Well I'm about over this BMW habit of P0171 and 0174 codes. :banghead:
I have a 2005 330 Ci with 142K on the odometer. Some of you will remember my thread from last summer [URL="//http://ift.tt/1jkOjKM"]on the same subject but I firmly believe this is a different problem. About two months ago I started to notice my MPG gauge, which is a indicator of manifold vacuum, was bottoming out very early on acceleration, as in before i got to 2000 rpm. within a week of noticing it, i got the p0174 and 0171 codes. So I cleared the codes and began monitoring the Fuel trims, both short and long term, and found that the short terms were about +4 or so at idle and the long terms were in the 12 to 13 range. I thought ok i have another vacuum leak and need to find it. Now fast forward a month, I have replaced VCG, CCV, all CCV hoses, all small rubber vacuum hoses, all 6 CCV manifold orings, Intake gaskets, DISA oring, Dipstick orings (all three), ICV boot, Throttle Body gasket, Fuel regulator hose, all the rubber nipple plugs i can find. The intake boots are less than a year old and are still in great shape. Smoke test shows nothing.
Now at idle my short term trims are +/- 2 but the long term trims wont get below 8. If I drive highway time the trims go up above 10 again but around town they stay below the CEL cutoff of ten.
I saw a post by JFOJ about opening the oil fill while monitoring the STFTs and watching for the numbers to jump 20% then return quickly when the oil cap is replaced. Mine jumped to 27% immediately and returned within 10-15 seconds to zero when i replace the cap. His theory is this would indicate a sealed Crankcase and if that's true then mine should be fine.
My vacuum numbers according to the Torque App are 19.6 at idle and as i said it goes to boost (positive manifold pressure)at around 2000 rpm under a mild load.
I am about convinced that my MAF is under reporting, but I would like to hear from you guys and gals if you can think of anything I'm missing. The MAF reports 3.5 G/sec at idle and about 145 G/sec at 6000. I ran the flow numbers through a VE calculator and it consistently comes up with 80% Volumetric Eff. which would indicate that the MAF is close at higher RPMs but I can't think of what else to try.
Would a MAF problem cause the manifold vacuum to do what I have described.
I know I've thrown a lot out there but any input would be appreciated just please dont tell me to go read JFOJs thread on P0171 and 0174 codes. I have it nearly memorized. :facepalm:
I would even contribute to someones MOD fund for a resolution to this issue.
Thanks in advance,
05
I have a 2005 330 Ci with 142K on the odometer. Some of you will remember my thread from last summer [URL="//http://ift.tt/1jkOjKM"]on the same subject but I firmly believe this is a different problem. About two months ago I started to notice my MPG gauge, which is a indicator of manifold vacuum, was bottoming out very early on acceleration, as in before i got to 2000 rpm. within a week of noticing it, i got the p0174 and 0171 codes. So I cleared the codes and began monitoring the Fuel trims, both short and long term, and found that the short terms were about +4 or so at idle and the long terms were in the 12 to 13 range. I thought ok i have another vacuum leak and need to find it. Now fast forward a month, I have replaced VCG, CCV, all CCV hoses, all small rubber vacuum hoses, all 6 CCV manifold orings, Intake gaskets, DISA oring, Dipstick orings (all three), ICV boot, Throttle Body gasket, Fuel regulator hose, all the rubber nipple plugs i can find. The intake boots are less than a year old and are still in great shape. Smoke test shows nothing.
Now at idle my short term trims are +/- 2 but the long term trims wont get below 8. If I drive highway time the trims go up above 10 again but around town they stay below the CEL cutoff of ten.
I saw a post by JFOJ about opening the oil fill while monitoring the STFTs and watching for the numbers to jump 20% then return quickly when the oil cap is replaced. Mine jumped to 27% immediately and returned within 10-15 seconds to zero when i replace the cap. His theory is this would indicate a sealed Crankcase and if that's true then mine should be fine.
My vacuum numbers according to the Torque App are 19.6 at idle and as i said it goes to boost (positive manifold pressure)at around 2000 rpm under a mild load.
I am about convinced that my MAF is under reporting, but I would like to hear from you guys and gals if you can think of anything I'm missing. The MAF reports 3.5 G/sec at idle and about 145 G/sec at 6000. I ran the flow numbers through a VE calculator and it consistently comes up with 80% Volumetric Eff. which would indicate that the MAF is close at higher RPMs but I can't think of what else to try.
Would a MAF problem cause the manifold vacuum to do what I have described.
I know I've thrown a lot out there but any input would be appreciated just please dont tell me to go read JFOJs thread on P0171 and 0174 codes. I have it nearly memorized. :facepalm:
I would even contribute to someones MOD fund for a resolution to this issue.
Thanks in advance,
05
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