No 12 Volt supply to coil pack for numbers two and three

Tiny
YESHIN_F
  • MEMBER
  • 1995 HYUNDAI ACCENT
  • 1.3L
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 200,000 MILES
Please Help. There's no 12 volt supply to coil pack for #2 #3, only coil for #1 #4 have 12 volt supply from ECU. Car in running condition but low power because only #1 and #4 spark plug are working. We have replaced new coil pack and camshaft sensor still no 12 volts supply to coil #2 #3. Thank you
Saturday, November 21st, 2020 AT 9:57 AM

5 Replies

Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
Good afternoon,

This could be either the coil assembly itself or wiring and the ECM.

I attached a wiring diagram for you to view.

The 2 wires at the ECM that I circled are grounds for the coil to fire the spark plugs. You need to test for voltage at those 2 wires with the key on.

https://www.2carpros.com/articles/how-to-check-wiring

Roy
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Saturday, November 21st, 2020 AT 12:00 PM
Tiny
YESHIN_F
  • MEMBER
  • 5 POSTS
Good day Sir Roy. Thank you for you reply. Probably it's not the coil sir because it's new and have it checked and it's good. We've checked the voltage from the ECU and read brown/red (coil#1 #4)= 12 volts, and blue/yellow (coil#2, #3)= only less than 2 volts. We also found out that the original 3 wire crankshaft sensor has no ground itself and still the other two wires produce both 5 volts. Does it have something to affect? What shall we do next Sir? Thank you in advance.
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Sunday, November 22nd, 2020 AT 2:01 AM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
Okay, the blue/yellow wire should have 12 volts as well. You have power from the red wire which powers the coil. The 3 wires to the ECM are grounds for the coils, not powers.

Since you have no power to that wire, it means either you have a bad new coil assembly or the wire from the ECM to coil is open.

https://www.2carpros.com/articles/how-to-check-wiring

No to the crank sensor. If that was the issue. it would not run at all.

https://www.2carpros.com/articles/how-a-crank-shaft-angle-sensor-works

https://www.2carpros.com/articles/symptoms-of-a-bad-crankshaft-sensor

Roy
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Sunday, November 22nd, 2020 AT 4:43 AM
Tiny
YESHIN_F
  • MEMBER
  • 5 POSTS
Good day Sir Roy,

We have cleaned the contact pins of the coil pack. We now have 12 volt supply From the 3 wire coil pack both blue/yellow and brown/red to ECU and the 12 volt for black/white from ignition to coil pack, but still no power from the coil pack (#2, #3) to spark plug. Please advice us what to do next. Thank you so much.
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Sunday, November 22nd, 2020 AT 9:43 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
If you have power from the coil to the ECM on both wires for coil 2 and 3, then you need an ECM.

Roy
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Monday, November 23rd, 2020 AT 3:28 AM

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