad ground issue then go find your drain, a number of threads on isolating are there, basically you can use an ammeter with the + to the battery and neg to the cable, and start removing connections until you loose the drain. A typical car with radio and ecu should be 20 ma, no more than 40ma. I quick kill llike you saw is likely drawing over an amp, so be careful your meter can handle it. if it cannot, use a light bulb in series form the + cable to the battery+, those small 196 marker bulbs are great for that. any glow is a problem.
Good luck!
you can go end to end with an ohmmeter and verify that the cable shows under 1 ohm. ( you may have to clean the contacts for a good test)

quote Originally posted by tjm4fun: I suspect that you have bad grounds now that masked a problem.

Exactly, that's what I thought too. If the grounds are bad enough, theres no way for a bad head light motor (or whatever) to drain the battery since there's no path back to the battery. It's just like disconnecting the negative battery cable to prevent a drain.

In reality you have more than one problem, bad grounds, a parasitic electrical drain on the battery and maybe more.

If the car worked before, even so much as a dome light could turn on, adding that ground did nothing. The ONLY way adding that could have changed anything was if there was no connection to the battery before.

What actually happened? Probably you left the radio on, maybe left the door open too long while working on it, or if your trunk light works you could have left the trunk open overnight or something. The last place to look is that grounding strap, unless of course you hooked it to the positive terminal lol.

So I would charge the battery and take a decent bet it will be fine. If it goes down again, look closely at anything you touched since it worked last.

Heres what I did:
Added a ground from manifold stud to ground. Battery is drained 2 hours later (no other work done)
Jumped the car, drove around. (Assumed that I had drained it while cleaning the car with the radio on)
Car is dead again the next morning. I jumped the car, CUT the new ground ,and drove to work. Car was fine 8 hours later. I took the battery to be deep-cycled after work. No problems reported, no problems with draining battery since then. Obviously, something is leaking current directly into the engine block. I doubt thats a bad headlamp motor. That said, I checked everything after the Fiero get-togethor this afternoon. The reason I assumed it was none of these things is because after I cut the ground it no longer happened.

Why I know it isnt a bad battery, bad dome light, bad headlamp, etc.

Battery was tested when I had it charged after it was drained. I had them test the alternator for kicks while I was there.

The headlamp motors do not get warm, click, hum, or draw a current when tested with a multimeter.

The dome lights are not on, or broken in any way I can tell. A multimeter shows no drain


TJM- thank you for the helpful post. I'll work on those things tomorrow.
I _know_ that a simple ground shouldnt cause this, what I was looking for was something like TJM's post that suggested things that could logically be draining through the engine block.

The car runs great without that strap, but it raised serious concerns because of the drain. Another V6 at the Get-togethor had added the same ground (same location) and had had the same problem, his is running great too. 0.o I asked all the other people htere, noone could think of a reason why that ground would have caused a drain.

I did do a bit of my own testing before this... and the car IS working fine, I drove it about 200 miles today with absolutely no problems (that I didnt already know... damn ball joints))

The negative battery cable on the battery, bolts right to the rear head. There is already a path from the block to the battery. What you are adding it completely redundant. Cutting the strap has to be coencidental to the 'fix'

Also, you should never deep cycle a standard car battery, its very bad for them.

quote Originally posted by 86GT3.4DOHC: The negative battery cable on the battery, bolts right to the rear head. There is already a path from the block to the battery. What you are adding it completely redundant. Cutting the strap has to be coencidental to the 'fix' Also, you should never deep cycle a standard car battery, its very bad for them.

Well, a deep-cycle charge is what the manufacturer of my battery tells the auto shop to do. It's not like im using a self-charger, this is a computerized charger and tester at Checker's and I've had batteries charged this way for years and never had problems... So I'll stick that way.

I'll add the strap back tomorrow and see if I suddenly have a load on the battery, as that's the only thing I didn't check. (Not wanting to risk having a dead battery when I needed the car running for a date) I'll leave it there and see if it drains again if I dont have a load. I know right now there is only a tiny, tiny, tiny load on the battery when the car is off.

Edit: That may not be a true 'deep-cylcle' charge. But thats what they told me to ask for and so that's what I do. I give it to them and come back an hour and a half later to pick itup (or a few times to get a new battery... 36 month warranty FTW.)
Question: Would the engine even run with the battery to block ground missing? Furhtermore, would it run quite well (with the eexception of running rich enough to result in 14-15mpg, although since I cant trust my odometer right now (speedo is stuck at either -10 or 46 until the car gets hot, either by running for a while or sitting out in the sun) Im not sure if its really getting that much. An Air/fuel gauge is in the priceline)...

