Today I found that I have a parasitic draw. And a pretty bad one at that, 250 mah. I tested by hooking up a multimeter and pulling fuses. The problem is, none of the fuses were causing the draw. I pulled each and every fuse underneath the dash, as well as the dingy thing and the two other relays in the "convenience center" under the passenger side dash. I am totally at a loss for how to find this draw now. I read that there was another fuse box behind the battery, but all I found was a big electrical connector and a couple of terminals. How can I find this draw?
------------------ 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)
Original radio? Some aftermarket alarm/immobiliser systems installed? Checked a known circuit to see if meter is showing correct values?
Not original radio, but very similar OEM GM radio. Pulled the fuse on that and no change. No other aftermarket things installed. Fairly certain the meter is right, as the car does die when sitting, but I'll double check.
Sometimes radios are installed unfused at all by mysterious "previous owners". So I would pull the whole radio out just to be sure as the fuse that powers it might not be the one you think.
Situations like these are easier with a low-current clamp meter. Something like this but it is pretty expensive if you only will use it once...
Sometimes radios are installed unfused at all by mysterious "previous owners". So I would pull the whole radio out just to be sure as the fuse that powers it might not be the one you think.
Situations like these are easier with a low-current clamp meter. Something like this but it is pretty expensive if you only will use it once...
Meanwhile I've pulled the headlight and dimmer switches, no problem. Pulled another relay that was in the engine bay on the drivers side fierwall. Not sure what it was, but it wasn't the problem. Pulled the backup light switch, nope. pulled the IAC connector... no issue. etc. I've just been pulling whatever I can find. I found that when I pull the top small stud off of the block behind the battery, my draw dissapears. But as far as I can tell, the only thing that eliminates is the starter.
Fusable Link B is mostly headlight motors and switch. They are often the problem, so you may want to see if you missed something there. Other items on A are the heater fan relay and the radiator fan relay.
I have less than 10mA draw on my '85 duke when nothing's running. Then again 250mA after 24h is "only" 6Ah, so that should not totally kill your battery unless sitting for approximately a week (if you have a good 50+Ah battery).
Just disconnecting the one wire blue connector does NOT disconnect the motors from the battery. It only prevents them from going up, but they are still powered.
[This message has been edited by cebix (edited 03-05-2017).]
So I'm thinking... I know that if I start the car and only run it for a few minutes, so it doesn't warm up, then shut it off, the fuel pump keeps running for a couple seconds. Could the relay be causing my parasitic draw? I know it runs without the car in run for a few seconds on cold shut down, so that kinda makes sense, right?
The only problem is I don't know where to find the relay for the fuel pump. could anyone point me to where it is?
Another thought - maybe the 250mA you see is intermittent. Sounds like it could be the headlight motors thermal switch.
Do you have arcing when you put on the negative battery terminal on? If you open up the front hood can you hear the motors "clicking" from time to time by themselves? Are they warm?
I have less than 10mA draw on my '85 duke when nothing's running. Then again 250mA after 24h is "only" 6Ah, so that should not totally kill your battery unless sitting for approximately a week (if you have a good 50+Ah battery).
Just disconnecting the one wire blue connector does NOT disconnect the motors from the battery. It only prevents them from going up, but they are still powered.
It doesn't totally kill the battery, but the car doesn't have enough power to start. It'll crank slowly a little bit and then stop.
I was not aware of that with the motor wires. Does disconnecting the relays disconnect them fully? I did do that. If not, I'll have to figure out where to disconnect those.
If you really pulled ALL the fuses and the current was still there...
The only originally further unfused circuits under fusible link B are the headlight motors. Are you sure you pulled the motor relays and not just the isolation relay?
How are you actually measuring the amps?
[This message has been edited by cebix (edited 03-05-2017).]
Have you tried swapping in another (known to be good) battery and testing for amp draw? Have you had a draw down test on your battery? Walmart does it for free. Has your battery ever been frozen before? This can bend plates and short out cells.
Case in point.. I unwittingly put a AAA battery in my pant pocket. A while later I felt something like a bee sting on the side of my leg but there was no bee. Lesson learned, even a AAA battery can short out when you have a pocket full of change.
Spoon
------------------ "Kilgore Trout once wrote a short story which was a dialogue between two pieces of yeast. They were discussing the possible purposes of life as they ate sugar and suffocated in their own excrement. Because of their limited intelligence, they never came close to guessing that they were making champagne." - Kurt Vonnegut
I also have a later model Pontiac firebird GM radio with CD player. The radios have two power connections. One is always on and the other is with the key. My radio was drawing .250A with the key off. Since the car sits for weeks at a time the battery was getting low from sitting. Pull the radio to make sure someone did not run the always on power connection around the fuse box,
I also have a later model Pontiac firebird GM radio with CD player. The radios have two power connections. One is always on and the other is with the key. My radio was drawing .250A with the key off. Since the car sits for weeks at a time the battery was getting low from sitting. Pull the radio to make sure someone did not run the always on power connection around the fuse box,
Correct. There is an orange wire to the BAT fuse and a yellow wire to the RADIO fuse.....(or there should be.)
If you really pulled ALL the fuses and the current was still there...
