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Discussion Starter · #1 ·
First off my car feels slow... took it to a tech and he said it is running lean. I fell a bit of lag in first gear and second. Now 3rd gear is where I really feel the lag... also... on a pull the car will go into limp mode around 6,500 RMP before red line in 3rd gear. In 4th it will go into limp mode on a pull around 5,000 - 5,500. Only had 1 SES which was last night and the peak codes were : Table 18, AF, C4, C6, CC and so on with the misfires. The car also misfires on warmup for the first 60 or so seconds when applying the throttle in any gear at any RPM... kind of lunges on warmup.

Any thoughts? MAF? CAM SENSORS?

Im a bit frustrated because I just got the car and it feels really slow. I sold a E46 M3 and this thing feels like a 540 compared to my M3.

Aaron
 

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First off my car feels slow... took it to a tech and he said it is running lean. I fell a bit of lag in first gear and second. Now 3rd gear is where I really feel the lag... also... on a pull the car will go into limp mode around 6,500 RMP before red line in 3rd gear. In 4th it will go into limp mode on a pull around 5,000 - 5,500. Only had 1 SES which was last night and the peak codes were : Table 18, AF, C4, C6, CC and so on with the misfires. The car also misfires on warmup for the first 60 or so seconds when applying the throttle in any gear at any RPM... kind of lunges on warmup.

Any thoughts? MAF? CAM SENSORS?

Im a bit frustrated because I just got the car and it feels really slow. I sold a E46 M3 and this thing feels like a 540 compared to my M3.

Aaron
If the tech could determine it was running lean, why couldn't he helped pinpoint the cause?

I would not think CPS, it affects timing, not mixture. MAF would definitely be a suspect, a known wear item. Cheap check is to spray with MAF cleaner. If you notice any improvement, time to replace.

Also check fuel pump and more importantly fuel filter. Low flow could affect high end performance, although if the lean reading was at idle, I would think more fuel filter and not fuel pump.

Regards,
Jerry
 

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MAF's - 90% given .. so many posts about the limp mode.

My car feels sluggish and every so often in traffic or driving the engine "looses" power and runs rough for about a min just to re-gain the power and drive normally. I reset SES light couple days ago, today it lost power and SES light came on and then i regained power. I ordered new MAF's yesterday, will see how that goes.
 

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First off my car feels slow... took it to a tech and he said it is running lean. I fell a bit of lag in first gear and second. Now 3rd gear is where I really feel the lag... also... on a pull the car will go into limp mode around 6,500 RMP before red line in 3rd gear. In 4th it will go into limp mode on a pull around 5,000 - 5,500. Only had 1 SES which was last night and the peak codes were : Table 18, AF, C4, C6, CC and so on with the misfires. The car also misfires on warmup for the first 60 or so seconds when applying the throttle in any gear at any RPM... kind of lunges on warmup.

Any thoughts? MAF? CAM SENSORS?

Im a bit frustrated because I just got the car and it feels really slow. I sold a E46 M3 and this thing feels like a 540 compared to my M3.

Aaron
Another Washingtonian :blabla: My car had symptoms similar to yours, the short story:

Got my Beast about a month ago, at which point it felt really strong. About 2 weeks after I had it, I had a noticeable decrease in acceleration, esp. in lower gears, but no SES light. My initial GUT feeling? (important) Bad MAFs. So I took the sage advice from this board and cleaned the MAFs with some CRC MAF cleaner, but I didn't see any improvement. I took it to BMW of Bellevue and had the foreman drive it. His suggestion? Bad tank of gas - run some Chevron + Techron through it. I was going to do that, but I started getting the SAME symptoms you had:

Rev Hunting
Lunging in 1st/2nd
A misfire or two
Trouble accelerating past 60 MPH or so (lag)

Finally got the SES light, so I nervously drove it into the BMW/Bellevue dealer. They ran diagnostics. The verdict? Bad MAFs. There were other codes showing up but they were MAF-related. Should have listened to my instincts. Luckily my aftermarket warranty covered both the diagnostics + MAF hardware. Good thing b/c they wanted $1200 for parts and labor.:eek:oohhh: My next order of business is to:

1) Order a spare set of MAFs.
2) Order a Peake reader.

Lesson learned?
Listen to the guys on this board, they know what they are talking about.
 