[This message has been edited by AspenGrey (edited 07-19-2009).]

This is most interesting.

The negative battery cable on the battery that bolts right to the head is grounding the engine. By adding that extra ground wire (intake to the ground on the trunk lift) you're grounding engine to frame. If that is causing a battery drain, why isn't the factory stock main flexible grounding strap from head bolt (engine) to deck lid (frame/chasis) not causing a drain?

Did you check resistance in all of the grounds with your meter?

(-)Braided block to deck lid body ground.
(-)Trans to frame body ground.
(-)Battery to battery tray body ground.

Might be worth it to recreate the difficulty by adding the extra ground again and testing the current draw with the meter to issolate the problem area?

You also mentioned that you had the alternator tested but I'm wondering if you don't have a flakey diode that escaped the testing.

edited early Sunday morning for clarity.

[This message has been edited by jetman (edited 07-19-2009).]

quote Originally posted by jetman: This is most interesting. The negative battery cable on the battery that bolts right to the head is grounding the engine. By adding that extra ground wire (intake to the ground on the trunk lift) you're grounding engine to frame. If that is causing a battery drain, why isn't the factory stock main flexible grounding strap from head bolt (engine) to deck lid (frame/chasis) not causing a drain? Did you check resistance in all of the grounds with your meter? (-)Braided block to deck lid body ground. (-)Trans to frame body ground. (-)Battery to battery tray body ground. Might be worth it to recreate the difficulty by adding the extra ground again and testing the current draw with the meter to issolate the problem area? You also mentioned that you had the alternator tested but I'm wondering if you don't have a flakey diode that escaped the testing. edited early Sunday morning for clarity.

Jetman- thanks for the extra suggestions, I'll test these too.

ok. let's clarify, a ground is a ground. engine ground must equal frame ground. there are at least 3 points I can say that tie these together.
1. battery negative to strut tower ground, small wire. ties directly to the heavy ground to the head.
2. braided strap from the engine to the decklid support.
3. all of the 3 seperate gorund connections on the rear foward head and the bell housing to the ecm and to the tunnel sheetmetal just foward of the ecm under the console.
all those grounds must be common, and are unless there are some major issues.

quote Originally posted by tjm4fun: ok. let's clarify, a ground is a ground. engine ground must equal frame ground. there are at least 3 points I can say that tie these together. 1. battery negative to strut tower ground, small wire. ties directly to the heavy ground to the head. 2. braided strap from the engine to the decklid support. 3. all of the 3 seperate gorund connections on the rear foward head and the bell housing to the ecm and to the tunnel sheetmetal just foward of the ecm under the console. all those grounds must be common, and are unless there are some major issues.

Unfortunately i was in denver all day today... DIdnt get a chance to do any tests. I'm seriously weirded out by this.

quote Originally posted by AspenGrey: So, I installed a ground wire from a stud on the intake to the ground on the trunk lift... Come out a few hours later to a dead battery! What's the deal- IIRC, this 'shouldn't drain my battery. Any ideas? This is an 85 V6.

As mentioned before,a ground strap does not cause a battery drain-period-unless it has a power/positive source directly connected (low resistance) to it.

What is near the trunk lift?
If the trunk lift were motorized I would say check the actuator for a short to ground-that possibly had a poor/high resistance ground till your ground strap was added.
Your looking for something odd like that.
If that were the case,then an existing short actually had an open circuit on it. Adding the ground strap would technically be a short on an open due to a short. Not an easy one to diagnose..

The people suggesting an existing unknown issue was brought to light by your modification is not farfetched at all.
Added grounds on a vehicle do it no harm,and if you beleive Nology and the ricer's they actually will add horsepower by stabilizing your charging system.

Is there a trunk light nearby that hasn't worked in a long time? maybe the glovebox light has always been a problem and a little finicky?
The power to it could be in the same harness as some engine ground's to the engine area,maybe one of their power wires shorted on a common ground wire. This would short the component that belong to that power wire,but not necessarily cause detrimental effects to whatever is attached to the common ground always.
Then you add a ground that the failed circuit could short to with less resistance so now you have a parasitic loss.


On older vehicles with high mileage you can't rule out anything.
Including the battery,even if it's new-get it checked. If it's from Wal-mart,just buy a new one(not from walmart).
In electrical,everything is a variable.
Get comfortable with a multimeter,or drop it off at a good mechanic that understands electrical systems.
Most mechanics still test for voltage with a test light,they are hacks and don't let them touch your car.

