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E34 (1989 - 1995)

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  #1  
Old 05-08-2012, 05:39 PM
flip_232 flip_232 is offline
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Question Engine cut out when warm on acceleration?

Hey I have been using this site for info for years, but now I need help. I have a 1992 525i inline six cylinder, the issue is the engine cuts out and back in while accelerating and dies sometimes the check engine light comes on because the motor is cutting out but doesnt leave any codes. This only happens after it gets to normal temp and gets worse till you almost cant drive anymore. I had it in a repudible shop( didnt charge me a cent) for three weeks chasing dead ends all the normal stuff checks out. I cleaned the ignition control valve to no joy. the fuel pump checks out good too, I would love any input or advise on where and what to check next, directions would be good too as I am mechanically inclinded but not a heavy bmw guy. (I am not a profesional speller either )

Last edited by flip_232; 05-08-2012 at 07:20 PM. Reason: spelling
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  #2  
Old 05-08-2012, 06:06 PM
nwilson44 nwilson44 is offline
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Are you using premium fuel? Dumb question but it makes a difference
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  #3  
Old 05-08-2012, 06:38 PM
flip_232 flip_232 is offline
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Yes, i am running premium fuel and I seafoamed it to clean out bulid up.
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  #4  
Old 05-08-2012, 07:22 PM
flip_232 flip_232 is offline
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I do see there are alot of similar issues on here but I would like a logical list of checks or fixes to start with. Thank you all again... in advance.
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  #5  
Old 05-08-2012, 07:22 PM
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BMR_LVR BMR_LVR is offline
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Check the crankshaft position sensor. The instructions are clearly spelled out in the Bentley manual .... however ..... the resistance reading posted in the manual is incorrect. The manual lists 1280 +/- 10%. It should be 540 +/- 10%. Usually, the car will just stop running when the CPS goes out, however, sometimes they do create problems like yours.

However, the camshaft position sensor should be 1280 +/- 10%. It too can cause engine running problems like yours. They are not as common of a fail item though, but still, worth checking.
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1991 735i - Sold
1992 525i - Sold
1995 325is - Sold
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  #6  
Old 05-09-2012, 12:16 AM
robertobaggio20 robertobaggio20 is offline
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Clean out your throttle position sensor. It is located right next to your throttle body. Contact cleaner and soft rubbing would suffice, on both the tps and its connector. Then take your car for another test drive.

Please change out your crankshaft position sensor if you haven't already done so in the past 5 years. The sensor will fail on your car leading to no start situations. While I have not heard of buggy crank sensors causing problems as you've described, the sensor's resistance changes as the temperature increases, and if its slightly weak, the resistance may indeed increase to above a usable range once the engine (and the sensor) is hot. Furthermore, check the sensor's wires...there might be a break somewhere and it may be shorting to ground etc when the car is in motion.

Start your engine and bring it up to operating temp. Then, leaving it at neutral, rev your engine and see if it cuts out like it does when you are driving. If it doesn't, its likely some worn wiring/insulation that gets juddered about when the car is in motion.
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  #7  
Old 05-09-2012, 08:50 AM
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1995i540 1995i540 is offline
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Quote:
Originally Posted by robertobaggio20 View Post
Clean out your throttle position sensor. It is located right next to your throttle body. Contact cleaner and soft rubbing would suffice, on both the tps and its connector. Then take your car for another test drive.

Please change out your crankshaft position sensor if you haven't already done so in the past 5 years. The sensor will fail on your car leading to no start situations. While I have not heard of buggy crank sensors causing problems as you've described, the sensor's resistance changes as the temperature increases, and if its slightly weak, the resistance may indeed increase to above a usable range once the engine (and the sensor) is hot. Furthermore, check the sensor's wires...there might be a break somewhere and it may be shorting to ground etc when the car is in motion.

Start your engine and bring it up to operating temp. Then, leaving it at neutral, rev your engine and see if it cuts out like it does when you are driving. If it doesn't, its likely some worn wiring/insulation that gets juddered about when the car is in motion.
This has absolutely nothing to do with TPS and don't touch your CPS; if CPS fails your car would never start if you are using OEM part.
  1. Fuel delivery problems due to bad fuel pump/filter/injectors
  2. MAF or POST MAF air leak

Focus on those.
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  #8  
Old 05-09-2012, 08:55 AM
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Monsignor Monsignor is offline
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Quote:
Originally Posted by 1995i540 View Post
This has absolutely nothing to do with TPS and don't touch your CPS; if CPS fails your car would never start if you are using OEM part.
  1. Fuel delivery problems due to bad fuel pump/filter/injectors
  2. MAF or POST MAF air leak

Focus on those.
i agree with poor fuel delivery.
Pull injectors, have them cleaned if (probably dirty).
Replace fuel filter

Check spark plugs for wear, running rich/lean whatever. they could provide the answer.

