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Edward
Edward, Service Technician
Category: Car
Satisfied Customers: 2303
Experience:  20 + years experience on various makes and models.
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Im stumped on a no start. I have fuel but no fire. checked

Customer Question

I'm stumped on a no start. I have fuel but no fire. checked cam ancd crank sensors, have RPM while cranking and no codes. Weak ground pulse on one coil and no pulse on other 2. checked continuity on harness from coil plug in to ECM and all 3 wires have continiuty on the org/blk wire @ ECM. There is a component that the grounds pass through shown on the shematic but it doesn't say what or where it is so I can test it -- car is an 03 Hyundai Tiburon V6
Submitted: 1 year ago via Mitchell1DIY.
Category: Car
Expert:  Edward replied 1 year ago.

Edward :

Hello and thanks for your question. My name is XXXXX XXXXX I will do all I can to help.

Edward :

Let me first ask, when you say you have RPM while cranking, Do you mean you can read data from the Crank sensor and it is showing cranking speed on your scanner? Also, have you got injector pulse?

Edward :

The component that your referring to that the coil grounds pass through before it gets to the ECM is just a shield. The wires don't touch it, it's to keep radio interference down.

Edward :

Also, Check voltage on RED wire at coil pack, RED should have constant battery voltage (12 volts) with key ON.

Edward :

Make sure it has 12 volts when cranking as well.

Edward :

Also, when you cut key ON engine OFF, does the check engine light come on in the dash? Also, is the anti theft light blinking fast when key is ON? Do you have a spare key to try in case it is the chip in the key?

Customer:

have constant power @ coils. Wasnt sure what that component was. the schematic shows that the gronds pass through it and it has gounds @ the cylinder head and the dash. also shares a ground with the ECM. yes have injector pulse. trying to test and rule out possibilties before condemning ECM. have data on scanner showing RPM while cranking. troubleshooter says that if cam and crank sensor aren't in synch that it wont show RPM

Edward :

It surely sounds like the ECM to me, especially if you have injector pulse. If you have injector pulse, then the ECM is picking up the correct signals.

Edward :

or Anti Theft. what about the anti-theft light?

Edward :

You have no codes stored at all?

Edward :

You've checked ORANGE/BLACK RED/BLACK AND WHITE/YELLOW wires from the coil to ECM pins 1, 2 and 3, and all showed less than .5 ohm? correct?

Customer:

where is that shield located? my concern is that when checking the harness from the 4 way connector at the coils to the ECM all the wires show continuity at the org/blk wire at the ECM but not at the other 2 coil control pins @ the ecm. Im trying to figure out if there is any common problem place where the harness could be damaged or shorted. did have a crank sensor code originally and replaced it. An oil leak had damged the wires to the sensor and all the insulation was gone. Surprised the car could have run at all before this. Replaced crank sensor and it came with new pig tail and connector attached.

Edward :

Alright, I understand, I am not positive where this ground shield is, but I know what they look like on a schematic, unfortunately my resource isn't telling me where it's located on 03 Tiburon, but, that will not make it not start, as the shield only goes around the wires, The wires don't pass through the shield electrically at all, it's only for radio interference.

I would hook a 12 volt test light to positive battery cable, At ECM pins 1 2 and 3, Get someone to crank it, your test light should flicker when cranking, indicating ground pulse from ECM. if it does, Then repair the connection from ECM to the coil pack. And it will fix your problem if you have injector pulse and fuel pressure and compression. If your showing open circuit from RED/BLACK and WHITE/YELLOW from coil pack to ECM, then that is your problem, wiggle test the harness while your ohm meter is hooked up and see if you get circuit back when shaking the harness around. If you bend the harness in one particular spot and your ohm meter reacts, then that is where the problem is, If you can't find it in 5 mins. or less, I would just cut the wire back from the ECM a good 6 inches, and run new wires to the coil pack.

Edward :

I am assuming, the anti theft system is alright, or the security light would be blinking, also would set an immobiliser fault, you said you had no codes, so that is another indication that immobiliser is OK, and no sensors are showing a hard fault.

Customer:

unplugged the harnees at ECM instead of back pinning and Im definity stumped because if the harness were smashed or damaged and all the wires were together then I should have continuity between all 3 wires at all pins. Right?? instead I can pin the coil controls at the coil connector and only have continuity on all 3 at the org/blk wire at the ECM plug in and no others

Edward :

Give that a second to load.

Edward :

Alright, click on it now. That is the diagram you have correct?

Edward :

scroll down to the bottom of it to see the ign. coils.

Customer:

im looking at the schematic. That shield or whatever it is seems to me to be where my problem would be, but where is it?? What does it look like??

Edward :

That shield does not electrically connect to those wires. if it did the schematic would have a DOT or CIRCLE where the wires intersect. Look inside the coil pack at the diagram. see the CIRCLE where the wires are spliced together. That is what a schematic looks like when wires touch. Notice they don't have that in the ground shield.

Edward :

If you unplug the coil, and unplug the ECM, you should have continuity between any of the coil control wires. They are 3 seperate wires, and should not be shorted together.

Edward :

you SHOULD NOT have continuity I should say between any of the 3 coil control wires. They should all read less than .5 on an ohm, and read infinite resistance (open circuit) when tested between them.

Edward :

How does the rest of this harness look? is it possible oil soaked the harness from the coil to ECM as well? If your not showing a good wire, I would run some known good wires from ECM to coil. and I believe it will fix your problem.

Edward :

Give that a try and let me know what happens. I have a dentist appointment today, I don't want to leave you but let me know what happens with that, I will check back in an hour or so. (I hope!) thank you.

Customer:

if theres no sontact at the shield then the only other possibilty is that the wires are smashed or pinched somewhere and 2 of them are cut between that point and the ECM. thanks. sometimes you just need to bounce it off of someone else that has some understanding and good input

Edward, Service Technician
Category: Car
Satisfied Customers: 2303
Experience: 20 + years experience on various makes and models.
Edward and 13 other Car Specialists are ready to help you
Expert:  Edward replied 1 year ago.
I understand that, Thank you Gary, Have a great week.

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