Hope this is helpful,someone already gave a starting step by step for easy diagnosis of the issue-if I can be any help plz let me know.
I'm a dealership tech specializing in electrical and drivability.
I don't always know the answer,but willing to help both of us learn.


(This situation brings to mind the most recent,and only hard,battery drain issue i've really ever had. Intermittent drain,it would pull 3A in millisecond bursts every few minutes in no particular pattern,with peak's in the 5-7A range. The crazy pattern was indicative of a module drain,except they don't pull high amperage. Took me 3 days and somehow blew up my $450 multimeter to find out it was the alternator-and that was after I just decided to starting unplugging harness as I had already been through 2 entire fusebox remove/install's tracing ghosts.
Everything's a variable with electricity )

quote Originally posted by DefEddie: As mentioned before,a ground strap does not cause a battery drain-period-unless it has a power/positive source directly connected (low resistance) to it. What is near the trunk lift? If the trunk lift were motorized I would say check the actuator for a short to ground-that possibly had a poor/high resistance ground till your ground strap was added. Your looking for something odd like that. If that were the case,then an existing short actually had an open circuit on it. Adding the ground strap would technically be a short on an open due to a short. Not an easy one to diagnose.. The people suggesting an existing unknown issue was brought to light by your modification is not farfetched at all. Added grounds on a vehicle do it no harm,and if you beleive Nology and the ricer's they actually will add horsepower by stabilizing your charging system. Is there a trunk light nearby that hasn't worked in a long time? maybe the glovebox light has always been a problem and a little finicky? The power to it could be in the same harness as some engine ground's to the engine area,maybe one of their power wires shorted on a common ground wire. This would short the component that belong to that power wire,but not necessarily cause detrimental effects to whatever is attached to the common ground always. Then you add a ground that the failed circuit could short to with less resistance so now you have a parasitic loss. On older vehicles with high mileage you can't rule out anything. Including the battery,even if it's new-get it checked. If it's from Wal-mart,just buy a new one(not from walmart). In electrical,everything is a variable. Get comfortable with a multimeter,or drop it off at a good mechanic that understands electrical systems. Most mechanics still test for voltage with a test light,they are hacks and don't let them touch your car. Hope this is helpful,someone already gave a starting step by step for easy diagnosis of the issue-if I can be any help plz let me know. I'm a dealership tech specializing in electrical and drivability. I don't always know the answer,but willing to help both of us learn. (This situation brings to mind the most recent,and only hard,battery drain issue i've really ever had. Intermittent drain,it would pull 3A in millisecond bursts every few minutes in no particular pattern,with peak's in the 5-7A range. The crazy pattern was indicative of a module drain,except they don't pull high amperage. Took me 3 days and somehow blew up my $450 multimeter to find out it was the alternator-and that was after I just decided to starting unplugging harness as I had already been through 2 entire fusebox remove/install's tracing ghosts. Everything's a variable with electricity )

I'll stick with some of the other ideas first... But thanks for the advice. As I said the alternator (and diode) and battery were checked. It's an AUtpower Gold Series battery from Checkers.

wait a min here. You just described several possible electircal issues in a post that are there. Your speedo not working til car gets hot??? are you sure theres to electriacl short there that eat expansion is chaning the short? Poor fuel milage? Sensors out of range with wires chaffed touching your block? In your first post you say the car runs great no issues now you say that you have speedo malfunctions and possible poor fuel milage. As posted above i agree to check factory grounds to see if there operating but the more you go it sounds like you have other issues that need adressing.

Can anyone post a PIC of where the ecm ground is supposed to attach to the bell housing ? Thanks

quote Originally posted by Tstang429: wait a min here. You just described several possible electircal issues in a post that are there. Your speedo not working til car gets hot??? are you sure theres to electriacl short there that eat expansion is chaning the short? Poor fuel milage? Sensors out of range with wires chaffed touching your block? In your first post you say the car runs great no issues now you say that you have speedo malfunctions and possible poor fuel milage. As posted above i agree to check factory grounds to see if there operating but the more you go it sounds like you have other issues that need adressing.

The difference being I know what these two issues are- the O2 sensor is out of range and just needs to be replaced, and the VSS is shorting internally -- tested these to my satisfaction a while ago.

Edit: Im not 'totally' ruling anything out except the battery being dead .Everything WILL get checked, Im just planning on starting with more logical things, and NOT things I've very recently tested. (Within the last 3 or 4 weeks. When I first got the car I went through 2 dead batteries and some dead sensors. I also had a short from cruise control wiring and some sensor wiring that has been repaired or replace- resoldered & heat-shrunk insulation)

[This message has been edited by AspenGrey (edited 07-20-2009).]

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