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  #9  
Old 05-09-2012, 01:49 PM
flip_232 flip_232 is offline
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I have cleaned the MAF and I cant find any air leaks, The engine is just shutting off for a second then comes back on and the check engine light fashes as it shuts off and on rapidly if you let off the throttle it comes back on and if you apply the throttle lightly you can continue going, but sometimes it just flips on and off till you have to stop and then it dies, but it will start right back up like nothing is wrong. It is not storing a code so this is very hard to diagnose. I will check the injectors and check the pump again. Thank you all for being helpfull This car is getting more love(in the last few weeks) than it has gotten in a long time...lol
oh I will check the plugs too.
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  #10  
Old 05-09-2012, 02:42 PM
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1995i540 1995i540 is offline
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Check your fuel delivery.
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  #11  
Old 05-09-2012, 02:53 PM
flip_232 flip_232 is offline
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What do you mean by fuel delivery? does this mean fuel lines or something else Im not sure it is a fuel problem how does the engine being warm affect a pump in the rear of the car? If the injectors where dirty wouldnt the problem happen all the time and not just when it was warm I need some more info please.
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  #12  
Old 05-09-2012, 03:21 PM
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BMR_LVR BMR_LVR is offline
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As 1995i540 suggested, check your fuel pressure when warm.

Hmm ... problems with driveability when warm. One possibility is a bad O2 sensor.

This is a remote possibility, but the DME may be failing. It sounds as if the engine just loses signal to run.

Don't suppose you know of anyone who has a DME you could borrow do you? If so, you could swap it out to see if that is the problem. I certainly would not advocate buying another one without finding some way to define that as the problem for sure. Fortunately, they are relatively inexpensive used ($50 and up depending on where you find one).

Good luck and keep us posted.
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Most problems are usually something simple !

Quote:
Originally Posted by noego View Post
It's Deja Poo - as in, I've heard this **** before.
Steve

Calypso Red 1992 525i with 200K miles

1991 735i - Sold
1992 525i - Sold
1995 325is - Sold
2000 528i - Sold

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  #13  
Old 05-09-2012, 06:55 PM
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1995i540 1995i540 is offline
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Fuel pressure and PSI retention along with flow check.
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  #14  
Old 05-09-2012, 10:19 PM
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luckydog luckydog is offline
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I'm leaning toward fuel pump.But it could also be the White main engine relay wearing out,or the Blue fuel pump relay acting up .loose battery connections, low battery voltage, loose power or ground connections in engine bay. you will have to test and swap out many things to test and identify the culprit. I would preform the stomp test for possiable injector codes. And how old are your coils?.
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Last edited by luckydog; 05-09-2012 at 10:22 PM.
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  #15  
Old 05-10-2012, 10:10 AM
flip_232 flip_232 is offline
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I have done the stomp test many times and it doesnt show any codes, I am not sure of the coils age but the shop I had it in said they checked out good. Does the Fuel pump fail this way where it will randomly cut out as described above only when the engine is warm? I have no issues when the car is cold.
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  #16  
Old 05-17-2012, 09:41 PM
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luckydog luckydog is offline
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try changing the fuel filter ,that solved my hesitation issues on acceleration.
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  #17  
Old 05-17-2012, 09:52 PM
paperplane94 paperplane94 is offline
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Quote:
Originally Posted by luckydog View Post
try changing the fuel filter ,that solved my hesitation issues on acceleration.
^+1
This is the simplest thing to start with. Do it.

Besides, you probably aren't going to check your fuel pressure with an actual gauge anyway.

The fact that it runs poorly at a higher temp may just mean nothing except the fuel filter.

The fact is, the fuel filter is a good place to start. You don't know when it was replaced(you are supposed to replace it, part of maint. interval), so how do you know its not starving your engine of fuel at higher temps while accelerating when the ecu calls for more fuel?

JUST CHANGE IT!

1.relive fuel pressure by going to the fusebox and pulling the fuel pump fuse while the engine is running.
2.let it die, takes several seconds.
3. get your hose clamp socket and remove the probably factory hose clamps from the fuel filter.
4.remove lines and clean up spilled fuel, replace filter noting the direction of original filter. Dontforgretdontforgetdontforget.
5.reverse it up

a nice write-up:
http://www.bmwe34.net/E34main/Mainte...ce/Filters.htm

Last edited by paperplane94; 05-17-2012 at 09:54 PM.
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