LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

Split BLMs and car wont idle right...

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Old Apr 9, 2004 | 05:22 PM
  #1  
xxsaint69x's Avatar
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From: Peachtree City, GA
Split BLMs and car wont idle right...

what can be causing Left side to bottom out at 108 ? right is at 140ish. Also when i come to the stop the idle drops down to 400 before going back up. Drives me nutts.
Old Apr 9, 2004 | 05:59 PM
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Hows your fuel pressure.....I had some wierd stuff like that going on when my fuel regulator crapped out.
Old Apr 9, 2004 | 06:00 PM
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Originally posted by gb95zconv
Hows your fuel pressure.....I had some wierd stuff like that going on when my fuel regulator crapped out.

fuel pressure is set at 48psi...i have a AFPR
Marcin
Old Apr 9, 2004 | 06:16 PM
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I would back the fuel pressure down to 42 and see if your left BLM at least gets off the bottom limit where the pcm can control the fuel.

I would also check for a exhaust leak on the left.....false lean can cause fuel to be dumped resulting in a rich condition oddly enough.

Last edited by gb95zconv; Apr 9, 2004 at 06:23 PM.
Old Apr 9, 2004 | 09:15 PM
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no exhaust leaks as far as i can tell
Old Apr 9, 2004 | 09:29 PM
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hmmm....what can be causing my IAC values to be at 70 at idle (875 rpm) ? SHouldnt it be at around 30ish?
Old Apr 10, 2004 | 06:14 AM
  #7  
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ttt
Old Apr 10, 2004 | 11:30 AM
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fiured out the split blms one of the o2s in on the way out. I am guessing that will also fix the idle
Marcin
Old Apr 10, 2004 | 01:12 PM
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lets hope, let us know ifthat takes care of it. also, have you checked for vacuum leaks? if there's a vac. leak, the pcm will add fuel which will also make the iac counts shoot up and take out the 02s w/it. def. worth a check.
Old Apr 11, 2004 | 01:52 AM
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Originally posted by xxsaint69x
fiured out the split blms one of the o2s in on the way out. I am guessing that will also fix the idle
Marcin
yup, thats exactly what was happening on mine. I had just replaced the drivers O2 a few days before, then I noticed my BLM's were split, each maxxed in opposite directions. Slight idle and hesitation prolblem. New passenger O2 solved both problems immediately.
Old Apr 11, 2004 | 09:20 AM
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Originally posted by 92LT1RS
yup, thats exactly what was happening on mine. I had just replaced the drivers O2 a few days before, then I noticed my BLM's were split, each maxxed in opposite directions. Slight idle and hesitation prolblem. New passenger O2 solved both problems immediately.
before that the 02's seemed to be reading and switching properly? seems like I should probably replace mine since they are at least 5 years old. who knows, maybe orig..
Old Apr 11, 2004 | 09:43 AM
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the way i traced it to the o2s is i swaped the o2s, when i did that my split blms swaped sides as well
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