[seadragon]

Hi all,

This issue has been affecting my car for a while now, but cannot get to the bottom of it.

It is intermittent - can happen while driving or when pulling away.

Issue is that engine power is cut and engine is unresponsive. Remediated by taking foot off the gas pedal and pressing it again.

Engine is idling / revving smoothly and is serviced regularly.

Car is a 2005 E90 330i with automatic gearbox.

I tried resetting the automatic transmission adaptations.

Issue tends to happen more often when accelerating out of a corner.

However issue still happens when DSC is turned off using DSC button.

I suspect it is a faulty ABS sensor? But no ABS lights are on, and traction control light doesn't show when the engine power is cut.

Any ideas?

[seadragon]

Potentially same issue as described here:

https://www.bimmerforums.co.uk/threa...rottle.148266/

Need to have PUMA done, and potentially replace VVT motor?

[gbalthrop]

Originally Posted by seadragon

... Issue is that engine power is cut and engine is unresponsive. Remediated by taking foot off the gas pedal and pressing it again... 2005 E90 330i with automatic gearbox... Any ideas?

Ideas/Questions:
Don't GUESS -- DIAGNOSE

1) What warning lights appear when "engine power is cut"? SES? Trans? DSC?
2) What Fault Codes are read in all Modules, particularly DME, EGS, DSC?
3) What Make/Model Scan Tool or Diagnostic Software (INPA/ISTA) do you have available?
4) In US, large part chains such as Advance Auto, AutoZone, etc. read Fault Codes FREE. Anyone in Sydney AU?

Intermittent Electrical issues related to sensor inputs to DME CAN be diagnosed with proper Scan Tool or Diagnostic Software, but it takes knowledge of HOW systems work in your 330i, and proper test equipment.

If you have $10 DMM (Digital Multimeter) and you PROVIDE Last-7 Characters of your VIN, we can suggest some tests you can do. However Fault Codes are proper "starting point" for diagnosis of this type.
George

[seadragon]

Thanks gbalthrop

In answer to your q's:

1) No warning lights come on
2) There are no fault codes (I cleared codes recently after doing the ACC retrofit, will keep checking)
3) I have ISTA+ 4.32.15 and INPA 5.0.6
4) I can read codes with my OBD K-DCAN cable

[gbalthrop]

Originally Posted by seadragon

... Issue is that engine power is cut and engine is unresponsive. Remediated by taking foot off the gas pedal and pressing it again... Car is a 2005 E90 330i with automatic gearbox...

Originally Posted by seadragon

... No warning lights come on. There are no fault codes. I have ISTA+ 4.32.15 and INPA 5.0.6...

Then you have the "Equipment" you need to diagnose the situation. All you need is "A Plan".

If there are NO warning lights, such as DSC, EGS, DME(SES), then there are NO Sensor Signals received by those Modules which are Low/ High/ Implausible/ Missing. Same for lack of any Fault Codes in ANY Module.

If there WERE an issue with DSC/ABS or with EGS Transmission that was causing "Limp Mode" or loss of Engine power, the DME would be reacting to such fault AND, you would get one or more Warning Lights, along with Fault Code(s).

So that raises the question: What actual signals that are NOT "Implausible", etc. could the DME be receiving to cause it to "cut power" or become "unresponsive"??
I interpret those remarks to indicate that there is NO Engine Response to Accelerator Pedal position change unless you 'release the accelerator to "On Idle" position, and "start over" (don't have to STOP engine or "Reboot" DME)?

First things that come to mind:
1) Accelerator Pedal Module Signal, as received by DME is telling DME the pedal is at idle position (released, or "On Idle") when it is actually pressed.

2) VVT System has some "hiccup" which does NOT light SES lamp or set fault code, where Eccentric shaft returns to idle position until Accelerator Pedal signal goes to "On Idle", at which point it "Resets" and operates normally.

