Engine cranks but doesnt start in cold

Tiny
JEETAN
  • MEMBER
  • 2003 HYUNDAI SONATA
  • 2.0L
  • 4 CYL
  • 2WD
  • MANUAL
  • 45,000 MILES
It does not start in cold conditions it just cranks, but once it is kept in hot sunlight for an hour it starts and no problems for the day.
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Monday, December 12th, 2016 AT 3:48 PM

8 Replies

Tiny
STEVE W.
  • EXPERT
These are always "fun" to track down. Basically what is happening is that the cold is causing a component/connection to shrink and fail. Once it has been warmed up the problem goes away. The issue is that it could be just about any part.
The issue could be on the fuel side or ignition.
First thing to do is narrow it down to one or the other. Rent/borrow a fuel pressure test set and run a pressure test.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

If it tests okay (which I think it will) then comes the hard part. Take a common hair drier, turn it to high and start heating the individual parts. Start with the crank sensor. Located on the front of the engine near the crank pulley. Heat it a bit then try to start the engine. Next the cam sensor (rear of cylinder head) I suspect you will not need to go farther than those two. However, if they do not help, apply heat inside at the bottom of the dash in the middle aimed at the PCM up behind the dash. If it starts then the PCM is the issue.

Good luck and report back. Thanks
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Tuesday, December 13th, 2016 AT 2:31 PM
Tiny
JEETAN
  • MEMBER
Sir, thanks for your efforts, the think is now if I am turn on off the keys for 7 to 8 times then if I start it starts, is there an issue with ignition coil.
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Wednesday, December 14th, 2016 AT 7:27 PM
Tiny
STEVE W.
  • EXPERT
The power being applied that way is causing the failing component to warm up enough to operate. That is why the testing for this type of problem costs so much, takes a bunch of time.
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Thursday, December 15th, 2016 AT 9:26 AM
Tiny
JEETAN
  • MEMBER
Sir I have changed the crank shat piston sensor, but the problem remains the same. What is crank sensor located in front of the pully. I coudnt check it then what I did is I removed the ecu and the ignition coils when it was cold, then I fixed it when it was hot car suddenly it started, what I think is ecu and iginition coils are good
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Tuesday, December 27th, 2016 AT 8:40 AM
Tiny
KEN
  • ADMIN
Hey JEETAN

When the engine doesn't not start do you have fuel pressure and spark at the plugs?

Please let us know what you find so it will help others.

Best, Ken
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Friday, December 30th, 2016 AT 5:07 PM
Tiny
JEETAN
  • MEMBER
Yes sir there is fuel pressure and spark at plugs
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Saturday, December 31st, 2016 AT 11:19 PM
Tiny
KEN
  • ADMIN
Let's check it see if you have injector pulse, here is a guide to help you see hoe to do it.

https://www.2carpros.com/articles/how-to-test-a-fuel-injector

Let me know.

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Monday, January 2nd, 2017 AT 10:56 AM
Tiny
STEVE W.
  • EXPERT
HMM, didn't see Jeetans reply but saw yours Ken. Anyway, I talked to a Hyundai tech about this, First thing he said was crank sensor.
I asked him why, He said it's a common issue on them, the sensor doesn't set close enough to the crank to generate a reliable signal. Then when the car is cold the battery tends to not crank it fast enough to signal the PCM. His fix was to remove the sensor, use a swab to clean out the hole and replace the sensor with a new one. Then load test the battery and/or clean the terminals and ground connections.

He also mentioned the main control relay can cause this.
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Monday, January 2nd, 2017 AT 1:22 PM

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