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Another Washingtonian :blabla: My car had symptoms similar to yours, the short story:

Got my Beast about a month ago, at which point it felt really strong. About 2 weeks after I had it, I had a noticeable decrease in acceleration, esp. in lower gears, but no SES light. My initial GUT feeling? (important) Bad MAFs. So I took the sage advice from this board and cleaned the MAFs with some CRC MAF cleaner, but I didn't see any improvement. I took it to BMW of Bellevue and had the foreman drive it. His suggestion? Bad tank of gas - run some Chevron + Techron through it. I was going to do that, but I started getting the SAME symptoms you had:

Rev Hunting
Lunging in 1st/2nd
A misfire or two
Trouble accelerating past 60 MPH or so (lag)

Finally got the SES light, so I nervously drove it into the BMW/Bellevue dealer. They ran diagnostics. The verdict? Bad MAFs. There were other codes showing up but they were MAF-related. Should have listened to my instincts. Luckily my aftermarket warranty covered both the diagnostics + MAF hardware. Good thing b/c they wanted $1200 for parts and labor.:eek:oohhh: My next order of business is to:

1) Order a spare set of MAFs.
2) Order a Peake reader.

Lesson learned?
Listen to the guys on this board, they know what they are talking about.
Same symptoms for me shortly after I bought mine but I did have the SES light on (and nobody muddied the water by telling me it was running lean).

Diagnosed as CPS faults, intake and exhaust, PLUS MAFs.

All changed, spare MAFs bought, different driving experience. It is a true beast now.

A Peake reader is your best investment before you start spending megabucks on a process of elimination.
 

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ok mafs could be the culpret did you unlock your cluster and do test number 4 and see what your mafs are going. also it sounds like you might have a vacume leak that can also be the culpret. start with your basics
 

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Discussion Starter · #8 ·
I have a peak reader... and the codes pulled are the only codes the car is throwing. Although I have heard a rumor that BMW stopped our cars from throwing a code for the MAF so they would not have to warrantee them. The tech I took the car too had some kind of LCD computer that he plugged in and I took it for a spin. Now... How do I "unlock your cluster and do test number 4 and see what your mafs are going"? I will go pick up some MAF cleaner and see if that makes a difference. Fuel filter does sound interesting.... could be the case since the car runs lean on idle.

I actually purchased this car in Seattle... came with a recommendation from M5Don. The car is in amazing condition and was owned by a BMW tech... although the car is in incredible mechanical condition... I knew something was up the first time I tried to drive it hard... just not very fast.

Aaron
 

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Discussion Starter · #9 ·
Another Washingtonian :blabla: My car had symptoms similar to yours, the short story:

Got my Beast about a month ago, at which point it felt really strong. About 2 weeks after I had it, I had a noticeable decrease in acceleration, esp. in lower gears, but no SES light. My initial GUT feeling? (important) Bad MAFs. So I took the sage advice from this board and cleaned the MAFs with some CRC MAF cleaner, but I didn't see any improvement. I took it to BMW of Bellevue and had the foreman drive it. His suggestion? Bad tank of gas - run some Chevron + Techron through it. I was going to do that, but I started getting the SAME symptoms you had:

Rev Hunting
Lunging in 1st/2nd
A misfire or two
Trouble accelerating past 60 MPH or so (lag)

Finally got the SES light, so I nervously drove it into the BMW/Bellevue dealer. They ran diagnostics. The verdict? Bad MAFs. There were other codes showing up but they were MAF-related. Should have listened to my instincts. Luckily my aftermarket warranty covered both the diagnostics + MAF hardware. Good thing b/c they wanted $1200 for parts and labor.:eek:oohhh: My next order of business is to:

1) Order a spare set of MAFs.
2) Order a Peake reader.

Lesson learned?
Listen to the guys on this board, they know what they are talking about.
So what is the diff between these VW and the BMW MAF's?
 

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MASSSSSSS AIR FLOW

You can't go wrong there!
 

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MAF's - 90% given .. so many posts about the limp mode.

My car feels sluggish and every so often in traffic or driving the engine "looses" power and runs rough for about a min just to re-gain the power and drive normally. I reset SES light couple days ago, today it lost power and SES light came on and then i regained power. I ordered new MAF's yesterday, will see how that goes.
I think YOUR problem, coming and going, might be a CPS starting to fail... MAFs usually go bad gradually and don't work some days and be down other times....

But you are all on the right path- the holy trinity MAFs, CPS, O2 sensors... maybe add plugs too

A
 

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Discussion Starter · #12 · (Edited)
MAF Test..

