2.3 reasonable MAF sensor reading at idle? - Ranger-Forums - The Ultimate Ford Ranger Resource


SOHC - 2.3L & 2.5L Lima Engines Discussions and Topics specific to the Lima 4 cylinder engines

Reply
 
LinkBack Thread Tools Search this Thread
  #1  
Old 03-29-2016
Member
Thread Starter
 
Join Date: Mar 2016
Location: Gilroy, California
Posts: 60
Icon5 2.3 reasonable MAF sensor reading at idle?

I'm chasing a PO171 problem and have a scan tool. According to some information I've read, the idle MAF number in grams of air should be about the same as the engine size, i.e. 2.3 grams/sec for my 2.3.

I've graphed the MAF with my scan tool, and at idle it runs about 3.7. + or - about .2. This seems excessive and makes me think it could be the source of the PO171. Can someone with a scan tool (or knowledge) advise?

I've installed a new air cleaner, cleaned the MAF sensor with the CRC stuff, and assured that all hoses are connected and clamps tight. I also cleaned the MAF sensor electrical connection and put a dab of dielectric grease inside.

Thanks for looking.
Reply With Quote
  #2  
Old 03-29-2016
RF Veteran
iTrader: (1)
 
Join Date: Jan 2014
Location: Vancouver, BC
Posts: 7,585
Yes, the displacement and gm/sec should be about the same, but that is also assuming 650-700 rpm idle, so warmed up engine.
Higher RPMs would, of course, mean higher air flow.

Cold engines often idle above 1,000

The 2.3l, like many 4cyl engines, often idle at 800, or higher on automatics, even after warm up.

And a false higher air flow would cause P0172(rich) not P0171(lean)

For example:
Computer would add enough fuel for 3.7 gm/sec, if this was a false high reading and air flow was really 2.7 gm/sec then computer is adding too much fuel.
When air/fuel mix is burned O2 sensor would report less oxygen(rich), so computer would reduce the amount of fuel it is adding, "-" fuel trim numbers, like -10 STFT
If it gets to -20 STFT then computer will set P0172(rich) and turn on the CEL

Lean code is when less air is reported by MAF sensor, usually because of a vacuum leak, not all the air coming into engine is coming thru the MAF sensor.
So at idle you might see, 1.5-2 gm/sec, when it should be 2.7 gm/sec, so computer is adding less fuel than it should, after it is burned O2 shows too much oxygen so computer adds more fuel, "+" fuel trims, when +20 STFT is seen then computer sets P0171 code, Lean
Reply With Quote
  #3  
Old 03-29-2016
Member
Thread Starter
 
Join Date: Mar 2016
Location: Gilroy, California
Posts: 60
Icon5

Thanks yet again, Ron. Would you like to visit Gilroy and stay in my spare bedroom for a couple of weeks?
Reply With Quote
  #4  
Old 03-29-2016
RF Veteran
iTrader: (1)
 
Join Date: Jan 2014
Location: Vancouver, BC
Posts: 7,585
Is that Old Gilroy or Gilroy, lol.

I grew up in southern cal, driven up 101 more than a few times, I remember the road from Salinas over to Gilroy as very beautiful, probably a 6 lane freeway by now
Reply With Quote
  #5  
Old 03-29-2016
Member
Thread Starter
 
Join Date: Mar 2016
Location: Gilroy, California
Posts: 60
Icon14

Quote:
Originally Posted by RonD View Post
Is that Old Gilroy or Gilroy, lol.

I grew up in southern cal, driven up 101 more than a few times, I remember the road from Salinas over to Gilroy as very beautiful, probably a 6 lane freeway by now
It IS 6 lanes now (old 101 bypassed Gilroy in 1985) but it's still beautiful, and still smells like garlic. :-)
Reply With Quote
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
2007 Ford Ranger for $12,500 or Reasonable Best Offer located in USA - Maine. FordTough2007 Ranger Based Vehicles 12 04-04-2015 04:09 PM
MAF Sensor - Upgraded Intake and rough idle for 10 seconds on start patkelly1336 4.0L OHV & SOHC V6 Tech 14 04-10-2012 01:28 PM
A/C Broken - $690 to repair reasonable? Marcaronio 2.9L & 3.0L V6 Tech 10 07-04-2008 06:40 PM
Reasonable price for this stuff??? Needforspeed3685 General Ford Ranger Discussion 0 03-11-2008 03:55 PM
Reasonable question osr1 2.9L & 3.0L V6 Tech 1 02-20-2008 10:49 PM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -6. The time now is 08:54 PM.


We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.