2006 e53 3.0 hesitiation little to no power

mendes9 · #1 10-08-2014, 05:45 PM

Hello, while driving my x5 today I noticed that I had little to no throttle response and hesitation/engine hesitiation. It got so bad I was down to maybe 10 mph but I was able to barely make it home. It threw some codes that I was able to pull with my generic reader which were p0171,p0174 and p1515. I know what they are except for the p1515 which is I think a manufacture specific code only read with a better scanner.

My first thought is Mass Air Flow sensor.. I took it out and cleaned it, but it didn't look dirty. I thought maybe it's the transmission but putting the car into neutral did the same thing no change when it was happening. When it wouldn't accelerate I had put the pedal down almost to the floor at one point and the engine did accelerate at one point but I heard what sounded like a knock in the engine. For throwing lean codes in both banks, means to me possibly has to be some sort of sensor. These engines have individuals coil packs on each cylinder right ( I replaced the plugs around 60K miles, have 88K miles now) so the way the engine was hesitating it had to be more than one cylinder. Is there maybe some sort of central coil pack that controls all of them? Any suggestions would be welcome before I take it to the stealership.

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THE VEIN · #2 10-08-2014, 06:13 PM

p1515 is your throttle body. basically throttle body and gas pedal is out of sync

mendes9 · #3 10-08-2014, 06:14 PM

thank you, suggestions on possible fix?

THE VEIN · #4 10-08-2014, 06:33 PM

I'm sorry I don't think my answer is 100% correct. after some digging on Google I'm getting mixed answers to p1515

mendes9 · #5 10-08-2014, 09:29 PM

thanks.. not sure per my reading hesitiation on acceleration to the point of almost bogging down could be so many things.. TPS sensor, Vanos seals, O2 sensors, and the list goes on. For the p1515 error I see throttle body position error, or IAC idle are control valve. Unless someone has some suggestions throwing parts at it is not cheap and in the end I may just take into the dealer.

Takimo · #6 10-08-2014, 11:50 PM

poor/laggy acceleration is common vacuum leak

upallnight · #7 10-09-2014, 07:34 AM

Quote:

Originally Posted by Takimo

poor/laggy acceleration is common vacuum leak

BINGO!!!!

you have lean codes in both banks so it is something that can affect both banks.

The rubber boot that attaches the IAC and the throttle body would be the first place I look.

The DISA valve would be the second place I look. Careful with removing the DISA valve if the pin for the flap has come out you don't want to lose it in the intake manifold.

mendes9 · #8 10-10-2014, 11:06 PM

here we go.. I took out the DISA valve actually I tried.. stripped one of the dam torx screws and .. wound up breaking the DISA valve because of that torx screw. And the bad news is the DISA valve looked good to me, the valve moved the piston ok, and if I plugged the hole to test vacuum and let the flap go, it moved to a 45 deg position which should be good or so I read. Ordered the DISA valve $286 original BMW OUCH.. should get it Monday.

Looked at the intake boot to the throttle body and Idle control valve can't see any leaks on the boots.. any suggestions would be appreciated. I have a spare car so I'm trying to DIY before I take it to the dealer.

Again symptom is, car would start no issue, idle would be slightly rough but not much and if I accelerate I have no power hesitation and it will stall. Codes pulled were lean codes in both banks, the other code p1115, however, that was only pulled once, normally I turn it off idles sometimes rough and if I accelerate then hesitation, and it will stall. So it only registered these codes once. I'm finding conflicting information on what a P1515 means.

Could it be the mass air flow sensor? If I pull the electrical connector from the MAF and turn on the car I don't see much difference except idle is maybe a little different but if I accelerate it will stall again. If I pull the MAF sensor cable while the car is running, then the car dies right away and MAF code is recorded on OBD II tool. So is the MAF ok?

mendes9 · #9 10-12-2014, 03:09 PM

Well it's not looking good.. I took off the DISA as I said it looks good.. I took off the intake boot to the ICV and throttle body, was hoping to find a tear or hole nothing.. looks good. Is my idle control valve good not sure but I don't think it would cause these symptoms I cleaned both the throttle body and icv. While doing all this stripped a head on a t40 torx bolt.. took me a while to finally get that sorted. Why on earth they use t40 torx heads instead of some normal head I'll never know.. and apparently someone already ran into the same problem on my car probably the dealer for warranty work I had done a while back because one bolt wasn't t40 head it had a square head. I ordered a new DISA valve and intake throttle body rubber boot.. might as well replace it while I have it apart but mine looked fine.. parts ordered anyway.

I did a bunch of reading with others that had something similar to what I'm seeing and I'm down to possibly...

Oil level sensor (after I get the car together, I'll unplug that and see if it resolves the issue)
Cam shaft position sensor
throttle position sensor
Mass Air Flow sensor

Oil level sensor and cam shaft position sensor no issue in getting those replaced if I go that way.. but the throttle position sensor now would be the time to try that although that looks like it may require taking out the throttle body haven't seen any instructions on how to do that, but I'm not finding many people with that issue but who knows.

upallnight · #10 10-12-2014, 03:16 PM

When you pulled the DISA valve from the intake manifold, was it easy or did it require some work to get it out?

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