electrical question.

[pong]

my engine dies when i turn on all the electrical components in the car

at idle, test 9, battery voltage i think
indicates approximately 13.4-13.6

when i turn on the aircon, this drops to around
12.5 - 12.8

when headlights are on, this drops to 12.1 - 12.2

when i engage the gear, it goes down to
11.7 and then, it cuts out...

i placed a tester on the battery, the results indicate a
voltage of 13.5 and does not change,

what could possibly be wrong here?

[Ferret]

Sounds like your alternator is about to go to the great scrapyard in the sky, it's producing a meagre voltage and not enough current.

First though, have your battery load checked by someone, if it's on its way out it may produce similar results.

Could be your wiring/battery terminals though - check those first!

[pong]

the battery is relatively new

negative cable from battery is new,
positive, still have not changed it

where are the grounding points located?
i could not find them, i only saw one that is near the battery.

thanks

[whiskychaser]

Mine only gets run about once a week now as I walk to work! So I dont expect the battery to be in great shape. Just checked it out of curiosity and I got these voltage figures on a cold engine:

Idle: 13.95-14.01
+ A/C (fan has to be on low) and headlights: 13.95-14.01
+ A/C, headlights, heated rear screen: 13.85-13.95
+A/C, headlights, heated screen, in 'D' (foot on brake): 13.85-13.95

Looks like the voltage drop you have is killing the motor. I'd be looking at the alternator output as suggested. Some places will check it (and the battery) for free as they want to sell you one! I'd also have a look at the fusible links

[Ferret]

Mine only gets run about once a week now as I walk to work! So I dont expect the battery to be in great shape. Just checked it out of curiosity and I got these voltage figures on a cold engine:

Idle: 13.95-14.01
+ A/C (fan has to be on low) and headlights: 13.95-14.01
+ A/C, headlights, heated rear screen: 13.85-13.95
+A/C, headlights, heated screen, in 'D' (foot on brake): 13.85-13.95

Looks like the voltage drop you have is killing the motor. I'd be looking at the alternator output as suggested. Some places will check it (and the battery) for free as they want to sell you one! I'd also have a look at the fusible links

Now you've said that, it could possibly be the engine is idling too low and not spinning the alt faster... is it idling smoothly or is it rough? Do M20's have an adjustable idle air bypass on them, I cant remember?

[shogun]

for my car this helped:

changed the voltage regulator to a new one, the brushes of the old one were almost gone. Still have some of the good ones from Hella on stock F/S under for sale.
Fits on Bosch alternators.

and, also very important: this wire I replaced
http://twrite.org/shogunnew/fixes/electricalpower.html

since then no more probs.

[pong]

without a/c and everything else, im idling at roughly 900-100 rpm...

then as i start to increase the loads, it starts going down...


where are all the fusible links that i need to check?

i changed all the old fuses already, could be loose or something and
since its cheap... might as well change them...

[whiskychaser]

without a/c and everything else, im idling at roughly 900-100 rpm...

then as i start to increase the loads, it starts going down...


where are all the fusible links that i need to check?

i changed all the old fuses already, could be loose or something and
since its cheap... might as well change them...

Mine only idles at about 700rpm but it certainly does not go down when I switch anything on. In fact, the idle goes up slightly when you put the a/c on - as it should do. It sounds more and more like your alternator isnt giving you the power you need. You can replace the brushes/resistor pack if its faulty. Fusible links are here:
http://www.bmwe34.net/E34main/Maintenance/Electrical/Fusible_link.htm

[Ferret]

for my car this helped:

changed the voltage regulator to a new one, the brushes of the old one were almost gone. Still have some of the good ones from Hella on stock F/S under for sale.
Fits on Bosch alternators.

and, also very important: this wire I replaced
http://twrite.org/shogunnew/fixes/electricalpower.html

since then no more probs.

Hmm, I've heard this may affect E31s too, I shall have to investigate!
May also be after a regulator from you too, as my alternator doesnt cope well under full load atm.

[pong]

with regards to the voltage regulator, where exactly is the voltage regulator of and e34, my version has the battery in the front. is it inside the box containing the ecu?

[bmwrp8]

with regards to the voltage regulator, where exactly is the voltage regulator of and e34, my version has the battery in the front. is it inside the box containing the ecu?

you have to take your alt.out of the engine. it is in the back of the alt. http://www.realoem.com/bmw/showparts.do?model=HC21&mospid=47373&btnr=12_0438&hg=12&fg=22

the regulator is num.10. you just have to uninstall num.22 (CONNECTION FLANGE) very easy to do. I had a similar case a couple of months back.

[shogun]

her how to change the voltage regulator
http://bmwe32.masscom.net/sean750/VoltageRegulator/VoltageRegulator.htm
Pong, you first have to check which alternator you have, there are different makers, for example Bosch or Valeo.

@Ferret
here you can buy the wire now, he even send me an email to thank me for the instructions how to do
http://cgi.ebay.com/ebaymotors/BMW-E31-E32-750i-850i-850ci-alternator-output-wire_W0QQcmdZViewItemQQhashZitem2557296287QQitemZ1 60376119943QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAcc essories

but easy to DIY, I used welding machinery wire.

[Tiger]

I would suspect the fusible links and the alternator.

[pong]

ill check the battery cable first tom, the negative cable i changed already since it was very corroded. most probably, the positive cable is likewise corroded
8 gauge wire or 6 gauge wire?

if that does not work, then ill go to the alt and the voltage regulator.

easier solutions first. hehehe

[tim eh?]

There should be 3 cables attached to the positive terminal.
The skinny one with the fusible link powers the 'E-box', the other skinny one splits and goes through the firewall to the front and rear power distribution boxes. The thick cable runs around the front of the firewall and then into a plastic box that runs along side the lhs of the motor. Inside there is a junction where it splits with one cable going to the starter and a thinner one to the alternator. Here is a pic with the box open after I cut the starter cable.

http://www.bimmernut.com/forum/attachment.php?attachmentid=6813&d=1243050037

I ended up running a new separate cable for the starter. Instead of replacing the alternator wire I hooked up a temporary replacement with new wire but there was zero change and the wire looks new and i get zero resistance so I just use the old wire still.

Since you want to get the easy things out of the way - maybe first you would like to check the other ground cable (engine to ground), especially since your battery ground was messed up... that takes around 2 minutes to replace. The front fusible link (and short cable to bat+) is also an easy one.

oem sizes are metric -16mm and 10mm - I used 4 and 8 gauge... you have to get heavy duty wire for the alternator cable.

[632 Regal]

voltage regulator main source, alternators almost never wear out. cant type much i have visitors... viruses.. ****in nicm using a type fix to make legible lol... this sux