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E34 (1989 - 1995)

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  #1  
Old 03-15-2014, 03:08 PM
brotherwise brotherwise is offline
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Location: California
 
Join Date: Mar 2014
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Mein Auto: 1995 BMW 540i
Sudden cut off and or rough idle/stall help pls.

I do not see a post that addresses the exact symptoms I see in my car so I am starting this thread. I am aware of possible issues, but I am posting in hopes of being a bit more exact because I have a very limited budget.

Symptoms:
*When cold, the car seems to run just fine.
*Once warm and the idle reduces near 1000 RPM, the idle may or may not suddenly drop and a check engine light accompanies it.
*The engine may or may not recover from the said drop and or even cut off.
*Some times the check engine light and drop in RPM occurs when accelerating.
*On restart, the engine always restarts but the event may or may not be immediate.

Attempts to correct:
*Fuel filter replaced, still not fixed.
*Air intake control valve cleaned with brake cleaner, no fix.
*Air filter change, no fix.
*MAF cleaned with MAF cleaner, no fix.
*Vacuum leak sought with carb cleaner, nothing detected.
*Spark plugs cleaned, no fix.
*Fuel injector cleaner added to fuel mix, no fix.
*Lubricated throttle body, no fix.
*Removed MAF connection, no fix, it will still idle for a while and then stall.
*Raised RPM to prevent shut off only displays erratic RMP.


Because the RMP drop isn't constant, the warm/cold engine may not matter.
When I slap the MAF the engine dies. Is the MAF designed to shut off when it's slapped or is this a sign of a bad MAF?
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  #2  
Old 03-15-2014, 03:58 PM
E34ZombieHunter's Avatar
E34ZombieHunter E34ZombieHunter is online now
Nothin like an E34
Location: Lillington NC
 
Join Date: Feb 2013
Posts: 1,605
Mein Auto: 95 540i B/B
Have you checked for codes? Do the stomp test to see what the codes would be, even with the light back off, if it is, you will have codes stored from when it was on.
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Gotta love an E34!!:thumb up:
If you want to get junkyard parts remember one thing, if it was wrecked you know it was running/driving. You may not know how well, but it was.
Quote:
Originally Posted by BMR_LVR View Post
So a synopsis of a normally operating fan clutch:

Engine stone cold - fan clutch engaged
Engine at normal operating temp - fan clutch disengaged (easily stopped with the newspaper)
Engine above normal operating temp - fan clutch engaged
STOMP TEST

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  #3  
Old 03-15-2014, 04:33 PM
brotherwise brotherwise is offline
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Location: California
 
Join Date: Mar 2014
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Mein Auto: 1995 BMW 540i
No I didn't check the code and I don't know what the stomp test is. I will perform the stomp and go from there. Thanx.

Last edited by brotherwise; 03-15-2014 at 04:39 PM.
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  #4  
Old 03-15-2014, 06:45 PM
E34ZombieHunter's Avatar
E34ZombieHunter E34ZombieHunter is online now
Nothin like an E34
Location: Lillington NC
 
Join Date: Feb 2013
Posts: 1,605
Mein Auto: 95 540i B/B
First post, if you need help, post a video of you doing the test and we can tell you what you are doing wrong or can decipher the codes for you.
http://www.bimmerfest.com/forums/sho...d.php?t=525152
__________________

Gotta love an E34!!:thumb up:
If you want to get junkyard parts remember one thing, if it was wrecked you know it was running/driving. You may not know how well, but it was.
Quote:
Originally Posted by BMR_LVR View Post
So a synopsis of a normally operating fan clutch:

Engine stone cold - fan clutch engaged
Engine at normal operating temp - fan clutch disengaged (easily stopped with the newspaper)
Engine above normal operating temp - fan clutch engaged
STOMP TEST

OEM Approved brands
READ ME IM THE BIBLE
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  #5  
Old 03-15-2014, 08:46 PM
jessyjaymes jessyjaymes is offline
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Location: Las Vegas
 
Join Date: Mar 2014
Posts: 27
Mein Auto: E36 1995 325iS coupe
Sounds silly but check your the rubber seal around your oil filler cap!


Sent from BimmerApp mobile app
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  #6  
Old 03-16-2014, 07:23 AM
Mr._Graybeard Mr._Graybeard is offline
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Location: Wisconsin
 
Join Date: Oct 2011
Posts: 155
Mein Auto: '95 540i, '87 325ic
Quote:
Originally Posted by jessyjaymes View Post
Sounds silly but check your the rubber seal around your oil filler cap!


