2004 Kia Sorento Won't start. Backfires through intake.

Tiny
SAMSONROACH
  • MEMBER
  • 2004 KIA SORENTO
  • 134,000 MILES
Problem started by not starting one afternoon without considerable coercing. Several minutes and several pedal stomps it started as if it were a cold untuned carbureted engine. Replaced spark plugs. Continued to have trouble starting but could be talked into starting. After a week of this, it progressed in to a shut down while driving. It's a manual, but popping the clutch while coasting would not restart. Heard loud popping when trying to start. Could smell lots of fuel out exhaust. Removed breather up to throttle body and tried to start which is when I noticed that the popping was a backfire through the intake as evidenced by fireballs in my face. CEL came on one week before all this started but both places said it was an O2 sensor. Sometimes it will start and run for 5-15 minutes with no trouble and plenty of power, but when it shuts down its out for the count.
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Tuesday, July 30th, 2013 AT 5:22 PM

3 Replies

Tiny
JACOBANDNICKOLAS
  • EXPERT
You need to check two things for me. First, when it won't start, check to see if the fuel pressure is within the manufacturer's specs at the fuel rail. Also, check to see if you are getting spark to the plugs.

Let me know what you find.
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Tuesday, July 30th, 2013 AT 7:23 PM
Tiny
SAMSONROACH
  • MEMBER
There is no Schrader valve on the fuel rail so I cannot check the fuel rail without dismantling the intake manifold. I can separate the fuel lines at the firewall but that would only give me fuel pump pressure and the engine still will not start even with starting fluid. The driver side has three ignition coils that piggyback over to the passenger side bank. I am only able to get one plug wire off the passenger side front cylinder. I put a screw in it and held it off the valve cover and did not get a spark. Is there a better way to prove spark on this type of engine and set up? It feels as if there is an on/off switch on this engine and it's stuck in the off position despite everything else. Is there anyway to be certain that I don't have a short or an ignition switch problem?
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Wednesday, July 31st, 2013 AT 10:03 AM
Tiny
JACOBANDNICKOLAS
  • EXPERT
If it won't start with starting fluid, then it is my belief that there is no spark as you mentioned. Now, you need to check to see if there is power to the coil.
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Thursday, August 8th, 2013 AT 6:26 PM

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