Since the issue is intermittent, & releasing Accelerator Pedal to "On Idle" position restores operation, that suggests it would be difficult to devise a way to test, even though either INPA or ISTA will show Live Data of Accelerator Pedal Module Signals received by DME, AND Eccentric Shaft Angle. The Obvious issue is being able to use INPA/ISTA to "Catch the bad actor -- 'IN THE ACT'".

So the questions NOW arise:
a) How often does 'acceleration out of corner' result in loss of power?
b) Does "taking foot off pedal" always restore Engine Response to Pedal Movement?

Obviously, you could begin with examination/cleaning of the Accelerator Pedal Module Connector Pins/ Sockets, but then you wouldn't know for sure that you had found/ corrected the problem. If you found water in Driver Footwell, pin corrosion, etc. that MIGHT be enough to provide confidence of "Fix".

Personally, if acceleration out of corner causes the issue at least 25% of the time, I would get a "co-pilot" who can observe computer screen showing Pedal Sensor Voltages and/or Eccentric Shaft angle, and see what changes when power is lost.

Finding a SAFE place to conduct those tests may present BIGGEST challenge. I'm sure there are other possible causes, so repeated testing after ruling out one or more causes may be required.

It is POSSIBLE that simple observation of either Pedal Sensor Voltage Values, Pedal Position % of max, or ESS Signal of shaft Angle, all as received by DME, with Ignition ON, Engine OFF, MAY provide some clues. That would be safer than highway testing, but may NOT reproduce the fault condition. In any event, I would do that FIRST, just to see what the INPA/ISTA Screens show, if nothing else. If you need "Menu Sequence"/ Path to Screens in either INPA/ ISTA, please advise.

Just some random thoughts, so please let us know what you find, and don't pull out in front of any trucks!
George

[Salad]

Hi I bought the car late last year had the exact same problem changed coils,plugs,vanos solenoids but the problem still existed then against my wishes my son did a rear muffler delete wanting a louder sound and it seems to have fixed the problem so I now think it had something to do with the butterfly flap in the driver's side exhaust tip which has a vacuum hose and solenoid to operate it which must of been faulty and causing the engine to be unresponsive at low revs.

[Three_thirty_I]

I had a 2005 E90 330i manual for many years, and it had this same issue, and it had been diagnosed and checked so many times, and countless stab in the dark parts replaced. I suspect most of the time it's a Valvetronic issue that happens from time to time. That one used to have low rpm stumbles or brief flat spot when setting off from 2nd or 3rd gear (at appropriate and not unreasonable speeds) occasionally, especially when accelerating a bit harder.

Originally Posted by Salad

Hi I bought the car late last year had the exact same problem changed coils,plugs,vanos solenoids but the problem still existed then against my wishes my son did a rear muffler delete wanting a louder sound and it seems to have fixed the problem so I now think it had something to do with the butterfly flap in the driver's side exhaust tip which has a vacuum hose and solenoid to operate it which must of been faulty and causing the engine to be unresponsive at low revs.

The exhaust flap is simple to control exhaust tone at lower speeds, and it's vacuum pump driven, not vacuum from the intake, so it won't be a vacuum leak to the engine itself. I actually tested this for a rattle noise from the engine that I was hearing by disconnecting the cable to the solenoid actuator, and it made zero difference to the rattle noise and I still felt the occasional stumble.

[Salad]

Originally Posted by seadragon

Hi all,

This issue has been affecting my car for a while now, but cannot get to the bottom of it.

It is intermittent - can happen while driving or when pulling away.

Issue is that engine power is cut and engine is unresponsive. Remediated by taking foot off the gas pedal and pressing it again.

Engine is idling / revving smoothly and is serviced regularly.

Car is a 2005 E90 330i with automatic gearbox.

I tried resetting the automatic transmission adaptations.

Issue tends to happen more often when accelerating out of a corner.

However issue still happens when DSC is turned off using DSC button.

I suspect it is a faulty ABS sensor? But no ABS lights are on, and traction control light doesn't show when the engine power is cut.

Any ideas?

I've got the same model car with auto and have had the exact same problem as you explain do you still have the car and if so have you fixed the loss of power problem?