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E34 (1989 - 1995)

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  #1  
Old 04-22-2013, 03:49 PM
535iofdoom 535iofdoom is offline
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Question Electrical Power Surges e34 535i

alright were to begin.

one fine winter day i was driving, suddenly the check engine light started flashing, the blower motor started running hard and the radio would cut out. all this happens randomly and in short 1-2 seconds bursts.. from what research i have done it may be 1]alternator 2]voltage regulator 3]battery, take in mind these are the common causes.

engine] 3.5(3.4 really but whos counting.) inline 6, +90,000 miles
alternator]115amp
battery]new, something or other. i didnt buy it.

there is a 2200 watt system in the car. 1200 to the subs, 1000 to the inside speakers. again not me.

off to the trouble shooting.

tested alternator, 14.7 volt. so "working" properly
tested battery, charged with no random draw
all connections look good and are tight.

not tested, havent checked the ground strap.. yet, still cold outside.

now the questions

could it still be the voltage regulator? $116.00 yes my alternator is serviceable.

where should i start looking to track this problem down?
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  #2  
Old 04-22-2013, 11:13 PM
535iofdoom 535iofdoom is offline
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Bump.

Please help?

Lol anything
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  #3  
Old 04-23-2013, 02:18 AM
allenbee allenbee is offline
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At 14.7 volts your alternator seems way too high. I'm thinking 14-14.2 max. (Correct me if I'm wrong here.) Voltage regulator likely. Voltage may be even higher during driving when you can't test it. This will overload your battery eventually.

115A alternator seems a tad conservative for a 2200watt system.

Alternators can only be properly checked out via a load testing machine.

What are the uncommon causes of your issue, based on the research that you have done ?

Do the stomp test to see if there are any relevant error codes. You'll find the stomp test methods on youtube.

Last edited by allenbee; 04-23-2013 at 02:33 AM.
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  #4  
Old 04-23-2013, 06:01 AM
92fatboy 92fatboy is offline
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I'm also curious for thoughts on this. I stated basically the same thing on a thread yesterday.
My check engine light flashes never staying on for more than a second and may continue like this for up to 10 miles on the intersate. While it's flashing the the odometer and drive indicator pulse along with my headlights if they're on. Stomp test won't work or I haven't got the hang of it (don't know) but it leaves me with a lack of confidence to start driving when I could end up on the side of the road.
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  #5  
Old 04-23-2013, 11:49 AM
MySatinDoll MySatinDoll is offline
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If there's not lighting cap (looks like a large AA battery connecting the positive and negative leads off the battery to the aftermarket amp and common ground)
That can be one source of your problems.
Do a stomp test:
(brief instructions due to time constraints )
1. turn key to start position (do not start car)
2. step on gas pedal 5 times.
3. check engine light should go out then begin to blink in a specific sequence.

That sequence is the codes. If your seeing 1231. That's your battery, altenator, or starter

This said I'd gather that your altenator isn't charging the battery
or you have a voltage drain somewhere in the specified system.
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  #6  
Old 04-23-2013, 07:03 PM
92fatboy 92fatboy is offline
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Sorry if I piggybacked on this thread. I got the stomp test to work. Finally.
Code is just as mentioned above 1231. Battery, Alternator or Starter. Where do I start?
Car starts and runs fine. again for the record. '92 525i with 306,000
Thanks in advance.
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  #7  
Old 04-23-2013, 07:14 PM
allenbee allenbee is offline
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Quote:
Originally Posted by 92fatboy View Post
Sorry if I piggybacked on this thread. I got the stomp test to work. Finally.
Code is just as mentioned above 1231. Battery, Alternator or Starter. Where do I start?
Car starts and runs fine. again for the record. '92 525i with 306,000
Thanks in advance.
Either load test your alternator, or have your battery's CCA tested with those handheld digital meters.

Another thing to do would be to hook up your car to another one with a known working battery and alternator, with jump start cables. Start both engines. See if the problem recurs. If it doesn't then you know its the battery or alternator.

If it doesn't, then shut off the other car but leave the cables connected. If the problem recurs then you know its your alternator but not your battery. If it stays away then you know its the battery but not the alternator.

Clear all error codes first before doing this. You don't want to read old codes.

If your problem is an intermittent one, then you've got no choice but to get your batt and alternator properly tested.
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  #8  
Old 04-24-2013, 05:49 PM
535iofdoom 535iofdoom is offline
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Exclamation sooo...

as far as uncommon causes.. nothing really outside the alt, vr or battery.

however today my tranny went into limp mode, unhooked the battery to reset ecm.

decided to stomp check for new codes and got 1231 (dme main relay).

im going to replace this tomorrow and see if any of above mentioned issue resolve.

will update.

ps. thanks for the help
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  #9  
Old 04-24-2013, 06:58 PM
92fatboy 92fatboy is offline
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Electrical Power Surges e34 535i

I thought 1231 was a battery,alternator, starter. Is the DME in the same loop.


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  #10  
Old 04-24-2013, 07:36 PM
535iofdoom 535iofdoom is offline
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Quote:
Originally Posted by 92fatboy View Post
I thought 1231 was a battery,alternator, starter. Is the DME in the same loop.


