I have an unusual issue! Please help me diagnose it

[Gobraves]

Vehicle:
2002 BMW 530i Manual, sports package with 142k

The problems:
My vehicle will start fine when its cold. I drive it to work/school for 18 miles or so and shut the engine off. If I decided to turn the vehicle on right after I shut the engine off, it will not turn on. All the lights will come on, but the engine will not turnover. The battery is new, so its not a battery issue. But after leaving the vehicle off for 20 minutes or so and the engine cools down, it will start just fine! It just will not start right back up after driving it on normal engine temperature.

The second problem:
When I accelerate from a stop in 1st gear, right before I change the gear to 2nd I get a little vibration from the under the vehicle. It seems to come from the front of the vehicle. A shutter if you will! It only happens in 1st gear and while accellerating from a complete stop. Funny thing is I had an automatic E39 couple of years ago that did the same thing and everyone told me it was the transmissoin that was going bad. Now, I got a manual E39 and I have the same problem with this shutter! :mad

Thank you in advance for your help.

[koewnie]

You could try checkin the groundcable/points. When your engine heats up it could change. Do a 4point reading on the altenator.

[Gobraves]

You could try checkin the groundcable/points. When your engine heats up it could change. Do a 4point reading on the altenator.

You think the alternator could cause the starting issue? Thats interesting because when I purchased the vehicle, it came with a maintenance history and one of the things that jumped at me was alternator replacement two years in a row!

[topaz540i]

Yea could be a ground then and they misdiagnosed as the alt. a bad crank position sensor might cause the car not to start either.

[JimLev]

Check the battery cables, they need to be clean and tight. Maybe the battery posts are dirty and when they get hot from a bad connection the starter can't pull enough juice to make it turn. Do you even hear the starter clicking?
Feel the battery terminals, if the are warm/hot you have a bad connection. Check the other end of the ground cable where it hooks to the body too.
The crank sensor won't prevent the starter from operating.
The other things that could effect the starter is the key being read by the EWS, the clutch interlock switch, or the starter relay.

[Gobraves]

Check the battery cables, they need to be clean and tight. Maybe the battery posts are dirty and when they get hot from a bad connection the starter can't pull enough juice to make it turn. Do you even hear the starter clicking?
Feel the battery terminals, if the are warm/hot you have a bad connection. Check the other end of the ground cable where it hooks to the body too.
The crank sensor won't prevent the starter from operating.
The other things that could effect the starter is the key being read by the EWS, the clutch interlock switch, or the starter relay.

I dont hear anything clicking when I turn the key. all the lights come one, the key turns but nothing happens. its quite! no clicking, no engine trying to start as it does when you have a bad battery. Nothing happens. I wait for several minutes, try it again and it starts the first time!

It only happens if I try to restart the vehicle after just turning it off. for example: I drove for 15 minutes last night and went to a pizza shop. parked the car, turned it off and went inside. I was probably gone for 10-15 minutes. come back to the car and it wont start. wait 10 more minutes or so and it starts on the first try!

could it be Alternator? Starter?

[16valex]

That's one hell of an annoyance problem you have. Like everyone had said check all your connection all the way to the starter for loose and corrosion.

Replace starter relay
Check for voltage at starter solenoid.

[larrym3711]

Little technical here: when magnetics (like a relay) heats up the net field is weaker and the mechanics involved may no longer activate until it cools down. This may be happening in any path to the starter from the key.....that includes the startervrelay

[Silverlight]

What an interesting problem you got there. I'm not super experienced so I can't really give you any valuable input that hasn't already been said, but best of luck for figuring it out.

[Gobraves]

Little technical here: when magnetics (like a relay) heats up the net field is weaker and the mechanics involved may no longer activate until it cools down. This may be happening in any path to the starter from the key.....that includes the startervrelay

Good point there! So what else are you suggesting I should check. Starter relay, cable connections to the battery, the alternator cables? anything else that can cause this?

[jstern]

Like all those above have said inspect all your starter/battery connections for corrosion and tightness. A little heat can really change things when there is corrosion or a loose connection.