The only originally further unfused circuits under fusible link B are the headlight motors. Are you sure you pulled the motor relays and not just the isolation relay?
How are you actually measuring the amps?
I am not sure. I pulled the relays right next to the headlight buckets, I"ll have to check and make sure I'm not missing the motor ones.
As for the battery, it has been load tested. Several times. It is still good, or so say the guys at the parts store.
As for the radio, I did totally pull that out and got no change.
I did pull each and every fuse, but I did it one at a time. I did not test it with no fuses in at all, though I was watching the current while pulling fuses so I don't think it would make any difference.
Are the relays right next to the headlight buckets the correct ones? Or should I be looking elsewhere?
Originally posted by I_N_J: Nope, not the starter. So now I've disconnected everything that I've been able to find and haven't had any results... I'm totally lost.
Okay, so according to that fierocave link "You should have no more than 250 ma (milliamps) with just the ECM and radio memory draw."
I have right at 250ma, but that really seems high to me, and I know that my car dies when sitting for a day.
Have you tested the Battery? 250ma is 1/4 amp and shouldn't kill the battery in a day.
Could be 250ma quote has typo errors... (That cave page is archived and won't be fixed.)
quote
we suggest a 25-milliamp draw is normal and anything that exceeds 100-milliamps indicates an electrical issue that needs to be addressed.
You remove allot and still have same isn't ECM and others.
AC/DC amp clamp meter can save a lot of time but maybe too small to register... If you have wire... loop around the arm when open then read. looping can add more amps the meter reads so don't freakout.
Do you have arcing when you put on the negative battery terminal on? If you open up the front hood can you hear the motors "clicking" from time to time by themselves? Are they warm?
Any more on what causes the arcing?
------------------ 86 SE Convertible 3800sc 4t65e HD(2002), Gen V, 3.3 pulley, SD headers
Sorry for the late response, I've been pretty busy.
To my knowledge the battery is good. I haven't personally load tested it, but I did have it load tested several times at an auto parts store.
I'm testing amps by removing the positive battery cable, then setting my multimeter to amps and touching one contact to the battery terminal and one to the cable.
Sorry for the late response, I've been pretty busy.
To my knowledge the battery is good. I haven't personally load tested it, but I did have it load tested several times at an auto parts store.
I'm testing amps by removing the positive battery cable, then setting my multimeter to amps and touching one contact to the battery terminal and one to the cable.
Just experienced a similar problem on my wife's car. Her battery would drain overnight to the point where the engine would not turn over in the morning. It was a repetitive problem that happened 4 days in a row. There was a current draw but it could not be isolated UNTIL I checked the battery. Measuring across the negative terminal and the battery surface and I was getting a voltage of about 8V. What was happening was that there was current pathway between the terminals caused by acid over spill from the battery . Thoroughly cleaned the battery top with a water and baking soda wash , then dried it with paper towels. No more voltage measurements on the battery top and the car has started up each morning with no further issues.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
Originally posted by I_N_J: To my knowledge the battery is good. I haven't personally load tested it, but I did have it load tested several times at an auto parts store.
Simple load test often fails to find many battery problems.
Test it w/ computer test. Does more than load test.
Repeatedly drain the battery so can't start can weaken or kill it quick.
Some further ideas for you to try.. You are correct to disconnect the wire and put the amp meter in series with the wire. Make sure that you note the difference between amps, milli-amps, and micro-amps on your meter. You measured current on the battery wire. Is it possible to get separate measurements on the fuse links on their current draw? When you put the meter on the battery wire, can you turn on one thing, such as dome light, and get a sensible reading on it?
Simple load test often fails to find many battery problems.
Test it w/ computer test. Does more than load test.
Repeatedly drain the battery so can't start can weaken or kill it quick.
Unfortunately I don't have the resources to do this.
I'm beginning to revert back to my original theory of battery problems though, and here's why...
I haven't been able to try any of the other suggested tests, as I've needed to drive the car this week, so I've just been driving around with a self-jumper pack. Today I noticed something... I got home from work at around 6 last night, and went to start the car this morning at around 9:30. I put it in run, and looked at the voltage gauge that I put in there. It was giving me a solid 12 volts. I tried starting it. It slowly cranked before giving up, but the voltage was still at around 10 volts at that point. I threw on the jumper pack, and put it back in run and looked at the gauge. It was exactly where the battery had been. 12 volts on the money, and yet, when I pushed the key this time, it started right up. So the battery has got the voltage, but it's not putting out the amperage to turn over.
Don't get me wrong, I am not even close to an expert electrically, but the battery was still at 12 volts this morning, yet the car would not start.
Would anyone else care to interpret these symptoms? I haven't checked on that parasitic draw lately, but were it the cause of my issues, shouldn't the battery have lost voltage overnight?
battery right after engine running will have 13+v. full charge = 12.6-13v for most. up to ~13.5 for some.
Battery can be "dead" @ 12v and more so when one cell is bad. (12v battery have 6 2.1v cells) Give away is 10v after attempt to start... Means at least 1 cell is bad.
I just replaced battery in my UPS for computer. 12v battery so bad got hot and puts out <3v.