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Battery voltage / DME relay

So yeah maybe same loop
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  #11  
Old 04-24-2013, 08:18 PM
allenbee allenbee is offline
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Its always a good idea to get a new fuel pump relay and main relay, oem. And if you can afford it, a new cps and fuel pump and engine coolant sensor, also oem. The parts prices are low and they can be diyed or all done under 2 hours shop time. Staves off way too many problems to ignore. No starts, hard starts when warm or cold, trans prog errors, and now possibly this one in this thread. This is if you're buying the car off a non-enthusiast.
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  #12  
Old 04-27-2013, 07:22 AM
92fatboy 92fatboy is offline
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So the alternator is bad and I discovered that I have a Valeo and not a Bosch. 140v. Of course the Valeo is more expensive than a Bosch and the Autohauz website says Bosch will not replace a Valeo. Ive seen some old posts where users have modified the bosch to fit but does anyone know the difference or why it may have been OEM on a certain model year.
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  #13  
Old 04-27-2013, 08:46 AM
allenbee allenbee is offline
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Bosch will replace a valeo alternator, as long as its for the same engine. Dickhead website. I have done this before for 2 weeks while
rebuilding my alternator.

Last edited by allenbee; 04-27-2013 at 08:51 AM.
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  #14  
Old 04-27-2013, 09:59 AM
535iofdoom 535iofdoom is offline
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alright good news first.

replaced dme/fuel relay and main relay, still getting 1231 and power surges.

replaced the cap and rotor and no more power surges.

lol i didnt know they were both still factory, worst cap and rotor i have seen in a long time.

bad-ish news.

getting 1222 or lambda 1 code now. hard starts and rough idle.

I DO have a custom cold air intake on the car. i am thinking this may be screwing with the MAF, ideas?

doing vacuum hoses today to see if it helps ha. wondering if any of you have had exp with this code

again thanks for your guys help on the power surge issue

Last edited by 535iofdoom; 04-27-2013 at 10:06 AM.
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  #15  
Old 04-27-2013, 09:17 PM
allenbee allenbee is offline
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Quote:
Originally Posted by allenbee View Post
Bosch will replace a valeo alternator, as long as its for the same engine. Dickhead website. I have done this before for 2 weeks while
rebuilding my alternator.
What you may not find on Bosch is the same 140a alternator. You might find 90A or 120A. And the Bosch and Valeo units looks different. But everything else, mounting points, position of pulley, position of cooling duct, etc, is identical.
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  #16  
Old 04-27-2013, 09:44 PM
allenbee allenbee is offline
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Quote:
Originally Posted by 535iofdoom View Post
alright good news first.

replaced dme/fuel relay and main relay, still getting 1231 and power surges.

replaced the cap and rotor and no more power surges.

lol i didnt know they were both still factory, worst cap and rotor i have seen in a long time.

bad-ish news.

getting 1222 or lambda 1 code now. hard starts and rough idle.

I DO have a custom cold air intake on the car. i am thinking this may be screwing with the MAF, ideas?

doing vacuum hoses today to see if it helps ha. wondering if any of you have had exp with this code

again thanks for your guys help on the power surge issue
CAI will not create codes on the car.

Clear all the codes. Do the vacuum hoses. Make sure everything is tightened down when you are finished - including the brake booster hose. Then restart the car, check for codes.

The hoses will probably not fix anything. But it will help your car run perfectly when you do find the problem.

If you've done all of this and the problem is still there, you need to do the disconnect test.

Shut off the engine and disconnect the following drivability sensors one by one, reconnecting the last before going to the next :

1. MAF
2. ECTS, engine's coolant temp sensor, blue tip not brown, under the intake manifold on the cylinder head, and closest to the front of the engine.
3. O2 sensor (remove the relay to disconnect, its in the ecu bank area)
4. ATS (air temp sensor, somewhere under the brake booster fitting, under the intake manifold.)
5. ICV. Tight fit under the intake manifold (m50 engines), but you can just about get to it if you remove the alternator's cooling duct and snake your fingers through that way.

Then start the engine and watch it for a minute. Shut off and go onto the next.

Any one of those sensors, if screwed and not automatically deactivated by the car, can lead to rough running. The car doesn't always deactivate a bad sensor as its an early generation fault reporting system, not too precise. So it may still take readings from a bad sensor and use them.

Disconnecting a sensor causes the dme to deactivate it and use stored factory values in its place. This won't give you perfect power and fuel economy, but it will avoid problems like rough running. So, disconnect the screwed sensor, and the car suddenly behaves normally. That's how you know, or can confirm suspicions.

Don't disconnect more than 2 at one time. That can lead to rough running anyway in some cars. And when you disconnect a sensor that's in a tight spot, leave the connector close by so its easy to shove in again later.

May take you something like 10-45 minutes for all of this if you're familiar with accessing each sensor. If not may take you 45 minutes. Took me a time to figure out how to get to the ects and icv and now I've got the hang of it.

Delete all codes after you're done.

--

If you find a bad sensor, delete codes and restart the engine. Sometimes that fixes it. If it doesn't, get a new one and leave the old sensor disconnected meanwhile.

Only buy new oem for sensors, they are cheap. The more expensive sensors like O2 are worth paying for oem, as they last for years and years. The maf, you can safely buy a used good oem unit, don't buy new ebay units made in china. New oem mafs are very expensive, and not necessary.

===========
OP, if this doesn't isolate the problem, then pull your plugs and look at them. Clean them off with brakeleen and reinstall if they look fouled. If you have oil in your plugs' well, clean that off and replace the valve cover gasket later.

Last edited by allenbee; 04-28-2013 at 02:20 PM.
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  #17  
Old 04-27-2013, 09:47 PM
allenbee allenbee is offline
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If you find a bad sensor, delete codes and restart the engine. Sometimes that fixes it. If it doesn't, get a new one and leave the old sensor disconnected meanwhile.

Only buy new oem for sensors, they are cheap. The more expensive sensors like O2 are worth paying for oem, as they last for years and years. The maf, you can safely buy a used good oem unit, don't buy new ebay units made in china. New oem mafs are very expensive, and not necessary.

Last edited by allenbee; 04-27-2013 at 09:49 PM.
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