Your second problem sounds like a component of the drive shaft is beginning to fail-guibo (rubber flex joint immediately behind the transmission) or center support bearing. You will need to get under the car with, at least, a flashlight and a mirror and look for cracks in the guibo. The exhaust system heat shields are in the way of inspecting the center support bearing. I have never had to inspect this part before on an E39, so maybe someone else can chime in with that inspection procedure-perhaps unbolting the heat shield and sliding it out of the way enough for you to see the CSB.

[koewnie]

You think the alternator could cause the starting issue? Thats interesting because when I purchased the vehicle, it came with a maintenance history and one of the things that jumped at me was alternator replacement two years in a row!

Read carefully.

You can check the alternator to see if ground is correct.
Didnt say it was broken, than it shoulnt start at al (except with a boost from a other car)
If readings are below 14.4v it could be bad cables or connections

[collardgreens]

Check the battery cables closely as mentioned. My positive cable fused/melted to another cord it was strapped to. It would get super hot and the car would shut off by itself.

Peered over the many grounding points in the engine bay and every wire I could find before I decided to check the battery.

[Gobraves]

Read carefully.

You can check the alternator to see if ground is correct.
Didnt say it was broken, than it shoulnt start at al (except with a boost from a other car)
If readings are below 14.4v it could be bad cables or connections

Thanks for your response. Can you please explain the reading below 14.4v a little further. What excatly I am reading, the Alernator? How do I read it? Sorry, I'm new to DIYer.

I have checked my battery cables. They're on tight with no visible corrossion or breaks.

Thanks,

[jstern]

Thanks for your response. Can you please explain the reading below 14.4v a little further. What excatly I am reading, the Alernator? How do I read it? Sorry, I'm new to DIYer.

I have checked my battery cables. They're on tight with no visible corrossion or breaks.

Thanks,

When you checked the battery connections, did you remove the connectors to inspect for corrosion. You must remove them because the corrosion lives in the hidden part.

[larrym3711]

If you are new to doing DIY, it may be best to have some auto parts supplier, like AutoZone test your battery AND alternator. In summary, your battery (engine off) should read 12.6 volts (or thereabouts) and, when the engine is running at 1000 rom or more, the voltage (at the battery) should show well above 14 volts. If NOT, one or the other (both?) is bad. If this turns out "OK", you need to look for other causes. I am MOST CONCERNED that the PO replaced the alternator twice in one year
. That is VERY unusual and may indicate a prevailing and recurring problem....and may still be present. I would go over the compete car to validate good (!!) electrical connections, with emphasis on ground connections under the hood. If you see ANY corrosion please correct it immediately. Your alternator may be going open circuit momentarily, causing damage to internal circuits. Another possible cause of premature failure is liquids, such as antifreeze, water, or oil getting into the internals of the alternator.

larrym3711
2001 540iA Sport

[m5hoot]

After driving, can you pull up on ramps or fairly quickly get up on jack stands? Whatever you do, be safe. Have GF, wife, whatever try the car when it is likely to not start and check the voltage at the starter while turning key and hopefully starter stays dead. Note voltage when key is turned and starter does not respond. You can check it later the same way when starter is cool and see if voltage is different, but I suspect it will be same and starter is going/gone. What happens if it starts and you shut if off repeatedly and re-start? When it is cold, will it start over and over 5 or 6 times if necessary?

I'll sub so see if you can see what is happening at the starter only when trying to crank.

[Gobraves]

After driving, can you pull up on ramps or fairly quickly get up on jack stands? Whatever you do, be safe. Have GF, wife, whatever try the car when it is likely to not start and check the voltage at the starter while turning key and hopefully starter stays dead. Note voltage when key is turned and starter does not respond. You can check it later the same way when starter is cool and see if voltage is different, but I suspect it will be same and starter is going/gone. What happens if it starts and you shut if off repeatedly and re-start? When it is cold, will it start over and over 5 or 6 times if necessary?

I'll sub so see if you can see what is happening at the starter only when trying to crank.

What would make the starter not work only when the vehicle is at a normal operating temperature? I'm just wondering. The vehicle starts fine and quickly the first time everytime I try to start it when the engine is cool/cooler. The only time it does not start is when I go somewhere, turn the engine off and try to restart right away.

