SOLVED: 2003 X5, 3.0l, runs rough, reset on restart?

[cmelkoni]

uppallnight,

Thanks for the suggestion. My scanner does allow me to check live data. Bank 1 has positive Long Term and negative Short Term. Bank 2 has the opposite. Here are some numbers at idle and 2500 RPM:

Idle
Bank 1 LT: +5.5
Bank 1 ST: 0.0 to -3.0
Bank 2 LT: -0.8
Bank 2 ST: 0.0 to +3.0

2500 RPM
Bank 1 LT: +5.5
Bank 1 ST: 0.0 to -3.0
Bank 2 LT: -0.8
Bank 2 ST: +4.0 to +7.0

What it looks like is that upon going to 2500 RPM, both Short Term trims change, but Bank 1 quickly goes back to the same value as at idle while Bank 2 stays more positive.

From your post, it looks like this is pointing to a vacuum leak. Would appreciate your opinion/direction.

[cmelkoni]

Another interesting point is that the TPS sensor doesn't seem to be acting as I would expect it to.

TPS is at 0.0% when at idle. When not moving (in neutral), I would expect the TPS % to smoothly follow the accelerator pedal as I step on it. Instead, a change doesn't register until I push the pedal halfway down and the RPM's are pretty high. If I peg the pedal, I can briefly see the TPS % in the 90's, but it is not steady.

I took the car out for a test drive and watched the TPS%. It does change and I can see it occasionally in double digits, but I couldn't see any pattern.

This may be just how the TPS operates on the E53 but I thought it was worthwhile to note.

[upallnight]

Originally Posted by cmelkoni

uppallnight,

Thanks for the suggestion. My scanner does allow me to check live data. Bank 1 has positive Long Term and negative Short Term. Bank 2 has the opposite. Here are some numbers at idle and 2500 RPM:

Idle
Bank 1 LT: +5.5
Bank 1 ST: 0.0 to -3.0
Bank 2 LT: -0.8
Bank 2 ST: 0.0 to +3.0

2500 RPM
Bank 1 LT: +5.5
Bank 1 ST: 0.0 to -3.0
Bank 2 LT: -0.8
Bank 2 ST: +4.0 to +7.0

What it looks like is that upon going to 2500 RPM, both Short Term trims change, but Bank 1 quickly goes back to the same value as at idle while Bank 2 stays more positive.

From your post, it looks like this is pointing to a vacuum leak. Would appreciate your opinion/direction.

One area that I would look at is the rubber bellow boot that connects the throttle body, Idle Control Valve to the MAF. The bellow portion of the boot that connects to the IAC normally tears. If you haven't replace it recently, take a look at that.

[cmelkoni]

Thanks. I will check that boot and other intake components for a leak as soon as I can.

Any thoughts on the TPS sensor? Live data of the Absolute TPS position just doesn't seem right to me. Again, here's what is happening:

TPS is at 0.0% when at idle. When not in gear, I would expect the TPS % to smoothly follow the accelerator pedal as I step on it. Instead, a change doesn't register until I push the pedal halfway down and the RPM's are pretty high, at which point the TPS % will be in the teens but not steady. If I peg the pedal, I can briefly see the TPS % in the 90's, but it jumps around.

I took the car out for a test drive and watched the TPS%. It does change and I can see it occasionally in double digits, but I couldn't see any linear pattern.

[StephenVA]

The signal you are reading is what is called a processed value. It will NOT give you a lab scope line wave/steps.

In order to get a true value of TPS readings you will need a lab scope. But there is an alternative. Just read it with the engine off but key on through the OBDC port with a scanner. It will put you in the ball park to see if it functions. When they fail the volt values jump all over so there usually no codes being set, just input the engine management systems can not comprehend so it does stupid stuff. Most shops choose the "when in doubt replace" methodology as it is after all 15 years old and only has a 100 thousand mile cycle life.....

If you purchase the BMW laptop software you can see the values live and any captured failures
Helpful?

[cmelkoni]

StephenVA,

Thanks for the reply. I believe what you are saying is that the "ABSLT TPS %" value from my Actron scanner when the car is running is not a real-time value but is processed. You therefore won't see the expected smooth transition from about 5% at idle to 90% WOT while the car is running. Correct?

I believe you are also saying that you can see the expected smooth transition if you scan with the key on/engine off. However, in this case, throttle must be manually actuated.

Please confirm above.

Yes, I do have BMW laptop software, DIS V57 with K-line cable. I just haven't installed and used it yet which I will do tonight.