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Discussion Starter #1
Hello,

My A/C has been acting up lately, so today I decided to get a FSU from BMW and replace the old one. I was pretty sure it was the FSU, because the A/C kept turning on and off. Anyways, I took out the old FSU and put in the new one. I re-connected the plug, feeling very :thumbsup:, I go to turn on the car and it doesn't turn on. The lights flickered but it wouln't turn on. I tried to jump the car, but no luck. So, my :thumbsup: quickly went to a :crying:. I don't know what it can be, any suggestions???

Thanks in advance.
 

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meter the battery when trying to jump it... make sure you have the voltage you need... there could be a number of things wrong... try jumping straight from the battery and make sure the jumper cables your using have good continuity and no resistance... could just be that your battery just took a dump on you... it may be time for a new one...
 

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I assume you are talking about the final stage and I also assume the vehicle started and ran prior to replacement? If so 2 things these cars do not take a conventional jump well. The battery needs to charge for a bit first. Also I have seen several people burn out a final stage by bending the probes against each other. This will than short out the harness. Hope this helps.
 

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Discussion Starter #4
I assume you are talking about the final stage and I also assume the vehicle started and ran prior to replacement? If so 2 things these cars do not take a conventional jump well. The battery needs to charge for a bit first. Also I have seen several people burn out a final stage by bending the probes against each other. This will than short out the harness. Hope this helps.
Hi,

I am talking about the Final stage unit and the car ran fine prior to replacement. I really doubt I bent the probes. I guess I could connect the cables and waita little while, than try to turn the car on.
 

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Bending the probes wont cause the car not to start but will create issues lights flickering. Just let the battery charge for a while it will start. It needs the CCA's to start.
 

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Discussion Starter #6
Bending the probes wont cause the car not to start but will create issues lights flickering. Just let the battery charge for a while it will start. It needs the CCA's to start.
I just tried again and no luck. Only this time after I turned the car off there was noise coming from the FSU area:dunno:. Does it matter if I use a portable charger instead of a car? Also, when you say charge the battery, are you simply referring to connecting the cables to the battery and leaving it on there for awhile? Sorry for all the questions.

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I just tried again and no luck. Only this time after I turned the car off there was noise coming from the FSU area:dunno:. Does it matter if I use a portable charger instead of a car? Also, when you say charge the battery, are you simply referring to connecting the cables to the battery and leaving it on there for awhile? Sorry for all the questions.

Thanks

yes leave it sit for awhile... it would be ideal to use a car as they don't need to be recharged and provide constant current and voltage...
 

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No its better to use a charger but most portable chargers take a while. Sounds like the drain from the old bad final stage did a number on your battery.
 

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I was replying to his post not yours whoops should have quoted sorry. But if you want ill explain a charger will regulate the current and voltage and be steady a car jumping another car will not.
 

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Older BMWs, and I assume ours are the same, shut off all power after the battery gets below a certain voltage level. (to protect the delicate electronics) If this had happened to your battery, a jump start may not have helped, as your battery has to be above the cutoff level to power ancilary devices. Therefore, it is best to charge overnight (slow charge is least harmful), and then try to start. A jump start is OK (as stated in the Owner's Manual), but I would be very careful it has enough CCAs to get our cars started. They take a "ton" of juice to start.
 

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Older BMWs, and I assume ours are the same, shut off all power after the battery gets below a certain voltage level. (to protect the delicate electronics) If this had happened to your battery, a jump start may not have helped, as your battery has to be above the cutoff level to power ancilary devices. Therefore, it is best to charge overnight (slow charge is least harmful), and then try to start. A jump start is OK (as stated in the Owner's Manual), but I would be very careful it has enough CCAs to get our cars started. They take a "ton" of juice to start.
about 300 amps... meter the battery... thats how ull know when you have enough...
 

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1. You will never start our cars off a portable charger. You are wasting your time. For that matter, don't bother trying to jump it with your wife's Honda, either. You need a donor vehicle that also has a large battery and alternator - think full size pickup truck or SUV. If you'd like to trickle charge your battery overnight you'll be fine, but those carry along packs are useless.
2. You probably killed the battery by keeping the door open too long and, as JClyman, drained the battery.
3. Putting an ammeter on your battery tells you nothing you don't already know - that you aren't producing enough amperage to turn the starter. You can't say it takes 300A (or 200 or 400 or a million) unless you know the temperature of the engine, the condition of the engine (piston compression), the weight of oil in the engine, and about 20 other things.
4. Putting a voltmeter on you battery will give you useful knowledge after you get it charged. If you battery isn't at 12.6V or greater after a charge then it is time to start looking into a new battery. If it is about 12.4V or less you need to get a new battery now.
4. Whether you go straight to the battery or use the jumping terminals in the front isn't going to make much difference. The only difference is the length of wire you go through to get to the starter; Given that the engine ground is the equivalent of a 0 gauge wire and the positive wire is 0 gauge, and both of those are considerable larger than your jumper cables, just use the terminals under the hood.
5. I'm surprised it hasn't come up, but you can start the car by rolling it and releasing the clutch in 5th gear.

d-
 

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5. I'm surprised it hasn't come up, but you can start the car by rolling it and releasing the clutch in 5th gear.

d-
+1

Last time my battery died, I was in a parking lot at the airport. Had a airport 'motorist assist vehicle' try to jump it- no luck. They had big cables, beefed up alternator, integrated plug for the cables out on the front of the bumper....so...

