Stumbling when cruising

Redrkt503 · 07-31-2012, 07:56 AM

I just had this problem arise last night on a long drive home. I was in 6th gear at 80mph cruise control on and all of the sudden the rpm's just dropped to about 1300 and then went back to normal, this happened about 7 other times but wasn't happening under WOT, it also happened once when I was sitting at a light, I am not having any startup problems as far as long cranking etc, it is just when cruising... Any help would be appreciated

JamesM3M5 · 07-31-2012, 08:56 AM

Got any codes?

marv85 · 07-31-2012, 10:04 AM

+1 codes would be very helpful at this point

NjRep335i · 07-31-2012, 11:28 AM

I had similar issues and did the following maintenance.

Cleaned Vanos Solenoid
Cleaned Intake Valves
Changed Spark Plugs

Since I had planned to do the Intake valves everything else was pretty accessible. The car runs smooth now except for the wastegate rattle which is another weekend battle.

JamesM3M5 · 07-31-2012, 01:08 PM

Quote:

Originally Posted by NjRep335i

Since I had planned to do the Intake valves everything else was pretty accessible. The car runs smooth now except for the wastegate rattle which is another weekend battle.

I was able to adjust the front wastegate with the turbo still mounted to the engine, only had to drain the coolant (needed to be replaced, anyway) and remove the WP/thermostat and intercooler. Took me about 5 hours on a lift with a cool engine.

Redrkt503 · 08-02-2012, 04:24 PM

Codes throw: 2C7F, 2C6A and 2A94

Redrkt503 · 08-02-2012, 04:25 PM

The car has 98,000 miles

barrettm · 08-02-2012, 04:52 PM

Quote:

Originally Posted by zanelefko

Codes throw: 2C7F, 2C6A and 2A94

2c6a lambda probe after catalytic reversed
2c7e lambda probe after catalytic converter trim control
Sounds like your after cat O2 sensors swapped. Grey wire short dp, black wire long dp.
2a94- crack shaft pos sensor

JamesM3M5 · 08-02-2012, 05:00 PM

2C7F = Lambda probe behind catalytic converter 2, trim control
2C6A = Lambda probe behind catalytic converter, muddled (inverted)
2A94 = Crankshaft sensor, signal

Try clearing all your codes, and maybe reloading the map and firmware in the JB4 before trying to replace parts.

JamesM3M5 · 08-02-2012, 05:01 PM

Damn, you beat me to it!

Redrkt503 · 08-02-2012, 08:18 PM

Cleared the codes they came back, my car has been running great, mechanic said the codes from the 02 sensors are probably from downpipes, I'm
Going to replace crankshaft sensor tomorrow.

jpirelli · 11-07-2012, 08:16 PM

I'm getting 2C7F only. Car was running fine until recently. What could it be?

