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E34 (1989 - 1995)

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  #1  
Old 02-12-2013, 08:16 PM
Larrick Larrick is offline
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Mein Auto: 1994 525it
I guess the car just wanted a ride!

Drove with my son in his 525it up into the hills for a walk with the dogs.
The car ran smooth and strong up the steep hills.
When we tried to leave, the engine would turn over strongly but not want to start.
It was pitch dark out with very little moon light.
After a few attempts and a thorough once over with a flash light, I could detect nothing obvious.
It was dark and getting a little chilly and I had just increased my AAA towing distance to 100 miles.
We called for a tow truck and put the car in the driveway for the night.
I wanted to get a good listen to the starting attempt so I could ask a proper question on this forum tonight.
I put the hood up and asked my son to turn the key.
It started immediately and sounds great!
I will check everything out in the morning but have no idea what to look for.
I should be happy but am confused and also worry about whatever happened occurring again.
I asked if the car had been run low on gas recently. It hadn't.
If you remember my last thread about the engine running rough and it being a loose spark plug. There was some oil (very little) in two of the plug wells.
I know I have to change out the valve cover gasket.
But the car would have run poorly on the way up the hill before it decided not to start.
I will take a look at the plug wells in the morning. That is all I can think if doing until the problem happens again.
Any thoughts?
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  #2  
Old 02-12-2013, 08:20 PM
skuzlm3 skuzlm3 is offline
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It was either fuel or spark, cause crank was there.
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  #3  
Old 02-12-2013, 08:20 PM
skuzlm3 skuzlm3 is offline
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Sounds like you might have been low on gas and parked on a hill
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  #4  
Old 02-12-2013, 08:27 PM
Larrick Larrick is offline
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The car was parked on a fairly level spot and there was just over 1/2 a tank of gas. I do realize that it would be either fuel or spark but am always worried that a sensor can go bad. Is there a particular sensor which would cause the problem of no start if there is fuel and spark?
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  #5  
Old 02-12-2013, 08:31 PM
skuzlm3 skuzlm3 is offline
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Couple sensors or modules could have caused it, better get it diagnosed by someone with a good scanner before it leaves you stranded again.
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  #6  
Old 02-12-2013, 08:38 PM
Larrick Larrick is offline
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I will do the stomp test tomorrow as well.
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  #7  
Old 02-13-2013, 12:09 AM
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BMWFatherFigure BMWFatherFigure is offline
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Fuel filter never hurts, and check for debris in the tank. Even if was new recently, you could have got some dirt.
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  #8  
Old 02-13-2013, 08:41 AM
Larrick Larrick is offline
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The last time we had to tow the car, the problem was the fuel pump. I did not change the fuel filter at that time. I will do that today.
I upped my AAA tow milage to 100 miles after that. It is well worth it for the extra $40 per year.
So the only things which changed between it not starting and starting were: Moving the shifter from park to neutral and back a few times to load and unload car and the car being shaken around a bit during transport.
Is there any one particular sensor which would cause an engine to turn over and not start?
Is it simply a matter of fuel or spark?
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  #9  
Old 02-13-2013, 08:51 AM
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Monsignor Monsignor is offline
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That is the exact scenario of a CrankPS not working. Strong clean start but no fire.
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  #10  
Old 02-13-2013, 09:03 AM
Larrick Larrick is offline
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What does the fact that the engine did start tell me? Do the Crank position sensors fail completely of slowly? Are they hard to get at?
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  #11  
Old 02-13-2013, 10:27 AM
Larrick Larrick is offline
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I have been researching the replacement of a Crankshaft position sensor. Do you really have to remove the oil filter housing, upper coolant hose and engine lift points to replace the sensor?
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  #12  
Old 02-13-2013, 05:40 PM
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Monsignor Monsignor is offline
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Ive never had one fail (preventative maintenance) so I can't answer that first question but you absolutely don't have to remove all of that.
Your upper rad hose would be a great help. But I did it with it on. Get small hands to follow the wire under the intake manifold and unclip it. Its a Torx head I think 27 or 30. Twist it gently back and forth while pulling it out.

