Car Won't Start Cranks, No spark.

THANVAS

MEMBER
2004 MITSUBISHI LANCER

I have a 2004 Mitsubishi Lancer. I had the car on, and I was checking the downstream O2 sensor with a voltmeter, and I accidentally shorted the probe between two leads. I saw a spark when this happen and the car turned off. I tried starting the car, it cranks but not starting. I put a spark plug at the spark plug wire and turned the ignition to check for spark and noticed that there is no spark. I checked all the fuses under the hood and inside the car below the steering wheel and they were good, so I thought I damaged the ECM, so I replaced my ECM. After installing the new(rebuilt) ECM, I tried starting the car and I'm still having the same problem. I have also checked the power going to the ignition coil and it's getting 12v. I don't know what else to check.

9 Replies

KEN L

MASTER CERTIFIED MECHANIC
47,347 POSTS

Hello Thanvas,

Ya, its happens, it sounds like you shorted the main voltage system for the sensor data buss delivered from the computer, turn the key to the "ON" position, disconnect the TPS sensor, using a grounded volt meter, see if one of the wires has about 5 volts DC, if so, the system is working, if not, check this wiring diagram below to troubleshoot, also try disconnecting all of the O2 sensors, if one is shorted it cause cause the system not to work.

Please let me know what you find, I like solving these kinds of problems,

Best, Ken

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Tuesday, April 20th, 2021 AT 11:42 AM

THANVAS

MEMBER
46 POSTS

Does the car receive the 5v from the ECM? I've noticed when I turn the key to the on position the check engine light doesn't turn on. Does this mean that the ECM is not powering up? If this is the case what can I check? I have already checked all the fuses under the hood and they were ok.

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Tuesday, April 20th, 2021 AT 11:42 AM

KEN L

MASTER CERTIFIED MECHANIC
47,347 POSTS

Hi Thanvas,

Are you testing the fuses with a test light to confirm voltage at the fuse box, also lets check for 12 volts coming into the computer, there is a main power relay, check the lower diagram you can see it in the upper right hand corner.

Let me know what you find

Best, Ken

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Tuesday, April 20th, 2021 AT 11:42 AM

THANVAS