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K. Wiggins
K. Wiggins, ASE Certified Technician
Category: Mitsubishi
Satisfied Customers: 2587
Experience:  AA in automotive Technology, 15+ years in the trade
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My 2003 mitsubishi eclipse spider gs 2.4 burned the coil

Customer Question

my 2003 mitsubishi eclipse spider gs 2.4 burned the coil closest to the driver side i switched them and burned the other one. i bought new ones and installed them and it did not spark or do anything.when the first coil went i thought it would litterally catch fire. what is happening?
Submitted: 1 year ago.
Category: Mitsubishi
Expert:  K. Wiggins replied 1 year ago.

When the first coil went like that it should of blown the 10 amp "multi purpose fuse" which would explain why it will not fire now.

The coil may have shorted internally or the wire that goes from that coil to the computer may have shorted to ground as well as the driver for the coil in the computer may have failed.

Do you have a multimeter handy so we can check a few things? Also is the car a manual or auto, so I can pull up the proper diagrams.

Customer: replied 1 year ago.
Have multi meter car is a 5 spd
Expert:  K. Wiggins replied 1 year ago.

Great, lets start by checking for power to the coils. Each one has a black and white wire that powers it. With the key on check for voltage on that wire at each coil and let me know what you find.

Customer: replied 1 year ago.
Got nothing from the black and white wire, where is the 10 amp fuse
Customer: replied 1 year ago.
Changed the 10 amp fuse that was blown under the dash . we have power to cylinders 1 and 4 .but still no powet to the middle 2
Customer: replied 1 year ago.
You still there ?
Customer: replied 1 year ago.
Drivers side coil has power on a solid black wire but neither coil has power going to the black and white wire
Customer: replied 1 year ago.
I need some help with this?its been over an hour
Expert:  K. Wiggins replied 1 year ago.

I apologize, I steppeed out for lunch.

Solid black wire is ground. If there is power on that wire while unplugged from coils it has shunted to power via a wire in the harness. you may beed to pull back the conduit and inpect that wire.

No power to the coils on the black and white wire means you need to check fuse 24 in the inisde fuse box its 10 amp and is the multipurpose fuse.

Let me know what you find and I can help you further. I will respond as quickly as I can.

Customer: replied 1 year ago.
Okay i replaced that fuse and im getting power to both of the coils but it still wont start
Customer: replied 1 year ago.
The coil closest to the drivers side is getting power to 2 out of 3 wires
Customer: replied 1 year ago.
The outside two .the black and white one and also one of the black ones . the passenger side is onky getting it to the black and white wire
Expert:  K. Wiggins replied 1 year ago.

OK, it's not starting due to problems on the ground circuit of the coil. The one that has power on the black wire should not.

Unplug both coils and se if you have continuity to ground on the one that does not have power on the black wire.

If you do, cut the black wire on the coil that has poer on the black wire and then using a jumper wire ground the black wire you cut on the coil side of the wire.

It should have spark then. Let me know what you find

Expert:  K. Wiggins replied 1 year ago.

Here's a wiring diagram for you. It's not the clearest but it's somewhat legible.

I have to step back out for another 15-20 minutes, will reply ASAP

Customer: replied 1 year ago.
We didn't get any spark but it lit up a test light . the coil that its been plugged into is hot while the other coil is cold . the black wire is drawing 9 volts while the black and white one is reading 12
Expert:  K. Wiggins replied 1 year ago.

with both coils unplugged you have the 9 volts on black correct?

Customer: replied 1 year ago.
I'm sorry it is the black wire with the blue tracer that is showing 9 volts earlier I told you it was the black wire I'm just getting so frustrated with everything looking the same color I'm sorry. We have peeled the wiring harness back almost to the box where the ECU plugs in and all the wires look fine and all those wires look fine to that point.
Expert:  K. Wiggins replied 1 year ago.

Thanks for clearing it up. I know how frutrating electrical stuff can be.

The black wire with blue tracer is what comes from the computer to signal the coil to fire.

Here's what you need to do to check that wire. Disconnect the ecm connector and the connector at that coil. The voltage should go away on that wire. Then ohm it from the computer connector to the coil connector. It should read less than 5 ohms. If both the above check good then the coil driver part in the computer is bad like I emntioned earlier and it will need to be replaced.

Expert:  K. Wiggins replied 1 year ago.

It's pin 10 at the computer connector

Customer: replied 1 year ago.
We still have 9 volts on the black wire with blue tracer with the ECU unplugged and both coils unplugged also I'm not sure which pin is number 10 I don't find any numbering anywhere that would tell me
Expert:  K. Wiggins replied 1 year ago.

Thanks, ***** ***** unplugged and still showing voltage it's for sure damaged and picking up power from another wire.

Unfortunately I do not have a picture of the pin outs at the computer connector. What I suggest is starting at each corner of it and counting over to the tenth pin, you'll know it's the right one when it's the black and blue wire.

Expert:  K. Wiggins replied 1 year ago.

Also try pulling the fuse that you replaced and see if the black and blue wire loses power with it all unplugged. I have seen connectors go bad internally and let other wires pick up power from a wire with voltage.

Customer: replied 1 year ago.
When we pulled the fuse the black and blue wire still has 9 volts but the black and white wire has none
Expert:  K. Wiggins replied 1 year ago.

That's how the black and white wire should be.

The black and blue still having power with the fuse out lets us know the connectors at the coil are not bad.

There's two ways you could go from here.

1. Remove all the conduit from the harness and check to make sure the black and blue wire is not touching anything where it has a raw o melted spot.

2. Cut the black and blue wire about 3 inches from each connector and replace it with a new wire.

If nothing damaged the computer when that coil failed it should then start.

I know both routes are a pain and time consuming but that's what will need to be done.

Customer: replied 1 year ago.
Ok we cut 3 inches from the connectors replace the wire we now read 11 volts now we've looked under the dash for any dangling wires or anything like that and nothing is changing it other than now its 11 volts so I assumed wherever the short might be and it's given feedback and making it to the black wire with the blue tracer to this point we've not been able to figure anything out.How much are we being charged I'm uneasy.
Expert:  K. Wiggins replied 1 year ago.

It looks like the total cost of your question is 18 from my end. I'm honsetly unable to help further without actually being there at this point.

I'm going to open this back up and see if another expeert has any input.

Customer: replied 1 year ago.
18 is what I understood I just wanted to make sure. I've been baffled with it I've done this stuff before but this has been the most frustrating for me when we replace the wire and read 11 volts i about fell over I don't know what it is unless its feedback from something else I don't understand how it can be I just don't understand

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