Surge, Occilation..HELP

cent778 · 05-03-2010, 10:19 AM

I'm experiencing surge, oscillation at low rpm (1500-1800rpm) when having a constant throttle pressure. This occurs with cruise control active as well.

I had some RR O2 sims that threw 2C7F, 2C6A, 2C74 codes. Had them replaced with BMS v3 sims (default setting) and traveled approx 40km, no codes so far.
I presumed the downpipe fix would rectify this problem but it hasn't.

Can any one chime in on what I can do to rectify this problem?
It's not tune related, as I'm experiencing this with no tune, SSTT and now GIAC.
BWM techs are useless, they have had the car on several occasions and say they can not replicate the problem. The car comes back with no surge then after a few weeks its back again.

Thanks in advance

cent778 · 05-04-2010, 01:35 AM

Anyone?

enrita · 05-04-2010, 02:49 AM

if you are still getting codes set it stronger. 1/8 turn counter clockwise with wires facing away from you.

cent778 · 05-04-2010, 09:26 AM

I think there is a slight misunderstanding. The BMS downpipe fix v3 work perfect, I'm not getting any cat related codes as of now.

Problem is, I'm still experiencing surge/oscillation at low rpm.
At any set speed (60,70, 80k/ph) my revs will hunt up and down approx 100rpm.
This combined with a complete free flow exhaust really magnifies the situation.
Feels as tho grandma is driving and can't help but throttle on, lift and throttle on.
BT scanner has not shown any codes which leaves me dumb found

Mike@N54Tuning.com · 05-04-2010, 09:35 AM

What tune are you running now? If you want to try the jb3 we should be able to get a map made for you that should fix the problem.

Have you tried sourcing your gas from another place just to rule out some funky gas problem?

Mike

Mr. 5 · 05-04-2010, 09:43 AM

Are the surges happening when cruising or when WOT?

cent778 · 05-04-2010, 10:00 AM

Euro Ron 98 (US 93) is what I always use. As for service station I normally alternate between 2 stations depending which area I'm in at the time.
I may have to try an different station, with a higher turnover rate just to delete that possibility out of the equation (bad gas).

Tune wise I'm on GIAC S1. Not planning to switch tunes at present, especially when I haven't sampled GIAC S2 map.
I've only heard of one local guy running a BMS tune but haven't been able to track him down.
Prefer not to post his plates No. but he had his car dynoed at House of power. So if you're reading this please pm for a meet up along with a few Procede guys

cent778 · 05-04-2010, 10:06 AM

Surge is occurring at cruise from what I gather. WOT and the the car pulls hard and surge is not evident.
I don't have a boost gauge so I cant really say for sure.

05-03-2010, 10:19 AM	#1
cent778 Private 1 Rep 82 Posts Drives: e92 335 Join Date: Apr 2009 Location: Perth iTrader: (0)	Surge, Occilation..HELP I'm experiencing surge, oscillation at low rpm (1500-1800rpm) when having a constant throttle pressure. This occurs with cruise control active as well. I had some RR O2 sims that threw 2C7F, 2C6A, 2C74 codes. Had them replaced with BMS v3 sims (default setting) and traveled approx 40km, no codes so far. I presumed the downpipe fix would rectify this problem but it hasn't. Can any one chime in on what I can do to rectify this problem? It's not tune related, as I'm experiencing this with no tune, SSTT and now GIAC. BWM techs are useless, they have had the car on several occasions and say they can not replicate the problem. The car comes back with no surge then after a few weeks its back again. Thanks in advance
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05-04-2010, 01:35 AM	#2
cent778 Private 1 Rep 82 Posts Drives: e92 335 Join Date: Apr 2009 Location: Perth iTrader: (0)	Bump Anyone?
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05-04-2010, 02:49 AM	#3
enrita Major General 161 Rep 7,377 Posts Drives: 335i - Big turbos Join Date: Sep 2008 Location: Italian in Sweden iTrader: (0)	if you are still getting codes set it stronger. 1/8 turn counter clockwise with wires facing away from you. __________________ 07 335i AT - MOTIV 750 - MHD E85 BMS flash - BMS PI - JB4G5 - Okada Coils - NGK 5992 Plugs - Helix IC - Snow Stg. 3 - Stett CP - Custom midpipes with 100 HJS Cats - Bastuck Quad - PSS10 - QUAIFE LSD - BMS OCC - Forge DVs - AR OC - ALCON BBK - M3 Chassi - Dinan CP - Velocity M rear Toe arms - Advan RZ-DF - LUX H8 - Level 10 AT upgrade
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05-04-2010, 09:26 AM	#4
cent778 Private 1 Rep 82 Posts Drives: e92 335 Join Date: Apr 2009 Location: Perth iTrader: (0)	I think there is a slight misunderstanding. The BMS downpipe fix v3 work perfect, I'm not getting any cat related codes as of now. Problem is, I'm still experiencing surge/oscillation at low rpm. At any set speed (60,70, 80k/ph) my revs will hunt up and down approx 100rpm. This combined with a complete free flow exhaust really magnifies the situation. Feels as tho grandma is driving and can't help but throttle on, lift and throttle on. BT scanner has not shown any codes which leaves me dumb found
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05-04-2010, 09:35 AM	#5
Mike@N54Tuning.com Joint Chiefs of Staff 4919 Rep 115,980 Posts Drives: 2007 335i, 2015 M3 Join Date: Dec 2008 Location: N54tuning.com iTrader: (89)	What tune are you running now? If you want to try the jb3 we should be able to get a map made for you that should fix the problem. Have you tried sourcing your gas from another place just to rule out some funky gas problem? Mike Last edited by Mike@N54Tuning.com; 05-04-2010 at 09:47 AM..
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05-04-2010, 09:43 AM	#6
Mr. 5 Modder Raider 755 Rep 8,633 Posts Drives: M3 Join Date: Apr 2007 Location: Surf City, HB iTrader: (31) Garage List 2007 e90 335i [8.00]	Are the surges happening when cruising or when WOT? __________________ e36 M3 Coupe, e36 325i Sedan e90 335i--SOLD Best 60-130-------------9.15 Seconds------------------WWW.MR5RACING.COM
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05-04-2010, 10:00 AM	#7
cent778 Private 1 Rep 82 Posts Drives: e92 335 Join Date: Apr 2009 Location: Perth iTrader: (0)	Euro Ron 98 (US 93) is what I always use. As for service station I normally alternate between 2 stations depending which area I'm in at the time. I may have to try an different station, with a higher turnover rate just to delete that possibility out of the equation (bad gas). Tune wise I'm on GIAC S1. Not planning to switch tunes at present, especially when I haven't sampled GIAC S2 map. I've only heard of one local guy running a BMS tune but haven't been able to track him down. Prefer not to post his plates No. but he had his car dynoed at House of power. So if you're reading this please pm for a meet up along with a few Procede guys
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05-04-2010, 10:06 AM	#8
cent778 Private 1 Rep 82 Posts Drives: e92 335 Join Date: Apr 2009 Location: Perth iTrader: (0)	Surge is occurring at cruise from what I gather. WOT and the the car pulls hard and surge is not evident. I don't have a boost gauge so I cant really say for sure. Last edited by cent778; 05-04-2010 at 10:28 AM..
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