I have checked the battery cables by removing them completely and checking them for corrossion. The battery is new and the cables look good. I have a auto zone mechanic who changed my battery last time look at it over the wknd and see what he says.

[m5hoot]

Starter is no different than any other motor and field can go open-all kinds of things can cause voltage to starter weaken with heat. You got any better ideas? You asked for thoughts so I tried to come up with something "different". If voltage is there then there is no reason starter should turn NO? If voltage is not there, start working up from there. Sorry if you wanted something easier. As often is the case, I note you failed to answer the questions I posed. We ask these questions for a reason. What happens if you start/stop in many cycles?

[alpha06]

Check the ground. I had a similar problem and ended up replacing a battery, alternator and lots of cash for no reason from the stealer. The problem was the ground.

[m5hoot]

There are lots of grounds. If you don't have 13VDC at the starter when it won't crank, then don't you know exactly what is happening? If you have 13V at the starter, but the starter won't spin, then you can run a heavy wire from starter to a more convenient ground and you will know. Why do you want to be telling people to "check grounds". I agree, now exactly what ground would you like him to check? Exactly where is it located on his car? Are you speaking from first-hand knowledge or what your mechanic found. If first hand, where was the ground that was loose? Please be exact.

[Skwisgaar]

I have a auto zone mechanic who changed my battery last time look at it over the wknd and see what he says.

Those guys aren't mechanics.

Problem 1. I think you have a loose ground somewhere and have no idea which one it is. This is one reason I despise trying to diagnose electrical issues.

Problem 2. The first thing I would check is the motor mounts.

[koewnie]

There are lots of grounds. If you don't have 13VDC at the starter when it won't crank, then don't you know exactly what is happening? If you have 13V at the starter, but the starter won't spin, then you can run a heavy wire from starter to a more convenient ground and you will know. Why do you want to be telling people to "check grounds". I agree, now exactly what ground would you like him to check? Exactly where is it located on his car? Are you speaking from first-hand knowledge or what your mechanic found. If first hand, where was the ground that was loose? Please be exact.

I am a mechanic and i would say check them all, im also dutch so my english isnt that good, thats why i just tell him to check them. If i have to explain myself in english a lot of technical details would be without a name (i dont know translation)

[m5hoot]

Your English is fine. I agree in concept top check grounds, but you can bypass that when you have a known *no start* condition going right to the starter-start there- and then depending on what you find, go backwards. It bothers me when some mechanic tells a owner who may not even be there that his whole problem was a ground and the owner mimics what he heard with no personal knowledge where the ground was or even if that was the true problem. Use a Healthy 13VDC solid source to the starter as it seems to crap out at will practically and go from there rather than work a mile down-stream looking for a needle in a hay stack. You can determine if a loose ground is the culprit so easily why make it difficult. Go to the easiest thinks first.

I'm have offered my advice based upon electronic knowledge. The OP can do what he pleases and take his chances. I don't tnink he intends to want to learn the easy way anyway so I'm done. When I have to start defending my advice which I know is pertinent and most direct, I just see no point in going further. he should tear car completely apart
looking for a loose ground that resets every 20 minutes or so. Gheez, does a motor field act like that??? Like Mark Cuban on Shark Tank "I'm out".

[Gobraves]

Starter is no different than any other motor and field can go open-all kinds of things can cause voltage to starter weaken with heat. You got any better ideas? You asked for thoughts so I tried to come up with something "different". If voltage is there then there is no reason starter should turn NO? If voltage is not there, start working up from there. Sorry if you wanted something easier. As often is the case, I note you failed to answer the questions I posed. We ask these questions for a reason. What happens if you start/stop in many cycles?

Sorry man I wasnt getting smart with you. I was only asking so that I can get educated what exactly the starter does.

Well the problem does not only happen when the vehicle is hot. Yesterday, I started the vehicle for the first time and as usual it started fine on the first try. I then turned it right back off 5 seconds later. I then tried to turn it right back on, and it wouldn't start eventhough it was still cold. it did however start the second try just couple of seconds later. I checked all the grounds (That I could find) and could not find any corrosion of cuts to any of the cables.