07-31-2012, 07:56 AM	#1
Redrkt503 Lieutenant 31 Rep 439 Posts Drives: E92 335is Join Date: Jan 2012 Location: Ft. Lauderdale, FL iTrader: (0)	Stumbling when cruising I just had this problem arise last night on a long drive home. I was in 6th gear at 80mph cruise control on and all of the sudden the rpm's just dropped to about 1300 and then went back to normal, this happened about 7 other times but wasn't happening under WOT, it also happened once when I was sitting at a light, I am not having any startup problems as far as long cranking etc, it is just when cruising... Any help would be appreciated __________________ 2011 335is "Redrkt" 6 MT DocRace 6266 Single Turbo - Fuel it stage 3 LPFP - Fuel it PI - spec stage 3+ clutch - mfactory SM flywheel - 100% E85 - VRSF 7.5" intercooler - VRSF charge pipe w/ HKS BOV - JB4 - MHD back end flash 768 whp 695 ft lbs - E85 - 32PSI
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07-31-2012, 08:56 AM	#2
JamesM3M5 Some dude 91 Rep 1,780 Posts Drives: E92 335i Join Date: Sep 2011 Location: Northern VA iTrader: (0)	Got any codes? __________________ RRT E92 335i/6MT with stuff and things
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07-31-2012, 10:04 AM	#3
marv85 Colonel 70 Rep 2,626 Posts Drives: '07 E92 335i MT Join Date: Jun 2010 Location: Bay Area iTrader: (7)	+1 codes would be very helpful at this point __________________ '07 E92 335i 6MT- HP650, inlets/outlets, ER FMIC, VRSF CP, LPFP stg2, CSF rad, 'is Aux rad, ER OC, Ohlins, M control arms, eibach front sway bar. '05 C55 AMG SOLD - '22 Tesla M3P \| '10 E92 335i M, 6MT COBB, FBO, st2 LPFP, Mfactory LSD \| '07 E90 335i, PTF COBB E50, FBO, HFS4
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07-31-2012, 11:28 AM	#4
NjRep335i Private 0 Rep 70 Posts Drives: 335i Join Date: Nov 2011 Location: United States iTrader: (0)	I had similar issues and did the following maintenance. Cleaned Vanos Solenoid Cleaned Intake Valves Changed Spark Plugs Since I had planned to do the Intake valves everything else was pretty accessible. The car runs smooth now except for the wastegate rattle which is another weekend battle.
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08-02-2012, 04:24 PM	#6
Redrkt503 Lieutenant 31 Rep 439 Posts Drives: E92 335is Join Date: Jan 2012 Location: Ft. Lauderdale, FL iTrader: (0)	Codes throw: 2C7F, 2C6A and 2A94 __________________ 2011 335is "Redrkt" 6 MT DocRace 6266 Single Turbo - Fuel it stage 3 LPFP - Fuel it PI - spec stage 3+ clutch - mfactory SM flywheel - 100% E85 - VRSF 7.5" intercooler - VRSF charge pipe w/ HKS BOV - JB4 - MHD back end flash 768 whp 695 ft lbs - E85 - 32PSI
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08-02-2012, 04:25 PM	#7
Redrkt503 Lieutenant 31 Rep 439 Posts Drives: E92 335is Join Date: Jan 2012 Location: Ft. Lauderdale, FL iTrader: (0)	The car has 98,000 miles __________________ 2011 335is "Redrkt" 6 MT DocRace 6266 Single Turbo - Fuel it stage 3 LPFP - Fuel it PI - spec stage 3+ clutch - mfactory SM flywheel - 100% E85 - VRSF 7.5" intercooler - VRSF charge pipe w/ HKS BOV - JB4 - MHD back end flash 768 whp 695 ft lbs - E85 - 32PSI
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08-02-2012, 05:00 PM	#9
JamesM3M5 Some dude 91 Rep 1,780 Posts Drives: E92 335i Join Date: Sep 2011 Location: Northern VA iTrader: (0)	2C7F = Lambda probe behind catalytic converter 2, trim control 2C6A = Lambda probe behind catalytic converter, muddled (inverted) 2A94 = Crankshaft sensor, signal Try clearing all your codes, and maybe reloading the map and firmware in the JB4 before trying to replace parts. __________________ RRT E92 335i/6MT with stuff and things
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08-02-2012, 05:01 PM	#10
JamesM3M5 Some dude 91 Rep 1,780 Posts Drives: E92 335i Join Date: Sep 2011 Location: Northern VA iTrader: (0)	Damn, you beat me to it! __________________ RRT E92 335i/6MT with stuff and things
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08-02-2012, 08:18 PM	#11
Redrkt503 Lieutenant 31 Rep 439 Posts Drives: E92 335is Join Date: Jan 2012 Location: Ft. Lauderdale, FL iTrader: (0)	Cleared the codes they came back, my car has been running great, mechanic said the codes from the 02 sensors are probably from downpipes, I'm Going to replace crankshaft sensor tomorrow. __________________ 2011 335is "Redrkt" 6 MT DocRace 6266 Single Turbo - Fuel it stage 3 LPFP - Fuel it PI - spec stage 3+ clutch - mfactory SM flywheel - 100% E85 - VRSF 7.5" intercooler - VRSF charge pipe w/ HKS BOV - JB4 - MHD back end flash 768 whp 695 ft lbs - E85 - 32PSI
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11-07-2012, 08:16 PM	#12
jpirelli Power is nothing without control 33 Rep 762 Posts Drives: E90 + E92 Join Date: Apr 2009 Location: Southeast/Southwest iTrader: (3)	I'm getting 2C7F only. Car was running fine until recently. What could it be?
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