Crank, no start, spark?

Tiny
BOREWASH
  • MEMBER
  • 2003 HYUNDAI TIBURON
  • 2.0L
  • 4 CYL
  • 2WD
  • MANUAL
  • 105,000 MILES
Hi, I am having trouble with crank no start. Not getting spark at coil. Injectors not pulsing, coil not pulsing (tested with Noid light). Crank and cam sensors swapped for known working ones. Coil swapped for known working one. Everything is getting 12v or 5v. No engine codes, however, I am able to communicate with ECU. Fuses all checked. Battery good / starter good. Fuel pump primes. The timing belt is fine. The car was sitting for 2 weeks and previously had some rough idle and engine hunting. MAP/TPS changed and tried with them unplugged. It’s a Hyundai Coupe 2003. 2.0l. Can’t see any damaged wires and multimeter is giving normal readings on sensors. Any help would be appreciated!
Friday, October 25th, 2024 AT 11:07 AM

13 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 50,363 POSTS
Yep, it sounds like you have a shorted fuel injector which can cancel the signal from the PCM to the injectors. I would disconnect all injectors and test the OHM, s across each one which should be about 12 to 16 Ohm's.

Here is a guide to help:

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

Please go over this guide and get back to us.
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Friday, October 25th, 2024 AT 5:16 PM
Tiny
BOREWASH
  • MEMBER
  • 8 POSTS
I’m getting 15 ohms on all 4 injectors.
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Saturday, October 26th, 2024 AT 1:08 AM
Tiny
KEN L
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Okay they seem fine. When you say "I am able to communicate with ECU" do you mean you can't connect to the PCM? You may have a bad PCM.
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Saturday, October 26th, 2024 AT 9:38 AM
Tiny
BOREWASH
  • MEMBER
  • 8 POSTS
No, I mean I CAN communicate. So obd2 scanner connects, I can read data. No codes.
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Saturday, October 26th, 2024 AT 3:36 PM
Tiny
KEN L
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Gotcha, the scanner connected but no data and no codes. It sounds like the PCM is dead, but let's swap out the PCM power relay, check the ground for the PCM which is right above the brake pedal (G19). Also, we need to check fuse # 16 and 17 in the fuse panel inside the car. Here are two guides that will help and if none of these help I would get a preprogrammed unit by searching Google or Ebay. Here is the PCM and engine wiring diagrams so you can see how the system works, and I marked the grounds, relay and fuses to be checked.

https://www.2carpros.com/articles/how-to-check-a-car-fuse

and

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

Here is the location of the relay and fuses as well as how to change out the PCM. Check out the images (below). Please let us know what happens.

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Sunday, October 27th, 2024 AT 11:34 AM
Tiny
BOREWASH
  • MEMBER
  • 8 POSTS
Okay, you are misunderstanding me. My “PCM” is working, I CAN connect to it with an obd2 tool. I CAN read live data. NO codes are stored. I’ll look for that ground though thanks.

My car cranks but won’t start.
Fuel pump primes, however I've just tested, and it switches off during cranking. Injectors don’t pulse, ignition coil doesn’t pulse.

Immobilizer? No blinking light though.
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Monday, October 28th, 2024 AT 7:30 AM
Tiny
KEN L
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Okay, with the scan tool connected can you read live data of the engine speed while cranking?
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Monday, October 28th, 2024 AT 10:23 AM
Tiny
BOREWASH
  • MEMBER
  • 8 POSTS
Yes, it reads 0 RPM.
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Monday, October 28th, 2024 AT 12:36 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
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You found the problem, if the PCM does not see engine RPM it will not trigger coils or injectors, I would swap out the crankshaft sensor because it sounds like you have defective one. Here is the location so we can be on the same page. Check out the images (below). Let us know how it goes.
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Tuesday, October 29th, 2024 AT 10:36 AM
Tiny
BOREWASH
  • MEMBER
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Sadly the problem is more complicated then that. If you read my original post, I’ve already mentioned swapping out crankshaft sensor? Why are you telling me where it is? I know where it is, I’ve tried it in a replica model, it starts the car.

Surely the immobiliser can be causing this? Or a faulty fuel pressure regulator causing the ecu not to send signal?

Faulty wiring? All sorts
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Tuesday, October 29th, 2024 AT 11:50 AM
Tiny
KEN L
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Correct, I know you replaced the crankshaft sensor, but the only thing left is the PCM so I wanted to make sure before doing the computer replacement. When you crank the engine the PCM should see RPM and is doesn't, IE: crankshaft sensor.
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Tuesday, October 29th, 2024 AT 2:19 PM
Tiny
BOREWASH
  • MEMBER
  • 8 POSTS
Yeah, but surely I’d test the wires and connectors going into the crankshaft position sensor before changing the PCM? By the way they test good. I don’t understand your random diagnosis. So I’m thinking it could be immobiliser? Why would you rule that out? Am I missing something?
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Tuesday, October 29th, 2024 AT 4:53 PM
Tiny
BOREWASH
  • MEMBER
  • 8 POSTS
Key - Ignition - immobilizer - crank - ecu, injectors / coil. That’s the right order I think? Why do you think ECU is dead? I’m confused.
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Thursday, October 31st, 2024 AT 3:21 AM

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