Could this be related to the keys?

[RocketSurgeon]

This is weird, but I'm curious. What happens if you start the car, do what you have to do then shut it back off. Quickly disconnect the battery for a minute then reconnect it, will the car start? That would indicate an issue with one of the many computers.

[m5hoot]

This is weird, but I'm curious. What happens if you start the car, do what you have to do then shut it back off. Quickly disconnect the battery for a minute then reconnect it, will the car start? That would indicate an issue with one of the many computers.

Really good, outside the box thinking. You may be on to something. I am leaning toward a heat issue, but transistors get hot too. I think he should try it! That is what we need MORE of here. Outside the square.

To the OP...remember that when you start the car and turn it off and try it 5 seconds later, the car is cold, but the starter windings have just had about 100 amps (likely more) surge through them as well as other items like the starter solenoid contacts. Not the key, but there are a few items that flow enough juice to get warm even though you would not feel it to YOUR touch. Make sense? What happens if when your car won't turn over (and we agree your battery is ok) if you also jump start your car as well? Do it the right way. Have car off. If possible, either jump to your battery terminals or your hot and ground points under the hood second. Hook negative lead up second. You might be surprised, but it also can make the whole deal more confusing.

[Gobraves]

Just wanted to update on the issue. Problem has been fixed!! I just got a new clutch, flywheel and all the little things that one should change once in there, and guess what, the starting issue went away!! Mechanic said becuase my clutch was so bad that when i pressed it down to start the car it wasn't engaging... or something similar. Anyway there you have it. Worn clutch CAN cause starting issues!

[16valex]

Just wanted to update on the issue. Problem has been fixed!! I just got a new clutch, flywheel and all the little things that one should change once in there, and guess what, the starting issue went away!! Mechanic said becuase my clutch was so bad that when i pressed it down to start the car it wasn't engaging... or something similar. Anyway there you have it. Worn clutch CAN cause starting issues!

Partial but not whole the culprit of your starting issue. Had you known you could have the clutch pedal sensor re-adjusted, or even deleted the clutch pedal sensor all together.

[Gobraves]

Partial but not whole the culprit of your starting issue. Had you known you could have the clutch pedal sensor re-adjusted, or even deleted the clutch pedal sensor all together.

That makes so much sense. I did figure it had something to do with that sensor. Because when I had the issue, I would press the clutch up and down few times and press it all the way down to get the vehicle started. Thanks for clearing that up. do you think my problem will comeback unless I adjust the sensor or delete it?

Thanks,

[Der Krieger]

The answer turned up in the fifth message on the front page - and you just paid $XXX-$X,XXX to have a clutch switch adjusted correctly. That's what failing to do proper diagnostics will cost you.

[Gobraves]

The answer turned up in the fifth message on the front page - and you just paid $XXX-$X,XXX to have a clutch switch adjusted correctly. That's what failing to do proper diagnostics will cost you.

Incorrect! I did not pay anything to get the switch corrected/adjusted. you misunderstood my update. My clutch was slipping bad so I bought a Luk clutch and flywheel kit and had a BMW shop perform the labor. After the clutch and flywheel job the starting issue went away.

[16valex]

That makes so much sense. I did figure it had something to do with that sensor. Because when I had the issue, I would press the clutch up and down few times and press it all the way down to get the vehicle started. Thanks for clearing that up. do you think my problem will comeback unless I adjust the sensor or delete it?

Thanks,

You may have to take a look at it. Just remove the kick panel and you will see how the disengage sensor works when the clutch pedal travel down. If you need to know how to delete the clutch circuit just let me know, I have a picture of it some where.

[Gobraves]

You may have to take a look at it. Just remove the kick panel and you will see how the disengage sensor works when the clutch pedal travel down. If you need to know how to delete the clutch circuit just let me know, I have a picture of it some where.

Yes, I would like to know how to delete it. I have tried with no avail. I would appreciate any information you can provide. thanks,

[16valex]

How to delete clutch disengage sensor.

Here it is.

Find the little connector then jump Blue and Violet together and leave it unhook but tie wrap out of the way or use tape.