Sent from BimmerApp mobile app
I like that, or a cracked air intake boot. Vacuum leak somewhere.
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  #7  
Old 03-16-2014, 07:38 AM
Mamij Mamij is offline
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Posts: 574
Mein Auto: BMW 320i M52 1996
Quote:
Originally Posted by E34ZombieHunter View Post
First post, if you need help, post a video of you doing the test and we can tell you what you are doing wrong or can decipher the codes for you.
http://www.bimmerfest.com/forums/sho...d.php?t=525152
Hi Zombie, I think it would be more useful for you to put the link to the stomp test in your siggy. The stomp test is the first place everyone should look towards if they are running american cars with a CEL.

OP (original poster), your sudden cut off could either be a busted or disconnected ICV (idle control valve), or a busted (not disconnected) tps (throttle position sensor).

Get the stomp test working first. If you can't, then disconnect your tps, it has been known to cause such issues although rare, and it is very dangerous for that reason. I always recommend that people change their tps to a new one, its only $45 oem and its a 5 minute DIY job.

Good luck.
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  #8  
Old 03-18-2014, 10:33 AM
brotherwise brotherwise is offline
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Location: California
 
Join Date: Mar 2014
Posts: 4
Mein Auto: 1995 BMW 540i
I performed the stomp test and found the code 1215 - Mass Air Sensor.
I guess the sensor should not cause the engine to stop when slapped. <---That was my big question.
Thank you again for your responses and letting me know there is a stomp test.
I will replace the MAF sensor and see if it solves the problem.
I will return here to continue problem solving if it doesn't work or to let you all know that it's solved.
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  #9  
Old 03-28-2014, 12:01 PM
brotherwise brotherwise is offline
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Location: California
 
Join Date: Mar 2014
Posts: 4
Mein Auto: 1995 BMW 540i
I went to a Pick A Part and searched for a Mass Air Sensor and found one.
(Funds are too low for a new part.)
I found it on a 7 series that actually looked strangely like my 540i.
(That particular assembly looked new as if it had been replaced)
I installed the sensor after comparing the two and they were exact match.

The idle is now smooth, the shifting is smooth and definitely no stalls.
Thank you all for your help.
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  #10  
Old 03-28-2014, 12:39 PM
E34ZombieHunter's Avatar
E34ZombieHunter E34ZombieHunter is online now
Nothin like an E34
Location: Lillington NC
 
Join Date: Feb 2013
Posts: 1,605
Mein Auto: 95 540i B/B
Quote:
Originally Posted by brotherwise View Post
I went to a Pick A Part and searched for a Mass Air Sensor and found one.
(Funds are too low for a new part.)
I found it on a 7 series that actually looked strangely like my 540i.
(That particular assembly looked new as if it had been replaced)
I installed the sensor after comparing the two and they were exact match.

The idle is now smooth, the shifting is smooth and definitely no stalls.
Thank you all for your help.
That was an E32, VERY similar to the 540i.
Most 540i engine related parts can come off of an E32, E34, and E38 as i have found when i cross check part numbers before going to the pick a part.
realoem.com
Plug in you vin(lasst 7)
Then go through and find the part you want the part number for
Copy the part number and go back to the page where you entered your vin and paste that number, it will then tell you what cars to look for that have the same part.
__________________

Gotta love an E34!!:thumb up:
If you want to get junkyard parts remember one thing, if it was wrecked you know it was running/driving. You may not know how well, but it was.
Quote:
Originally Posted by BMR_LVR View Post
So a synopsis of a normally operating fan clutch:

Engine stone cold - fan clutch engaged
Engine at normal operating temp - fan clutch disengaged (easily stopped with the newspaper)
Engine above normal operating temp - fan clutch engaged
STOMP TEST

OEM Approved brands
READ ME IM THE BIBLE
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  #11  
Old 03-28-2014, 01:40 PM
capricornbmw capricornbmw is offline
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Location: Many places
 
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Posts: 386
Mein Auto: E36
Great. Now goto another pickapart and get another maf as a backup. You should have a spare maf and a non-ews ECU at all times, and since they are likely to be good used parts, if you end up using the spare, well then you need to have yet another as a spare.

This is if you intend to hold the car for the forseeable future.

MAFs and dmes can be resold easily for the same or slightly higher price. Anything you lose along the way, is considered an insurance premium for peace of mind, and is well worth it.
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