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so i had a shortage in my evo. burned out a a few grounds. i replaced the ground cabled and everything seemed fine. however the coil pack in cylinder 2 was blown. it had a huge buldge on it. so i replaced it. and i still had no spark from that pack. i swapped the coil packs just to make sure. and it for sure wasnt the coil pack. i did some testing. and found out that this cable isnt preforming as it should. what should be my best plan of action?replace the cable ? or get a new harness ? (green cable doesnt work)
That green wire goes back to the ecu and is what controls the coil. You should do a continuity test on the wire from the ignition coil harness to the ecu connector. It should read extremely low resistance. You should also do a continuity test from that pin to chassis ground, and it should be very high resistence (if it reads anything at all). If you don't get continuity to the ecu, or you do get continuity to ground it's probably the harness. If you do get continuity to the ecu and none to ground then it could be an issue with the ecu itself.
That green wire goes back to the ecu and is what controls the coil. You should do a continuity test on the wire from the ignition coil harness to the ecu connector. It should read extremely low resistance. You should also do a continuity test from that pin to chassis ground, and it should be very high resistence (if it reads anything at all). If you don't get continuity to the ecu, or you do get continuity to ground it's probably the harness. If you do get continuity to the ecu and none to ground then it could be an issue with the ecu itself.
The numbers are no where near as similar as to the cable on the coil pack that does work. if its just the harness. can u just replace that once cable ? or would i have to get a new harness ?
The numbers are no where near as similar as to the cable on the coil pack that does work. if its just the harness. can u just replace that once cable ? or would i have to get a new harness ?
Pin 23 at the ECU is that wire, you can do as stated above by testing continuity, but if you don't have much experience with, or have, a multimeter you can just cut and run a new wire to the connector from the ecm pin and see if you have spark.
Obviously it's back to the drawing board if that doesn't work.
The numbers are no where near as similar as to the cable on the coil pack that does work. if its just the harness. can u just replace that once cable ? or would i have to get a new harness ?
Yes you could replace just the one wire. It's going to be a PITA, but not much different work load than replacing the harness. You can purchase new pins from spoolinup or mouser.
That green wire goes back to the ecu and is what controls the coil. You should do a continuity test on the wire from the ignition coil harness to the ecu connector. It should read extremely low resistance. You should also do a continuity test from that pin to chassis ground, and it should be very high resistence (if it reads anything at all). If you don't get continuity to the ecu, or you do get continuity to ground it's probably the harness. If you do get continuity to the ecu and none to ground then it could be an issue with the ecu itself.
I did both tests for the cable. for continuity i got no results. i did the same test for the other coil pack and it didnt read anything. but i know that coil pack works because ive seen it spark. for the ecu. i see no visible damage and it doesnt smell burnt.
No you want to test with both ends of the harness unplugged. Just to be sure we are on the same page, you want to put the meter in the mode where it beeps when you touch the two probes together. One probe on the ignition coil side of the harness, and the other on the ecu connector side of the harness. It should also show resistance on the display. Make sure you are getting the correct wire on the ecu side of the harness. Do you have a 4 plug ecu or a 3 plug? To ensure you are getting good contact on the pins what I will usually do is de-pin the harness and use alligator clips on at least one side of the harness. Even with a trusted helper, getting good contact with the probes through the connector can be a bit dodgy. Sorry If this is all trivial for you, no way to really tell where anyone is at electrically over the web.
If you are sure you have the right pins ( you can sweep across all the pins looking for that beep if in doubt ) and you still get no beep, you have a problem with the harness. The signal wire from the ecu to the coil does not carry current. The ECU sends a ground signal to the coil to tell it to fire (active low in electronics jargon). So even if that wire did short to ground (which you would get a beep from the harness to chassis) it wouldn't get hot or smoke or anything like that. Shouldn't anyway...... if it shorted to something carrying current...well that would be a different story.
i have used a mulitmeter and its helped me before but by no means im expert. I have a 4 connector and used this diagram. I think my best bet is to run all the pins. I also know that the 4th connector has power (not sure if thay helps my case or not) and just to be sure. my ecu shouldnt be fried if my cable did ground itself ?
Aug 19, 2021, 09:08 PM
