M42club.com - Home of the BMW E30/E36 318i/iS
DISCUSSION => Electrical => Topic started by: 92BMW318is on June 20, 2011, 03:41:03 PM
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Replaced alternator with an 105v alternator. went up from an 80v to an 105v.
Replaced battery same as old battery.
Dont know whats causing the battery to not charge.. and the car to die.
Arent cars suppose to be able to run off the alternator alone?
I swear I've heard of it. In that case it could be a bad alternator...
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Are you sure everything was hooked back up properly? There are 2 wires from the main harness that need to be connected, and it is grounded through the engine.
- Alternator body-to-bracket ground cable?
- Engine grounding cable?
- Battery-to-chassis grounding cable?
Does the car start? Does it even turn-over?
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Are you sure everything was hooked back up properly? There are 2 wires from the main harness that need to be connected, and it is grounded through the engine.
- Alternator body-to-bracket ground cable?
- Engine grounding cable?
- Battery-to-chassis grounding cable?
Does the car start? Does it even turn-over?
It started and ran for like a day then on the high way the stock cd player turned off and then turned on and was crackling like there was static or somthing when music was playing. I was like "wtf" and then the dash lights started to get really dim. then i turned off everything. and it drove fine till i got up to the exit and like a mile before the exit the engine started to bog down like it was losing power. so i floored it to 80mph and then pressed in the clutch and coasted up to the exit made a right on red and turned into a gas station. at that point all lights were off and car was completely dead.
My friend happend to be at the gas station at the time, he got jumper cables out and jumped my car from the battery. I started my car then it ran he took the jumpers off and then the car ran for like 5mins then died in idle. soo then we hooked them back up and let it charge for 10mins while my car was off. I quikly drove home, but right before i got to my house (5mins away from the gas station) the same thing started to happen like on the high way. i had to coast the car to the parking lot.
The battery light isnt on and the check engine light was flashing when the car started to die. but after the new alternator was put in it cured(stoped) the battery light and the check engine light from being illuminated. Then check engine light use to be on for like a year prior to the alternator replacement.
Stomp test no longer works on my car for some reason(this has been like this for a year).
Im positive all the connections are hooked up properly.
Im taking the battery up to autozone and getting it tested. If its good then i guess ill have to take the alternator off and get it tested. if both are good then i have no idea wtf is wrong.
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Did you order a new / rebuilt alternator, that included a new voltage regulator?
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With the car on, measure the battery, should reach 13. something I believe. This tells you battery is charging. Check for the spec online, can't recall it. This might tell you battery is not getting a full charge.
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Did you order a new / rebuilt alternator, that included a new voltage regulator?
Yeah it had one in it. ill do the test on the battery while the car is running and tell you guys what i get in the morning its 4am here right now. the alternator i got was a Duralast Rebuilt 105v "Valeo" I seen the volt regulator underneath the plastic case on the back of the alternator before i installed it. but there is no telling if its shit or not.
If the battery isnt getting a charge then ill take the alternator out and get it tested, if its broken I'm going to raise hell at autozone.
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I'll bet that the battery & alternator are OK. It's great that you're getting them tested though, you're eliminating causes one by one. I strongly suspect you have a pretty severe electrical problem to chase down. Granted, they're a pain in the ass, but they're much cheaper than throwing new parts at the car. You'll also get to know that car inside & out doing stuff like this.
If you have a severe short it'll give you those symptoms. The car can't run on the alternator alone unless the electrical system is in excellent shape. I'd guess that the car will set a CEL if voltage is too low...many things in the car must have a little over 12VDC to run properly, especially injectors, coils, etc. All modern ECUs have a voltage correction circuit built-in to handle a discharged battery.
So fire up ye olde old digital multimeter... If you don't have a decent one, I'd highly recommend it. Sears & Radio Shack sell economical ones. You won't need a Fluke. Alternatively, go get two of those $4.99 cheapies at Harbor Freight (they only live a year or two).
My first test is current draw...I charge the battery (it should test to ~12VDC unplugged), install it in the car. Switch the DMM on amps & install it inline right in the middle of the battery - terminal and the -wire. You could use the + side but you have to be careful not to short it on the frame of the car. See how many amps the car is pulling at rest (don't even put the key in yet) maybe 30 seconds after you reconnect the battery...mine usually is about 200-400 mA. Should be less than 1/2 amp (500mA). I then put the key in, turn it to pos II (no fan or stereo) & see how much the car is pulling then. IIRC shouldn't be much more than an amp or two.
