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MAF wiring diagram needed?

Tiny
EARL91
  • MEMBER
  • 2014 CHEVROLET CAPTIVA
  • 2.4L
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 160,000 MILES
Random or multiple misfires. Checked the coils and plugs, nothing there. Unplugged MAF sensor and no change in idle. So, I need help with a wiring diagram for the MAF sensor so I can test it and see if it is bad or not. I attempted one just don't know if I got the wiring right for the test while running. Please and thank you.
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Wednesday, September 13th, 2023 AT 1:40 PM

3 Replies

Tiny
BORIS K
  • MECHANIC
  • 799 POSTS
Hello,

To my knowledge I have not seen a MAF issue cause random or multiple misfire codes.
Codes like this are usually caused by bad ignition coils, spark plugs, bad injectors, compression and possible intake air leaks. Bad wiring/connectors can also cause misfires.

When unplugging the MAF sensor the engine control module will replace the missing air mass signal with a factory pre-set replacement value.

Below are some diagnostic guides:

https://www.2carpros.com/articles/automotive-engine-misfire-code-p0300-causes-and-solutions
and
https://www.2carpros.com/articles/symptoms-of-engine-misfires-a-step-by-step-guide

A video:
https://youtu.be/e3YCZa2Ygpo?si=cIckU3jHiGY6xjJT

MAF sensor:
https://www.2carpros.com/articles/how-a-mass-air-flow-sensor-works-maf

Cheers, Boris
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Thursday, September 14th, 2023 AT 8:24 AM
Tiny
EARL91
  • MEMBER
  • 89 POSTS
When I open the oil cap it just blows air and oil back at me and smokes a lot. So, I believe there is either a stuck ring or worn valve stim or a seal somewhere. So I believe this engine is just done.
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Thursday, September 14th, 2023 AT 11:05 AM
Tiny
BORIS K
  • MECHANIC
  • 799 POSTS
Hello,

It sounds like your 2.4 Ecotec engine is suffering from the well-known clogged PCV system issue. The PCV, Positive Crankcase case Ventilation, system is prone to clogging and can cause high crankcase pressures.

It is a 2-part system, pipe to the left of the air intake to the valve cover and the main ventilation valve in the intake manifold.
To clean the intake PCV valve ideally remove the intake manifold, but it can be cleaned in situ too. See image 1
The other part, pipe to valve cover, is easily accessed by disconnecting from air intake and valve cover. Ideally remove valve cover to clean. See image 2.

A few videos:
https://youtu.be/a5gL_OMtFVc?si=bs2lCCnA_a_Xqlen
and
https://youtu.be/1uGTEWWrlSs
and
https://youtu.be/cyoJ02cAQig?si=g305lI4D_8t7FxjR
and
https://youtu.be/eRW5PCgwyhk?si=F7yyUa6cUTe-u0nJ

GM service bulletin:
https://static.nhtsa.gov/odi/tsbs/2015/SB-10057696-3071.pdf

Cheers, Boris
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Saturday, September 16th, 2023 AT 1:29 AM

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