Car's running lean, rough idle sometimes but no code

hun77777 · 05-24-2009, 03:54 AM

my HPFP has been replaced under its open campaign last year even before i asked for it and it's been about a year now. car starts up just fine and there's no apparant symptoms like what many of you guys are saying, except time to time there's rough idle (rpm goes up to 800 from its normal 600) with very slight miss-fires. it was worse before i replace spark plugs but it seems better afterwards...

anyways, just dyno'd my car last week and it's running lean all the way through... and that got me worried and thinking it perhaps is hpfp since running lean = not enough fuel... i don't know if i'm just worrying bit too much... perhaps it's map, perhaps it's some other things... just trying to see what you gurus are thinking...

TheTwinz · 05-24-2009, 04:27 AM

I think long cranks is one of the main symptoms of HPFP failure.. that and rough idles... So, not to rule out HPFP, but I dont think that is your main problem right now.

hun77777 · 05-24-2009, 05:30 AM

i don't have long cranks, as many people are experiencing. i just thought hpfp might be one of the reason why my car is running lean. but then again there could be tons other factors that can make the car run lean so...

SoCali E36 · 05-24-2009, 06:03 AM

Quote:

Originally Posted by TheTwinz

I think long cranks is one of the main symptoms of HPFP failure.. that and rough idles... So, not to rule out HPFP, but I dont think that is your main problem right now.

wow my car does this everyday. i took it in to the deal but they say its working fine. what can i do?

seccsc · 05-24-2009, 09:51 AM

It could be bad gas, especially if it has an ethanol supplement. Ethanol has a high probability of absorption of H2O(most areas of country have had increased levels of rain). That's just my .02 cents.....

kptaylor · 05-24-2009, 12:59 PM

Don't take a dyno A/F ratio for gospel, either. Too many variables on the sniffer to make it reliable.

05-24-2009, 03:54 AM	#1
hun77777 Brigadier General 199 Rep 4,646 Posts Drives: SG E92 Join Date: Nov 2007 Location: Seattle WA iTrader: (58)	Car's running lean, rough idle sometimes but no code - can this be HPFP problem? my HPFP has been replaced under its open campaign last year even before i asked for it and it's been about a year now. car starts up just fine and there's no apparant symptoms like what many of you guys are saying, except time to time there's rough idle (rpm goes up to 800 from its normal 600) with very slight miss-fires. it was worse before i replace spark plugs but it seems better afterwards... anyways, just dyno'd my car last week and it's running lean all the way through... and that got me worried and thinking it perhaps is hpfp since running lean = not enough fuel... i don't know if i'm just worrying bit too much... perhaps it's map, perhaps it's some other things... just trying to see what you gurus are thinking... __________________ SGE92TT......................... 12.331 Sec @ 117.89 Mph............................POWERED BY l BMS DCI l HELIX IC l FORGE DVs l RR OCC & CP & SCOOPS l AR 3" DPs l AE QUADs l BLISTEIN PSS10 l P3 VENT GUAGE l VISHNU PROCEDE V5 AUTOTUNE l Lots of Window Stickers
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05-24-2009, 04:27 AM	#2
TheTwinz Second Lieutenant 14 Rep 273 Posts Drives: 300Z Join Date: Feb 2009 Location: 911 iTrader: (0)	I think long cranks is one of the main symptoms of HPFP failure.. that and rough idles... So, not to rule out HPFP, but I dont think that is your main problem right now.
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05-24-2009, 05:30 AM	#3
hun77777 Brigadier General 199 Rep 4,646 Posts Drives: SG E92 Join Date: Nov 2007 Location: Seattle WA iTrader: (58)	i don't have long cranks, as many people are experiencing. i just thought hpfp might be one of the reason why my car is running lean. but then again there could be tons other factors that can make the car run lean so... __________________ SGE92TT......................... 12.331 Sec @ 117.89 Mph............................POWERED BY l BMS DCI l HELIX IC l FORGE DVs l RR OCC & CP & SCOOPS l AR 3" DPs l AE QUADs l BLISTEIN PSS10 l P3 VENT GUAGE l VISHNU PROCEDE V5 AUTOTUNE l Lots of Window Stickers
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05-24-2009, 09:51 AM	#5
seccsc Captain 244 Rep 719 Posts Drives: G20 M340xi Join Date: Jun 2006 Location: VA iTrader: (0)	It could be bad gas, especially if it has an ethanol supplement. Ethanol has a high probability of absorption of H2O(most areas of country have had increased levels of rain). That's just my .02 cents..... __________________
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05-24-2009, 12:59 PM	#6
kptaylor First Lieutenant 6 Rep 322 Posts Drives: '07 335i Coupe Join Date: Mar 2007 Location: PHX, AZ iTrader: (0)	Don't take a dyno A/F ratio for gospel, either. Too many variables on the sniffer to make it reliable.
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