E39 530 Acceleration/engine problem

[pomertronix]

Hi All. Long time reader, first time poster.
I've got a 2001 530i E39 and ever since I bought it (around 2 years ago) it's always felt a bit underpowered.
The main problem I have however, is that if I leave the car without running it for more than a day it has real trouble running again. It will start fine (electrically ok) but it'll struggle to idle smoothly and will shake quite violently for a while. Worse though if you put your foot down with a little bit of intent it will start to splutter and cough and the idle becomes incredibly rough before the engine cuts out entirely. It will often start again but as soon as you apply the accelerator pedal (even gently) it cuts out. It then won't run again for at least 12 hours or so. It's running again now but feels really sluggish and I'm not sure how much power it has.
The first time this problem occurred (with the car breaking down on the side of the road) was around 6 months ago and I had it towed to the mechanic. They told me when they tried to run it (the next day) it started up fine but there were some error codes coming up for what I think he said were the cylinder coils - sorry that's beyond my technical knowledge. He seemed to think this wasn't the cause but given it wasn't very expensive I opted to replace a few of these coils anyway and the problem seemed to be resolved.
I'm curious to know whether anyone else with this engine has experienced the same problem and if so how they fixed it.
Cheers.

[bE34ST]

I had a similar issue when one of my ignition coils failed. Rough idle, and loss of power when I put my foot in it.

[Das Leg]

Got myself a 530i a week ago, and it also feels and is in fact underpowered since my 523i is faster. Had the codes scanned and got P0014, which is the camshaft sensor on one bank, replaced both last night with BMW OEM units at $280 only to realise at first start up that the problem is still there. Mine idles a little rough, no violent shaking and such. Starts just fine and drives well, but has NO punch what so ever.

Will leave the car to the BMW-dealership next week and have them read the codes to see if they spot something different.

But OP and bE34ST, seems like the coils can be one thing to look into aswell?. I just refuse to rebuild the vanos on a car that cost me $1700 to buy, since I can't do it myself, will sell it on and buy another one if this gets too expensive.

[RuskiE39]

Vanos comes to mind when you talk about being low on power, obviously if you have codes stored i would start there.

[WBAD530i]

My '01 530i had a lack of power when I first got it. From launch you could push the pedal, no response, then all of a sudden it would just jerk and start going. This is because the Vanos seals were shot. Oil was passing by them, but when you did hit the 3k RPM mark, it would force the pistons and start going. I replaced the seals, and now it has regained the low end torque. Flooring it from launch will put you back in the seat, and every gear picks up more speed. Mine is an auto and driving in Sport mode is much more satisfying. I love my i6 now. Feels like a brand new car with the seals being changed.

Before changing my seals...on a cold start it would immediately idle at around 500-600 RPM. After changing the seals it started idling at 900-1100 RPM on a cold start. This occurs for about a minute, and then it dials down to 500-600 RPM. I think this high idle is how the car is supposed to behave when its warming up from a cold start. I was not aware of this when I first got it. That's why changing the seals is such a huge improvement. It's a fun job to do. Let's you get a little intimate with your car, learn about the top end a little. I also changed the timing chain tensioner, but it was barely worn to begin with. Doing this same time as Vanos seals I don't really know if it had an impact. My i6 ticks on a cold start, and periodically while it runs because it was neglected by the PO, and I use M1 0w-40 which apparently makes the engine a little noisy compared to using Castrol...IDK. The lifters are sticky I guess. Doesn't effect performance though.

OP, change out all 6 of your plugs with NGK BKR6EQUP. If this does not solve the issues you need to replace the coils as stated above. It's the thing that sits on top of each spark plug. These can be pricey, and I don't recommend changing just one or two. Change them all, buy the same OE brand. You will not regret it. Do your vanos seals as well. I can promise you that you will fall in love with the car all over again.

Don't let a mechanic touch your car for this, these jobs are so easy. You gain so much satisfaction out of completing the jobs yourself. There is so much information on these forums to guide you through the process. All the members on here will help you through any snags along the way.

[pomertronix]

Appreciate the responses from all concerned.
In regards to WBAD530i's comments; honestly it's never had any low-end torque, always felt pretty gutless down low as opposed to a Subaru H-6 that I also tested which kept spinning all 4 wheels every time I accelerated! However it does idle at around 800-1200 rpm from cold before moving to the 400-600 mark once warmed up a touch - the difference in revs could be due to differences in fuel quality between US and Australia. My major concern remains however; why it struggles so much after sitting for a day or two.
Given I don't always drive to work daily it's a problem and any further insight would be much appreciated.
Cheers.

[WBAD530i]

Appreciate the responses from all concerned.
In regards to WBAD530i's comments; honestly it's never had any low-end torque, always felt pretty gutless down low as opposed to a Subaru H-6 that I also tested which kept spinning all 4 wheels every time I accelerated! However it does idle at around 800-1200 rpm from cold before moving to the 400-600 mark once warmed up a touch - the difference in revs could be due to differences in fuel quality between US and Australia. My major concern remains however; why it struggles so much after sitting for a day or two.
Given I don't always drive to work daily it's a problem and any further insight would be much appreciated.
Cheers.

The only thing that really comes to mind is fuel delivery. Could be any of the following:

Soft failing fuel pump that doesn't function 100% until warmed up.
Clogged fuel filter.
Junk in your gas tank that is clogging any of the lines from Tank to fuel pump to filter to injectors.

If you can rule all these out then I would suggest running a few bottles of Techron through the system with some ethanol free premium gas if you can find it. Otherwise just always run premium and put Techron in the tank until you see these symptoms disappear. This won't effect performance at all. It will ensure everythings cleaned out though. Could always just change out the fuel filter for the hell of it. I need to do mine, but no symptoms. I just like to do preventative stuff to learn about the car and have peace of mind. Gotta keep my only car/DD running or I'm screwed.