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Discussion Starter #1
Hey guys,


well the other day I was driving my m5 and realized once I got past about 4k rpms or under heavy acceleration my car seemed to sputter out and slowly creep up in rpms even though I was flooring it. I also would have a hiccup here and there in the lower rpms. the problem has gotten worse the last two days going to lower rpms and on start up its had a rough idle until finally she wont even start up.


I pulled the following codes from the car:


p0175 running rich bank 1
p0491 secondary air system bank 1
p0441 evaporative emission fail purge flow
p0172 running rich bank 2


I was thinking I might need a new fuel pump because its sounded like I have a supercharger in the back seat for a while now and this seems to be a fuel problem. Also I have replaced mafs recently and o2s within the last 500 miles and I have already tried unplugging the mafs and it had no effect on the problem.
:crying
 

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Post doesn't need the DIY label...


How many miles on the car? Any record of fuel pump and filter being changed? CPS's ever been changed?

Could be fuel pump and filter issue, but my experience with a failed fuel pump is that it was working fine one minute, the next minute the car was dead.

Common suggestion will be to clear the codes and see what comes back after driving a bit.
 

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01 Carbon/Silverstone Exhaust: Jedders-HJS high flow cats-resonator delete-Xpipe-Eisenman cans
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The symptoms sure sound like a failing fuel pump. The SA and EVAP codes are unrelated. The rich codes are odd if the pump is failing but maybe they are old codes from before you changed your MAFS and O2S.

You need to test your pump look in the DIY fuel section.
 

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Discussion Starter #4
Thanks for the replys,

I changed the fuel filter at about 142000 miles and the car now has 151000 on it.
The car started up this morning like nothing was even wrong but the ses came on so I'll try and check the codes later today and see what I get.
 

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01 Carbon/Silverstone Exhaust: Jedders-HJS high flow cats-resonator delete-Xpipe-Eisenman cans
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Fuel pumps don't all crump the same way. Some are sudden instant death and some circle the drain for while first. As bcampbe said write down your codes then clear them to see which ones are active.
 

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Fuel pumps don't all crump the same way. Some are sudden instant death and some circle the drain for while first. As bcampbe said write down your codes then clear them to see which ones are active.
Often, heat will affect a fuel pump on the way out. Good when cold (first start of the day), as it heats up, it loses its ability to perform. Testing the fuel pump "relay" may be helpful; if almost too hot to touch, fuel pump is drawing too much current and I would guess on its last legs. Interested in codes read after old ones cleared.

Regards,
Jerry
 
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Discussion Starter #8
Hey guys so I just rented a obd because the car won't stay on for more than a few seconds and i pulled the same codes after I cleared them. The evap codes have been on the car for awhile but the running rich codes are new. These are confusing me because the car acts just like it's not getting any gas.
 

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Check your TB vacuum lines too. You may have a couple of items that need attention.
 

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I wouldn't trust those P0172/P0175 codes on these cars. There has been discussion in the past on here and other BMW forums about if they really should be lean codes as people have cleared them by fixing air leaks, which cause lean running. I think the conversion to some P codes within the BMW software is dodgy.

Lean codes would support a dying fuel pump which is certainly what it sounds like.

Try a simple test. Turn the ignition on, with your seat belt on. Wait for all the beeps and dings to stop so it's nice and quiet. And then turn the key to the crank position WITHOUT depressing the clutch. You should hear the pump start and run smoothly for a few seconds and then stop. If it doesn't run, or runs at an irregular speed, you need a new one. Do the test a few times

Malcolm.
 
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