E46 M3 throttle hesitation when accelerating from a dead stop

Spooks · Sun, Sep-05-2010, 10:39:38 PM

For about a month now I have been having issues when accelerating from a dead stop or from a very slow roll. Basically what happens is the car feels like its fuel starved and starts to hesitate. I've read on other forums with similar symptoms, and people have described the motion as "bucking" or "jerking". Don't get it confused with the bucking sensation when you first start to drive an SMG and drive it like an automatic, this is not the case. The bucking motion is not as violent and happens ALL the time. All I know is that its hard to run it against the prick that is trying me at a red light. Once I give it gas, it "hiccups" two or three times until it smooths out and flies. The problem exist in all SMG modes w/ or w/o the DSC. I have also realized that there is a delay in my speedometer. When I start to accelerate, the needle does not move until my rpm's get to around 2000+. I don't know if this has anything to do with it or not.

I have tried cleaning the MAF sensor and throttle body, but still have the same symptoms. My spark plugs and O2 sensors are about a year old. I have a brand new clutch pack and flywheel from a previous rear gasket leak that saturated my clutch pack. I really have no clue to what this can be. Any suggestions?

EricSMG · Sun, Sep-05-2010, 11:22:57 PM

I had the same thing happen... exactly the same... and it was a small short inside the MAF. New MAF = no more hesitation.

Spooks · Sun, Sep-05-2010, 11:31:24 PM

Thanks for the reply! So you had the same symptoms and it was a short in the MAF...hmmm. How was the short diagnosed? The thing is, Im not receiving any codes at all. Could be it though.

JREEVES197 · Mon, Sep-06-2010, 12:16:50 AM

check the coils too.

EricSMG · Mon, Sep-06-2010, 12:52:56 AM

Quote:

Originally Posted by Spooks

Thanks for the reply! So you had the same symptoms and it was a short in the MAF...hmmm. How was the short diagnosed? The thing is, Im not receiving any codes at all. Could be it though.

Well, the dealer was able to pull a code even though there wasn't a CEL (not all codes throw the light). I sorta got lucky, but it did cure the problem.

Spooks · Mon, Sep-06-2010, 01:59:52 AM

What are the symptoms of bad coils? I'm starting to think that it might be the fuel pump.

Spooks · Mon, Sep-06-2010, 02:13:04 AM

EricSMG, did your speedometer also have a delay?? If your symptoms are exactly the same, then I guess it is a bad MAF sensor.

Spooks · Wed, Sep-15-2010, 01:10:25 AM

Haven't had any convincing feedback. Can anyone help me diagnosis my problem??

robbieracer · Fri, Sep-17-2010, 07:45:06 PM

I'm insterested to hear more on this too. Mine started a couple weeks ago but mine happens a little later when rolling on the throttle. It's most noticable in 5th gear, but can also feel it in 4th when I let off on the gas to coast then push the throttle again. I have a 6MT and no MAF. I suspected the fuel pump and changed that out yesterday, but that didn't fix it. I was monitoring my throttle position via OBD II port and it didn't seem accurate and wondering if it's TPS. To me, it seems more fuel or spark related but not sure. I have 14,000 on the fuel filter and I don't think it's that. I'm at a loss and not getting any codes, I have the Autoenginuity.

