Car switching off and wont idle

Tiny
SHAKEEL
  • MEMBER
  • 2009 HYUNDAI I20
  • 100,000 MILES
Car burning rich with fuel and causing spark plugs to turn black. Also, the car wont hold an idle and continuously switches off when slowing down, but when in motion runs normal. What could be the cause of this?
Friday, October 21st, 2016 AT 1:34 PM

6 Replies

Tiny
JIS001
  • MECHANIC
  • 3,411 POSTS
Check your mass air flow sensor. With a scanner that can read live data, look at mass air flow sensor reading. Should read grams per second. So if your engine is a 2.0L you should see something close to 2g/s on your reading. Tap sensor and see if readings change too much or drop out close to 0. If it does replace the Mass Air Flow sensor.
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Friday, October 21st, 2016 AT 2:43 PM
Tiny
JIS001
  • MECHANIC
  • 3,411 POSTS
Forgot to mention, that reading is while vehicle idles and no loads on.
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Friday, October 21st, 2016 AT 2:44 PM
Tiny
AL514
  • MECHANIC
  • 4,692 POSTS
Just to add, is the check engine light on?
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Friday, October 21st, 2016 AT 4:50 PM
Tiny
SHAKEEL
  • MEMBER
  • 3 POSTS
No engine light on. The car has normal readings just not holding idle and keeps switching off when slowing down. Mechanic is saying head gasket then others says manifold intake gasket others saying o2 sensor, but what you are saying makes sense as it does sound like it is sucking in air and revs are under 1000 rpm's so it struggles to keep idling.
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Saturday, October 22nd, 2016 AT 3:52 AM
Tiny
SHAKEEL
  • MEMBER
  • 3 POSTS
Just to add, when mechanic plugged in machine he got an error p0108 map sensor.
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Saturday, October 22nd, 2016 AT 3:55 AM
Tiny
JIS001
  • MECHANIC
  • 3,411 POSTS
Check your map sensor signal voltage. At sea level you should see around 1 volt.
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Saturday, October 22nd, 2016 AT 9:31 AM

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