I thanked them, and then proceeded to push the car from the high spot I was parked to the low spot where the drain was...about 300 feet away with a drop of 4-5 feet. Not much of a hill! After maximal exertion I was at a fast walk, around 4-6mph...jumped in and popped the gear in first...started.

It will ALWAYS be safer for the electronics to roll start than jump. IMHO

A
 

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As always, I agree with our board gurus, Doug & Adam (ard).

If it had been me, and I was on a slope, or could push it to a slope (man it's tough to push on level ground), I would have used Doug's # 5 point (and ard's example) to start. Don't know why I, too, didn't suggest that as I believe it is safer than jumpstarting. But, I guess I would have had to be there ... as they say. Assessing the situation with my own eyes.

Oh, yea, buy a trickle charger and use it. It's less costly than a tank of gas. And, more importantly, it works like a charm. My battery is 5.5 years old. I put my car on a trickle charger and it has be on one for up to 9 months. I just disconnect, jump in, and it starts right up!
 

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+1

Last time my battery died, I was in a parking lot at the airport. Had a airport 'motorist assist vehicle' try to jump it- no luck. They had big cables, beefed up alternator, integrated plug for the cables out on the front of the bumper....so...

I thanked them, and then proceeded to push the car from the high spot I was parked to the low spot where the drain was...about 300 feet away with a drop of 4-5 feet. Not much of a hill! After maximal exertion I was at a fast walk, around 4-6mph...jumped in and popped the gear in first...started.

It will ALWAYS be safer for the electronics to roll start than jump. IMHO

A
Its also a good idea (talking to people that have never clutch started before) to keep you feet over you brake for this process... and do not do it if your battery is completely dead, because your car will not start and you could snap a mount...
 

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+1

Last time my battery died, I was in a parking lot at the airport. Had a airport 'motorist assist vehicle' try to jump it- no luck. They had big cables, beefed up alternator, integrated plug for the cables out on the front of the bumper....so...

I thanked them, and then proceeded to push the car from the high spot I was parked to the low spot where the drain was...about 300 feet away with a drop of 4-5 feet. Not much of a hill! After maximal exertion I was at a fast walk, around 4-6mph...jumped in and popped the gear in first...started.

It will ALWAYS be safer for the electronics to roll start than jump. IMHO

A
I've had that exact same experience. I laughed at the airport guy when he pulled out the portable jumper and told him we needed to go vehicle to vehicle. He scoffed until he hooked it up and my car didn't even try to turn over, let alone get a revolution out.

Rolling works - and you can do it on flat ground with about 1 friend as well.

My only observation is that popping it in 1st gear is hard on the clutch and the driveline - 4th or 5th will start the car just as well but without the shock...

d-
 

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I've had that exact same experience. I laughed at the airport guy when he pulled out the portable jumper and told him we needed to go vehicle to vehicle. He scoffed until he hooked it up and my car didn't even try to turn over, let alone get a revolution out.

Rolling works - and you can do it on flat ground with about 1 friend as well.

My only observation is that popping it in 1st gear is hard on the clutch and the driveline - 4th or 5th will start the car just as well but without the shock...

d-
Reverse also works well. Although reverse has so much torque, its like a guaranteed start
 

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Its also a good idea (talking to people that have never clutch started before) to keep you feet over you brake for this process... and do not do it if your battery is completely dead, because your car will not start and you could snap a mount...
I'm not sure I understand that one -- you could have no battery and your car would continue to roll and run if you have the right leverage to get it started initially.

In 1st gear, the car will come to a dead stop (see my point above about shock on the driveline), but it will do this if you aren't going fast enough to turn over the motor too.

Taller gears give you better leverage on the motor - more turns of the wheel = less turns of the motor = greater torque applied through the clutch into the crankshaft.

Lastly, the battery is only there to power the starter - once you start the car the alternator provides all the energy the car needs to keep itself going. You could, although I wouldn't recommend doing so for practical reasons, remove the battery from the circuit altogether and your car would run just fine (once you got it started by rolling it down a hill!).

d-
 
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