Alright... I just bought some CRC MAF cleaner and tested both of them out. On a scale of 1 to 10 i felt a .5 difference. I think my MAF are ok... now... what about the CPS? What is the best place to pick these up? How many are there on the car? The BMW tech who owned this car before me just put new plugs in it among other things... Im trying to eliminate some simple fixes before I take the car back to seattle to have a couple guys look at it... 02 sensors should be fine because Im not getting any SMS or codes for them... Still leaning towards fuel filter...


((a
 

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ok the fuel filter is a half hour job at best it will not hurt you in any way to change it. if you change it and it does not work who cares you just did some maint work instead no harm. also what i would do to eleminate vacume leak theroy is take a can of throttle body cleaner start the car up let it idle and spray around the plenum area see if you hear a diffrence in rpms at any point. remeber a slight vacume leak will give you a lean condition mafs are saying one thing and the o2 sensors are saying another and car freaks out :7:
 

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Discussion Starter · #14 · (Edited)
Vacume Leak...

The reason I dont think its a Vacume leak is that the car has odd hesitations when it is cold but then only acts odd under 2k or so when it is warm... and over 5k in 4th gear and 6k in 3rd gear.... Had a Vacume leak on my M3 and the problem existed while it was cold and warm...

((a
 

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The reason I dont think its a Vacume leak is that the car has odd hesitations when it is cold but then only acts odd under 2k or so when it is warm... and over 5k in 4th gear and 6k in 3rd gear.... Had a Vacume leak on my M3 and the problem existed while it was cold and warm...

((a
Given all that, change the fuel filter first. Easy enough. If you have the old plugs, have someone "read" them to see how lean you are and if in all cylinders.

Next are MAF's. Usually cleaning helps, not so in your case. Unlock OBC, go to test#4, second function which is liters per hour (L/H). Run the car to redline in second or third gear at WOT. Just before you hit the rev limiter, read the L/H. Should be in the 130 or better range. If off by a bunch (say 110), you need new MAF's.

BMW only sells the MAF with the housing, $$$$$. Get the virtually identical VW MAF, going for around $85-$90 each (you need two). It is a five minute job to swap out, even if you don't have a 5 pt security torx bit that some cars need (replace with phillips head screw, use vise grips to twist old ones out).

And just for grins, throw in a can or two of Techron or the German equivalent (can't remember name, comes in a blue bottle). That will help with deposits.

Report back and let us know how it went!!!:thumbsup:
Regards,
Jerry
 

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Discussion Starter · #16 ·
Given all that, change the fuel filter first. Easy enough. If you have the old plugs, have someone "read" them to see how lean you are and if in all cylinders.

Next are MAF's. Usually cleaning helps, not so in your case. Unlock OBC, go to test#4, second function which is liters per hour (L/H). Run the car to redline in second or third gear at WOT. Just before you hit the rev limiter, read the L/H. Should be in the 130 or better range. If off by a bunch (say 110), you need new MAF's.

BMW only sells the MAF with the housing, $$$$$. Get the virtually identical VW MAF, going for around $85-$90 each (you need two). It is a five minute job to swap out, even if you don't have a 5 pt security torx bit that some cars need (replace with phillips head screw, use vise grips to twist old ones out).

And just for grins, throw in a can or two of Techron or the German equivalent (can't remember name, comes in a blue bottle). That will help with deposits.

Report back and let us know how it went!!!:thumbsup:
Regards,
Jerry
Just went out and drove the car again... I must say I think im starting to feel something since i cleaned the MAF's... I took it out on the Freeway this time and could barley get it to go into Limp Mode in 3rd gear right before red line... I think im going to order those VW MAF's... got a link for em? Also going to replace the fuel filter to be safe.

((a
 

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Just went out and drove the car again... I must say I think im starting to feel something since i cleaned the MAF's... I took it out on the Freeway this time and could barley get it to go into Limp Mode in 3rd gear right before red line... I think im going to order those VW MAF's... got a link for em? Also going to replace the fuel filter to be safe.

((a

Do a search for VW MAFs don't have a link handy. (maybe someone else does).
Check Board sponsors too to see if any of them carry the VW MAF's.
Regards,
Jerry
 

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I started having the problems vafter cleaning my MAFs. It was loosing power when I first powered on the car after cleaning my MAFs, after a while the car started running well. A little later same problem happened.

Anyway, the MAFs are on FedEx truck down the street so I am just waiting for them to be put in!! Yaay

I think YOUR problem, coming and going, might be a CPS starting to fail... MAFs usually go bad gradually and don't work some days and be down other times....

But you are all on the right path- the holy trinity MAFs, CPS, O2 sensors... maybe add plugs too

A
 

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Discussion Starter · #19 · (Edited)
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