Power surges - continued

[MZWIE]

My car continues to have these nasty power surges. No codes so the dealers can't, won't do anything. The surges are totally random. No specific speed, RPM or anything repeatable.

So far I've done:

Plugs
Coil packs
Walnut blasting

A freind suggested that maybe there is something wrong with the throttle - Gas pedal unit or other sensor.

So I am looking for feedback and help to determine what I might ckeckout. Are there potentiometers in the throttle that may be going bad. Some other sensor that has input to that loop perhaps.

Oh yeah. It also does it with the Cruise on, which is why I am asking about another sensor perhaps.

[MZWIE]

bump

[MZWIE]

Few views but no suggestions.

[LDmc85]

Sounds to me like a boost issue, could be a plethora of other things. Are you running stock CP? If so that'd be the first thing to check.

[Dackelone]

Maybe some more info... N54 or N55 ? Manual, auto or DCT ? How many miles?

When you had the carbon cleaning - I assume at a dealer? And they replaced all the intake gaskets and did not reuse them? That could cause a vacuum leak.

You could get a OBDII dongle/bluetooth connector like this one...
http://www.amazon.com/gp/product/B00...?ie=UTF8&psc=1

...then use an app like "Torque" or "BmWhat" to check for codes(and clear them!) and also monitor the engine functions, like throttle position, vacuum, load, etc.

One thing that comes to mind is your spark plugs. A lot of people don't think spark plugs make any difference whether they are bought from BMW or a discount shop. But it does. The BMW sold ones are different in the internal ceramic design. I've read here on 1Addicts and on the e90forum that aftermarket plugs can cause drivability issues. Like ignition missing or surging. I would look into what spark plugs were used. Also N54 plugs are different from N55 plugs.

Another thing that comes to mind IF your engine is a N55 is the vanos bolts. Maybe your vanos unit is shifting the cam timing while cruising at a steady speed.

good luck,
Dackel

[MuNkY6913]

Originally Posted by Dackelone

Maybe some more info... N54 or N55 ? Manual, auto or DCT ? How many miles?

When you had the carbon cleaning - I assume at a dealer? And they replaced all the intake gaskets and did not reuse them? That could cause a vacuum leak.

You could get a OBDII dongle/bluetooth connector like this one...
http://www.amazon.com/gp/product/B00...?ie=UTF8&psc=1

...then use an app like "Torque" or "BmWhat" to check for codes(and clear them!) and also monitor the engine functions, like throttle position, vacuum, load, etc.

One thing that comes to mind is your spark plugs. A lot of people don't think spark plugs make any difference whether they are bought from BMW or a discount shop. But it does. The BMW sold ones are different in the internal ceramic design. I've read here on 1Addicts and on the e90forum that aftermarket plugs can cause drivability issues. Like ignition missing or surging. I would look into what spark plugs were used. Also N54 plugs are different from N55 plugs.

Another thing that comes to mind IF your engine is a N55 is the vanos bolts. Maybe your vanos unit is shifting the cam timing while cruising at a steady speed.

good luck,
Dackel

If you have a jb4, those programs don't work to monitor the engine. Already bought one and the apps. The apps won't read the obdII protocol because something with the jb4. It will connect with your phone but the programs won't connect to the car. They just keep trying and saying obdII protocol error. Heard there weren't any problems without the Jb4. Not worth it for me to take it out and try again. Atleast with stupid, crap iOS it doesn't work.

[MZWIE]

N54. AT. 103K. BMW Plugs. There are no codes which makes this incredibly difficult. Grabbing at straws now...