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1995 525iA 250k mi
2006 325i/6 57k mi
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  #13  
Old 02-13-2013, 06:31 PM
Larrick Larrick is offline
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Today the car started up right away. It runs great. Very smooth and powerful. Drove to the parts store and put in a bottle of fuel injection cleaner and filled up on 91 octane.
Pulled the coils and checked for oil. there was a tiny amount in two plug wells. (near the oil cap) Not enough to cause any trouble.
My son said he had spilled a little oil when he was putting some in last week. I have instructed him to use a funnel or we will never know how oil is getting into the wells.
I was told that the fuel filter on these cars is huge and would be difficult to clog.
A mechanic said that I would feel a miss or hesitation in the engine from time to time if the Crankshaft position sensor was failing. That has not happened.
The car was difficult to star after it was turned off at the store. It did start after a few attempts.
Drove the car for about 7 miles and turned it off. After about one hour it was again difficult to start. This time it took about six attempts.
Drove back the 7 miles and waited in the car with it running for about 15 minutes as my son went into a grocery store. The engine ran smooth at idle. I increased the rpm a few times to 3500 and held it and then let it back down.
The engine really purrs like the proverbial kitten.
When it would not start the last time, I banged on the gas tank under the fuel pump just because I have heard that helps a failing fuel pump sometimes. It started after that. Coincidence perhaps. We did put a new fuel pump in last year.
I was unable to perform the stomp test. I have done it successfully before but could not get it to work this time.
Should I give the fuel injection cleaner time to work?
Monsignor gives me hope in being able to locate, remove and check ohms on the crank P sensor.
A mechanic also told me that a code can be thrown but be incorrect because the problem may be in another component in the "stream" (as he put it) of the electrical flow of other related components.
If I try to start the engine and it will not start and I spray fuel into the carburetor....will that prove a fuel delivery problem?
Why would a faulty Crank sensor not allow for a start but allow for a perfectly running engine after it is started?
Any ideas a would be appreciated. I know this a hard one to diagnose over the forum. Thank you for trying.
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  #14  
Old 02-14-2013, 04:05 AM
Mamij Mamij is offline
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Quote:
Originally Posted by Larrick View Post
Today the car started up right away. It runs great. Very smooth and powerful. Drove to the parts store and put in a bottle of fuel injection cleaner and filled up on 91 octane.
Pulled the coils and checked for oil. there was a tiny amount in two plug wells. (near the oil cap) Not enough to cause any trouble.
My son said he had spilled a little oil when he was putting some in last week. I have instructed him to use a funnel or we will never know how oil is getting into the wells.
I was told that the fuel filter on these cars is huge and would be difficult to clog.
A mechanic said that I would feel a miss or hesitation in the engine from time to time if the Crankshaft position sensor was failing. That has not happened.
The car was difficult to star after it was turned off at the store. It did start after a few attempts.
Drove the car for about 7 miles and turned it off. After about one hour it was again difficult to start. This time it took about six attempts.
Drove back the 7 miles and waited in the car with it running for about 15 minutes as my son went into a grocery store. The engine ran smooth at idle. I increased the rpm a few times to 3500 and held it and then let it back down.
The engine really purrs like the proverbial kitten.
When it would not start the last time, I banged on the gas tank under the fuel pump just because I have heard that helps a failing fuel pump sometimes. It started after that. Coincidence perhaps. We did put a new fuel pump in last year.
I was unable to perform the stomp test. I have done it successfully before but could not get it to work this time.
Should I give the fuel injection cleaner time to work?
Monsignor gives me hope in being able to locate, remove and check ohms on the crank P sensor.
A mechanic also told me that a code can be thrown but be incorrect because the problem may be in another component in the "stream" (as he put it) of the electrical flow of other related components.
If I try to start the engine and it will not start and I spray fuel into the carburetor....will that prove a fuel delivery problem?
Why would a faulty Crank sensor not allow for a start but allow for a perfectly running engine after it is started?
Any ideas a would be appreciated. I know this a hard one to diagnose over the forum. Thank you for trying.

No, that's not how the cps fails. There are no misfires, at least for BMWs. It usually just dies, or gives you trouble starting up when cold, and will soon die entirely.

You should be replacing the cps anyway.

You can try this test that bimmer hero did. He poured boiling hot water onto his cps to heat it up, when it was cold. Sometimes the cps's cold resistance falls out of specs, but its hot resistance is still ok. Especially if that gets you started immediately when it previously did not, change it.

Anyway, I would change it. And only purchase OEM. Have you bought a new fuel pump relay ? That's another thing that will go. Please change that too to oem parts. And a new water pump and thermostat and your auxiliary fan and sensor confirmed working at both low and high speeds at hot and hotter temperatures. Then you won't have any typical overheating problems too.

Most other E34 issues are not showstoppers like these and they are quite uncommon anyway. For good measure, change your blue engine coolant sensor. Seems to cause overfuelling problems in winter for some people. Its cheap anyway even for OEM.
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  #15  
Old 02-14-2013, 08:56 AM
Larrick Larrick is offline
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I am in California so we do really have "cold" unless you live in the mountains.
I would change the cps today because they are so inexpensive but I keep reading that the change out procedure is complicated.
Fan removal, rad hoses,some even say intake manifold and oil filter housing!
I would just love to eliminate the cps as a problem so I can continue to troubleshoot.
If the engine runs perfectly, once started,can it be a bad cps?
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  #16  
Old 02-14-2013, 10:52 AM
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Monsignor Monsignor is offline
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Quote:
Originally Posted by Larrick View Post
I am in California so we do really have "cold" unless you live in the mountains.
I would change the cps today because they are so inexpensive but I keep reading that the change out procedure is complicated.
Fan removal, rad hoses,some even say intake manifold and oil filter housing!
I would just love to eliminate the cps as a problem so I can continue to troubleshoot.
If the engine runs perfectly, once started,can it be a bad cps?
Quote:
Originally Posted by Monsignor View Post
Ive never had one fail (preventative maintenance) so I can't answer that first question but you absolutely don't have to remove all of that.
Your upper rad hose would be a great help. But I did it with it on. Get small hands to follow the wire under the intake manifold and unclip it. Its a Torx head I think 27 or 30. Twist it gently back and forth while pulling it out.

Sent from Joe's Galaxy SIII via BimmerApp

You dont need to remove all of that like i said up top. Also, the crankshaft position sensor, not the cam position sensor, is not inexpensive. i paid like $100 for a bosche unit.

unless thats inexpensive to you? lol
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  #17  
Old 02-14-2013, 05:17 PM
Larrick Larrick is offline
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I changed the fuel filter today in my limited time. There was a lot of black gas and bits of debris. It started a bit better. There is injection cleaner and 91 octane being run right now.
I will give it a day or two and see if things clear out. Stomp test showed no faults 1444.
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