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e39 Rough idle - early morning start or when cold

98K views 152 replies 41 participants last post by  Patrickhouston 
#1 ·
So my 2003 530i has been very good so far with the exception of some rough idling in the morning. This started in the winter.

One day when I started it to let it warm up. When I got in the car, the engine light was on the gauges were all messed up, and it sounded like it was running on three cylinders. I turned off the car, restarted the it and it was running better, eventually the check engine light went off. This was the worst scenario.

The daily scenario now is that when I start the car, the idle is rough until it warms up. No check engine light. I've noticed this happens on the odd occassion when I drive the car during the day.

What have I done so far:
1) Took it to the shop - they checked the computer no codes. Mech suggested it might be a dripping injector, but he said wait until its real bad and bring it back.

2) Checked the forum, tried disconnecting the MAF before start, then started it, seem to run a little better, but I still noticed the miss. I read you can clean the MAF, how do you do that without messing it up?

Not sure what to try next.:dunno:

Any suggestions greatly appreciated...thanks.
 
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#61 ·
Hey, Igor, why do you want to change the SAP? I just changed the check valve & the salmon relay as a preventative measure as per the BMW bulletin - I had no issues, but when I pulled the check valve it was caked with carbon deposits and started to show some rust, so maybe you would need to change only these 2 items which are much cheaper than the SAP, which if it doesen't suck humidity (failed check valve), or if it's not stuck running continuosly (stuck relay) should last indefinetly (due to the fact that it runs only a few dozen seconds when the engine is cold started) :dunno:







 
#64 ·
Question about the coils...those look like the older style of coils. The bosch coils are around $43 CDN/each. But they also have some that are Direct Ignition Coil OEA for $20/each but not sure what brand these are. There are bunch of these out there at this price with no brand.
 
#69 ·
Wanted to report that I do feel a very noticable improvement in acceleration.

Prior to this, and after replacing the DISA which was suggested (and it was broken after inspecting it, that's also why I replaced it), I was also experiencing a 'bogging down, with burst of acceleration' when trying to accelerate from a stop. It didn't improve after the DISA. However, I don't have that issue now. The accelartion is pretty smooth. Unfortunately, the issue I have with miss is definitely less noticable, but its warmer today @10 degrees C and this is not when I have normally had the issue, its more pronounced when the weather starts to get colder.

In any event, I am pleased with the fuel filter replacement results. Will check out what happens the next cold day.
 
#72 ·
I went about replacing the injectors with these GB REMANUFACTURING from Bimmer Specialist. These are like Siemens originals rebuilt.
I followed this procedure http://www.bimmerfest.com/forums/showthread.php?p=6344800#post6344800, so will not write it up.

The only thing that I would add to the procedure is that after you release the pressure, you will still have gas in the fuel rail. When you remove injectors from front to back you will get more gas coming at the bottom end than than you think, so have your rags handy.

Because I had to take the rail off a second time, I disconnected the fuel pump and ran the engine to clear the gas out and there was less of it as a result.
 

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#73 ·
The entire R&R injector procedure is not that challenging, but this is not one of my favorites. While the GB Units looked, there was one that looked a bit pitted at top of the injector (by plug). It seemed to seat properly, but when I did a test run it was p**sing out gas :mad:.

I took it all off again, then checked the o-ring and that looked fine, but on the second try it did the same thing leaking.

On the third try I moved it and it was leaking without any pressure on the rail and not running so, I just put one of the old injectors back on. After that it was not leaking. I will need to send it back and wait for a new one to be sent :thumbdwn:. While I like online shopping the shipping back and forth can be a pain for these kinds of situations.

I won't be able to say if its the injectors resolve this until I replace the old one with the new one. However, if the problem was with one of the 5 that were removed it might be ok. I report back when its cold again.
 

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#75 ·
The miss was still present today when I started the car. While I have not been able to solve the rough start problem when cold, the acceleration and gas mileage has improved. I should be getting a new injector later this week so I will update then, but I am sure its likely not going to solve this problem.
 
#76 ·
Here's the latest. I received the replacement injector and much to my chagrin, after installing it the injector leaked!:mad: So, after replacing the upper o-ring thinking it might be the source of the problem, and various other troubleshooting, I ended up putting the old injector back on. I captured the troubleshooting here on this link http://www.bimmerfest.com/forums/showthread.php?t=587067&highlight=. Instead of spending another week waiting an messing around with a GB remanufactured injector, I ordered a new VDO one. Replaced it, without any issues. Now, I'll have to report back to see if there is any changes when it gets below 0.
 
#79 · (Edited)
Updated Recap of what has been done to solve, but still have miss:
New Plugs
New Intake boots upper and lower
New air filter
New DISA
New emission control air pump and valve

New Bosch Coils
New Fuel filter
New CCV
New valve cover gasket
New Injectors

VANOS - Beisian Procedure to replace rings
Checked for vacuum leaks, including behind intake and caps
Cleaned the MAF, did the unplug test and used MAF Cleaner
Cleaned the ICV
Cleaned the the throttle body
Checked for codes- none

Now some of the above in italics, I did b/c the broke or needed to be changed. There were some very noticeable acceleration improvements when I changed the fuel filter and injectors. DISA also improved this as well. I can't say I noticed much after doing the VANOS other than the RPMS stay a bit higher when started.
 
#87 ·
I have 2002 520i done 79K. Last night the battery went flat and got it replaced with new one. Early morning, the car started with vibrations at low RPM (~700) and after racing at 2000 rpm, i thought things will be smooth but, the engine was put off. I waited couple of mins and restarted the engine but vibrations at low rpm persists. AT high there is no vobrations but Iam scared to release the pedal as it may switch off again. I am getting no warning or fault indication while running. The weather is moist and cold (17C).

What could be the issue for engine to switch off and low rpm vibrations.
 
#90 ·
I documented this on another thread, but 3 of the GB remanufactured injectors I received developed leaks. I replaced them with new VDO ones, but it has been relatively mild to access the situation in cold weather. Once it is around -10C, I will be sure to report.
 
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