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2001 blazer 4wd Ls

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  #21  
Old 05-19-2018, 09:06 AM
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Originally Posted by Davewho
I pulled hose off idle went up I plugged it idle went back to where it normally is (but still to high to pass smog) does that mean no vacuum leak ?? Hey I appreciate the heck out of ya for the learnin I'm getting from ya
Once again Block the flow in a vacuum hose that goes to a manifold, not pull off. If you block it then You surely have no leaks through a vacuum hoses, right? If that helps it means You had a leak into the hoses, if it does not - it means vacuum lines are ok.
 
  #22  
Old 05-19-2018, 09:12 AM
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Originally Posted by GeorgeLG
If it is an air leak and if it is a vacuum leak in particular, your fuel trims will be more positive at idle and less positive at 2500 rpm when the vacuum leak is a smaller percentage of the total air.
Plus, if the air leak is significant, the idle RPMs are going to increase or even surge on starting.
 
  #23  
Old 05-19-2018, 09:36 AM
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Shrtft1 1.6 shrtft2 2.3. LONGFT1- 9.4 LONGFT2 9.4 at idle (940) at 2500rpm shrtft1 -0.8 . shrt2 0.0. LONGFT1- 7.0 LONGFT2 7.0 thank you for your time and in put I hope this is what you askef
 
  #24  
Old 05-19-2018, 10:11 AM
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Do you have the short term fuel trims that go with the numbers in your first post?

George
 
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Old 05-19-2018, 10:17 AM
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Shrtft1 0.0 shrtft2 2.3 thank God I took pictures of all that
 
  #26  
Old 05-19-2018, 10:20 AM
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MAF(lb/s). 0.02. Does that mean anything bad?
 
  #27  
Old 05-19-2018, 11:30 AM
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Our MAFs are measured in grams per second. There's probably a conversion you can use. I never have. What is the IAC counts (or %) and the TPS angle at idle?
 
  #28  
Old 05-19-2018, 11:41 AM
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MAF readings are usually stated in grams per second. At idle, that number should be around the displacement of the engine or 4.6 g/s ish. The stated amount in pounds per second is too coarse for a useable conversion. This is only a general rule of thumb and more diagnosis is required to properly assess the MAF sensor function.

Your fuel trims (LTFT+STFT on a given bank) have changed dramatically. Have you changed anything on the truck to account for this? Also please restate all 4 fuel trims from both measurements with plus and minus signs on every number. I cant tell if the "-" marks are punctuation or negative numbers and if the lack of a sign means positive numbers.

George
 

Last edited by GeorgeLG; 05-19-2018 at 11:49 AM.
  #29  
Old 05-19-2018, 01:35 PM
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As far as drastic change in the fuel trim numbers I cleaned TB changed all vacuum lines as far as new # shrtft1 -0.8 LONGFT1 +11.7. shrtft1 +1.6. LONGFT2. +13.2 I changed to metric on scanner and got MAF 8.6 g/s rite at 890rpm
 
  #30  
Old 05-19-2018, 01:39 PM
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I'm using a cen-tec 60794 obd11- +abs and I can't find anything on there about AIC but the TPS is 0 % at idle
 


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