1997 BMW 528 Rough IDLE

Tiny
DRE27
  • MEMBER
  • 1997 BMW 528
  • 6 CYL
  • 2WD
  • AUTOMATIC
My car is a BMW 528 i1997 E39 a couple of years ago I hit a median ever since then its had a rough idle I gave to it to a mechanic that doesnt know crap. He changed my fuel pump same problem. Im in mechanic class now so ive been fixing it myself. SO when I started working on the car it was a no start due to the last mechanic breaking to fuel line to the fuel pump anyways I changed the fuel pump and the assembly on both sides of the gas tank I have changed the coils, spark plugs, crankshaft sensor, camshaft sensor, changed the oil, pumped out the old gas and put in new gas so it starts now but same rough Idle any ideas what it could be for such a rough idle im guessing it could be air intake manifold gasket. Also I dont know what this is yet but on the codes that are popping up it says my fuel trim is damaged what is a fuel trim mean for this car?
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Saturday, December 27th, 2014 AT 1:32 PM

14 Replies

Tiny
JACOBANDNICKOLAS
  • EXPERT
The fuel trim is the amount of time the computer allows the injectors to stay open. This is how it adjusts the fuel mixture (rich / lean).

As far as the rough idle, it is most likely the result of a lean or rich mixture. Can you provide the code so I can look further into it?

And yes, a vacuum leak can also cause a rough idle.
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Saturday, December 27th, 2014 AT 7:06 PM
Tiny
DRE27
  • MEMBER
Thank you for replying so quickly right not my car is in my class we are on winter break now. I wont be able to get to back to my car until JAN 6. As soon I get it I will send you the code #.
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Sunday, December 28th, 2014 AT 7:29 AM
Tiny
JACOBANDNICKOLAS
  • EXPERT
Sounds good. Let me know.
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Sunday, December 28th, 2014 AT 8:07 PM
Tiny
DRE27
  • MEMBER
Ok I got my running. Its runs a lot better then it use to but still having idle problems when I turn it on when I rev it pass 2000 rpms it stabilizes it self.
When I drove the car it was driving great except for the brakes it felt when the idle goes down the brakes do not work takes along time for it to stop with my foot on the floor. What could this be a vaccum in the lines? I haven't checked the fluid level of the brakes yet that's something I will be working on tonight checking if the master cylinder still good.

The codes that my car is giving off is

P0173 : Fuel trim (bank 2)
P1189 : Fuel Control (bank 2 sensor 1)
P1188 : Fuel Control (Bank 1 Sensor)
P0170 : Fuel Trim (bank 1)
P0340 : Camshaft Position Sensor

I have changed the gas the spark plugs the coils the crank shaft and cam sensor fuel filter, fuel pump, sending sensor relays.

I Also am suspecting a gas leak when I drove the car there was puddle of gas underneath the car but when I put it in the garage to check I revved the car drove it around a lil more let it sit and idle nothing was coming out I checked under the car nothing was wet im thinking that a low pressure return fuel may be the culprit and also the for the rough starting idle.
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Wednesday, January 14th, 2015 AT 9:36 AM
Tiny
JACOBANDNICKOLAS
  • EXPERT
The fuel trims tell me the power control module (PCM) is trying to compensate for too little or too much fuel. The first thing you need to do is get the fuel leak repaired. Once that is done, clear the codes and see if they all come back. I feel at least one or two will go away.
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Wednesday, January 14th, 2015 AT 11:02 AM
Tiny
DRE27
  • MEMBER
Thank you
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Wednesday, January 14th, 2015 AT 11:30 AM
Tiny
JACOBANDNICKOLAS
  • EXPERT
I hope I was helpful. Let me know what you find.
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Wednesday, January 14th, 2015 AT 6:14 PM
Tiny
DRE27
  • MEMBER
This may seem like a stupid question but ive decided that while im putting the new manifold gasket im going to change the injectors ive reading up on them seems like the seals get brittle and can cause vacum as well besides they havent been changed as fas as I know 160,000 miles

im reading up on this but it seems the remanufactured injectors are much cheaper would you reccommend remanufactured injectors or is it just better to get brand new ones I just dont want problems later with the engine just wanted to know if you think remanufactured is reliable?
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Friday, January 16th, 2015 AT 10:02 AM
Tiny
JACOBANDNICKOLAS
  • EXPERT
Honestly, I have never had any trouble with remanufactured injectors. I would save the money.
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Friday, January 16th, 2015 AT 10:23 AM
Tiny
JACOBANDNICKOLAS
  • EXPERT
You do know you can get new o-rings, correct?
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Friday, January 16th, 2015 AT 10:23 AM
Tiny
DRE27
  • MEMBER
Yes I already got the new o rings just kinda figured they are old injectors maybe a good idea to change them while I have access to them now so I dont have to work twice later on
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Friday, January 16th, 2015 AT 10:30 AM
Tiny
JACOBANDNICKOLAS
  • EXPERT
I understand and that does make sense.
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Monday, January 19th, 2015 AT 6:03 AM
Tiny
DRE27
  • MEMBER
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Friday, April 24th, 2015 AT 9:11 AM
Tiny
DRE27
  • MEMBER
I have changed the hoses that go from the vanos to the crank case ventalation and the hose the goes from the bottom of the crank case to the oil dipstick it fixed the rough idle considerbly but it still has a vacuum when it starts still starting rough until it get enough vacuum and runs ok still loses vacuum at times while braking at times I suspect it to be another leak I have not been able to detect with carb cleaner. Was wondering if you had any ideas of where else these type of cars have common leaks

codes that popped up on the car yesterday

Po 111 IAT Sensor CKT range/performane

Pending: Po 340 crankshaft postion sensor A bank 1 circuit malfunction

Pending: Po173 fuel trim malfunction (bank 2)

Pending: P1189 bmw code dont know what that is

Pending: P1188 bmw code

P170 fuel bank trim malfunction bank 1

im also wondering why the blower on the car never stops now after turning off the car the only way to stop it is to disconnect the battery everytime the car is parked. Im thinking I may need a new ac control unit because the air when on is stuck on one setting which is the highest no matter if u have the lowest setting it just blows hard all the time blows cold only when it wants to.
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Friday, April 24th, 2015 AT 9:26 AM

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