Sun, Sep-05-2010, 10:39:38 PM	#1
Spooks Registered User Join Date: Sep 2010 Posts: 46 Reputation: 0 Location: Miami, FL	E46 M3 throttle hesitation when accelerating from a dead stop For about a month now I have been having issues when accelerating from a dead stop or from a very slow roll. Basically what happens is the car feels like its fuel starved and starts to hesitate. I've read on other forums with similar symptoms, and people have described the motion as "bucking" or "jerking". Don't get it confused with the bucking sensation when you first start to drive an SMG and drive it like an automatic, this is not the case. The bucking motion is not as violent and happens ALL the time. All I know is that its hard to run it against the prick that is trying me at a red light. Once I give it gas, it "hiccups" two or three times until it smooths out and flies. The problem exist in all SMG modes w/ or w/o the DSC. I have also realized that there is a delay in my speedometer. When I start to accelerate, the needle does not move until my rpm's get to around 2000+. I don't know if this has anything to do with it or not. I have tried cleaning the MAF sensor and throttle body, but still have the same symptoms. My spark plugs and O2 sensors are about a year old. I have a brand new clutch pack and flywheel from a previous rear gasket leak that saturated my clutch pack. I really have no clue to what this can be. Any suggestions? __________________ 2004 Alpine White w/ Imola Red interior/ CSL interior/ Koni/ H&R/ aFe intake/ Umnizta Last edited by Spooks; Wed, Sep-15-2010 at 01:08:47 AM.

Sun, Sep-05-2010, 11:22:57 PM	#2
EricSMG 30 something Join Date: Nov 2008 Posts: 6,557 Reputation: 0 Location: San Diego	I had the same thing happen... exactly the same... and it was a small short inside the MAF. New MAF = no more hesitation. __________________ *'04 46M 6MT \|\| '01 330Ci 5MT*

Sun, Sep-05-2010, 11:31:24 PM	#3
Spooks Registered User Join Date: Sep 2010 Posts: 46 Reputation: 0 Location: Miami, FL	Thanks for the reply! So you had the same symptoms and it was a short in the MAF...hmmm. How was the short diagnosed? The thing is, Im not receiving any codes at all. Could be it though. __________________ 2004 Alpine White w/ Imola Red interior/ CSL interior/ Koni/ H&R/ aFe intake/ Umnizta

Mon, Sep-06-2010, 01:59:52 AM	#6
Spooks Registered User Join Date: Sep 2010 Posts: 46 Reputation: 0 Location: Miami, FL	What are the symptoms of bad coils? I'm starting to think that it might be the fuel pump. __________________ 2004 Alpine White w/ Imola Red interior/ CSL interior/ Koni/ H&R/ aFe intake/ Umnizta

Mon, Sep-06-2010, 02:13:04 AM	#7
Spooks Registered User Join Date: Sep 2010 Posts: 46 Reputation: 0 Location: Miami, FL	EricSMG, did your speedometer also have a delay?? If your symptoms are exactly the same, then I guess it is a bad MAF sensor. __________________ 2004 Alpine White w/ Imola Red interior/ CSL interior/ Koni/ H&R/ aFe intake/ Umnizta

Mon, Sep-06-2010, 12:16:50 AM	#4
JREEVES197 Registered User Join Date: Aug 2010 Posts: 116 Reputation: 0	check the coils too.

Wed, Sep-15-2010, 01:10:25 AM	#8
Spooks Registered User Join Date: Sep 2010 Posts: 46 Reputation: 0 Location: Miami, FL	Haven't had any convincing feedback. Can anyone help me diagnosis my problem?? __________________ 2004 Alpine White w/ Imola Red interior/ CSL interior/ Koni/ H&R/ aFe intake/ Umnizta

Fri, Sep-17-2010, 07:45:06 PM	#9
robbieracer Registered User Join Date: Dec 2008 Posts: 375 In the garage: '03 BMW M3 Reputation: 0 Location: Sacramento	I'm insterested to hear more on this too. Mine started a couple weeks ago but mine happens a little later when rolling on the throttle. It's most noticable in 5th gear, but can also feel it in 4th when I let off on the gas to coast then push the throttle again. I have a 6MT and no MAF. I suspected the fuel pump and changed that out yesterday, but that didn't fix it. I was monitoring my throttle position via OBD II port and it didn't seem accurate and wondering if it's TPS. To me, it seems more fuel or spark related but not sure. I have 14,000 on the fuel filter and I don't think it's that. I'm at a loss and not getting any codes, I have the Autoenginuity. __________________ ESS VT2-500 \| Tein S/Koni \| Focal/Zapco \| VAC Motorsports High Flow Oil Pump \| M5 LSD

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