So if the car is pulling more than 1/2 amp, get some helpers (kids work great) and have them look for the current to drop while you remove & replace the fuses one by one. When the current drops, you'll have your circuit; then look that circuit up in the ETM & test it out. At that point I'll just leave the fuse out & drive the car a while to see if it's fixed. Keep in mind that there is also an unfused side to the car...the starter, DME and fuse box itself aren't fused so if the "pulling fuses" test didn't do anything your short is likely there. Also keep in mind that early e36's are famous for flooding the DME & pinching brake light wires in the trunk hinge area.
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Thanks Dave I just took the, car up to AdvancedAuto and they did a battery check. the battery measured out as fallows
VOLTAGE: 12.34
MEASURED: 729CCA
RATED: 700CCA
TEMPERATURE: 89F
Then he had me start the car turn on the headlights, radio and the battery read 11.34ish.
I hope this helps, he stated that the alternator wasn't charging the battery. I'm going to go out and test directly from the alternator and see what it says.
I'll post back in a second.
UPdate: Okay back the I tested from the alternator and when the car was on, it said 12.04 turned on all the lights musics heated seats and fan read directly from the alternator again and it said 11.84.
shouldnt i be seeing around 13.00 coming from the alternator.
Im just going to take the damn thing off and take it up there...
UPdate: Okay so i took it off(alternator) and took it to autozone and they bench tested it and It read out that it passed...
now since all else failed im going to go threw all the steps Dave mentioned and see if I can't figure this out.
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Looks like the battery is not getting enough from alternator which could be what Dave state, you have a draw somewhere else. Just start to pull fuses.
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See if you can just swap the voltage regulator form the old one into the new one (not sure if they will be interchangeable). Maybe they put a crap one in the rebuilt one.
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Replacing all the engine ground straps as they are old. replacing with zero gauge ground wire(or somthing along that gauge.)
I let you guys know if this fixes it.
tryed pulling fuses this did nothing
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my e30 did not charge when i drove without instrument cluster. Something to check maybe?
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^ he brings up a good point. You need a cluster as the SI lights can drain battery. Not sure with e36. I believe you have cluster in as you said battery lights have turned on.
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I'm told that pre-facelift e30s did have an older style of charging system; with a burned out battery light the system wouldn't charge. Newer e30s have an parallel resistor wired into the cluster to prevent that from happening. I also don't think the SI board will drain the main battery...it'll just keep the OBC from working correctly.
The alternator won't "break even" until at about 2k RPM, and the battery really doesn't charge until maybe 3k.
You're on the right track. Keep testing & eliminating possible causes. Don't be afraid of a digital multimeter. Sure it's a pain in the ass...but it's not rocket science, just a few wires. Trust me, it'll save you a ton of money. Don't throw parts at it & hope it'll work. Just be careful not to short any really thick wires. If you have to work on really big parts (alt/starter/unfused side) or really small parts (cluster/stereo/OBC) disconnect the battery first.
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I took off the alternator for a third time and took a 1/4 drill bit and drilled a hole threw the bottem tab, attached a ground wire with 1/4 bolt washer and a nut. hooked the other end of the ground to the lower intake bracket (where the manifold bolts down to the subframe.) This is the first thing I did, once I put the alternator back on, I turned over the car and the volt meter read out 13.23ish (use to be 11.84)turned on all the lights radio and heated seats. voltage lowered 12.89 and revved the engine to 2grand a slight pick up occured to around 13.30. Turning her off, disconnecting the battery then I proceeded to replace all other grounds and positives. plus repaired some frayed wires I noticed. and now voltmeter reads out 13.89 when car is at idle and then 14.12ish when at 2grand.
List of everything I replace.
replaced positive lines from alternator to the starter then to the battery added ground wire from alternator to subframe, replaced ground from battery to frame replaced ground from engine to frame. replaced hood and trunk ground strap for the hell of it. butted together frayed wires on fog lights and one on head light covered with heat shrink tubes for weather proofing.
also...
put new ICV on intake to improve idle. ;)
Thank you guys for all your support, and help. With out you guys my car would be toast. I really do appreciate it. :)
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having a similar prob with a 91 318is , although I've been through 2 alternators that have lasted a month each running perfect before the no start, abs lights come on cars dies etc. could I really have bad luck with the alternators or something else. all grounds look clean and solid
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If you have a short in the harness or a low battery it'll slowly kill the alternator. Check the voltage on the battery with the car off, the voltage when the car is idling and the voltage when the car is at ~2500-3000 rpm. The alternator and battery work as a team; if one has a problem they can both be damaged.
Also test continuity or resistance from the alt case to cyl head to ground studs. They all should be virtually 0 ohms. The e30 motor ground strap tends to decay internally - it carries a lot of amps. It's on the driver's side at the motor mount. Check that for resistance if you see anything odd.
Alternatively, take the battery and alt to (at least two) parts stores and get them tested. Those dynamic tests are the most reliable information you can get. They'll do it for free (and sometimes give really good advice).