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Potentially ruined wiring.. need help troubleshooting.
So a couple days ago, I finally got my car ready to turn the key. All the wiring was finally done except for a few wires. The negative terminal was unhooked. I go to hook up the last few wires and obliviously hook up the heavy gauge power wire that goes to the starter to ground. When i go to reconnect the negative terminal there was a huge spark and the positive terminal became red hot. We took the negative terminal off really quickly, no more than 3 seconds, and there is no power the my ms3. Currently, the starter wire is still disconnected, the battery is connected, but as I'm trying to hook my megasquirt up to my computer, absolutely nothing is happening. When i put the key in I get beeps, parking brake light, odometer, and my headlights work.. Where should I even begin troubleshooting to figure out what is up? I took yhe megasquirt out to see the circuit board, but I'm not sure what to look it. This is a 1999 and I'm trying to hook up a rev built ms3 basic I bought from someone on here. Thanks.
The main fuse would likely blow before damage to the main relay. Sounds like the battery was just shorted straight to ground through the unfused starter wire. Seems odd that would have damaged anything other than that unfused wire actually.
Did the MS3 connect to your computer properly before?
Do you have a DMM to test for power at the ECU connector?
I pulled the main fuse and it looks okay. I don't have my meter at home and can't get it until Monday.. I may go out and buy another just to try it. Yeah i got the ecu secondhand and have not been able to personally get it running yet. I checked again to make sure all my connectors are hooked up and they seem to be so I suppose it has to be fuse or relay related.. I plugged the factory ecu in just to see, though, and I got the exact same result. Just odo and lights.
So I checked all the fuses, hooked up the starter wire, checked a ton of wires just to see if i had power around the car and I literally I have power everywhere except for the green plugs that plug into the ecu. Can anyone explain this? Frustrating me pretty bad.. I can't wait to drive this car.
Have you contacted Rev? Sometimes he's hard to get ahold of, but he knows his units inside and out and can usually troubleshoot stuff like this fairly quickly
Use the link I gave. Scroll to the bottom and click on the 99-00 diagram. It shows the power wire for the ecu as violet/red. The wires on either side of it are orange and white/blue. Are you saying that wire is showing continuity to ground with the MS3 unplugged? To clarify this is the vehicle wiring I'm referring to.
Are you also saying that wire isn't being tied to the MS3 DB37?
I havent contacted him yet. I know i have in the past and got no response though. & I found that wire for sure. Something must be going through the megasquirt. That wire shows nothing when unplugged, key on and off. When i plug it in it shows ground with key on and off. This makes me think the ecu is messed up. I did find a couple wires in those three plugs that have 12v..
I havent contacted him yet. I know i have in the past and got no response though. & I found that wire for sure. Something must be going through the megasquirt. That wire shows nothing when unplugged, key on and off. When i plug it in it shows ground with key on and off. This makes me think the ecu is messed up. I did find a couple wires in those three plugs that have 12v..
1B white/red should also have 12v. I missed that when I skimmed the diagram.
You should figure out why you don't have power on violet/red before you assume anything about the ECU. Check you fuses properly. Measure for voltage on both sides.
you can jump power across the relay connector to confirm it is at fault. you also need to make sure that the relay is getting the request to turn on.
Power comes into the relay on the Green/red wire which is supplied by the 30A injector fuse. Once active, it passes that power on to the white/red wire.
The signal to activate the relay comes from the 15a engine fuse which is hot when the key is in the start or run position.
Okay sounds like my main relay is bad. I'll get one on the way and see if that fixes the issue. Fingers crossed..
You're making an assumption the relay is bad all on your own. What you originally did with the starter wire wouldn't kill the main relay IMO.
Just use your damn meter and test. You could have this figured out in minutes. Brain's diagram shows 3O and 1B should both have constant power. You already said 3O doesn't. Have you even checked to see if you have power at 1B? If you don't have power at 1B then work back to the relay and main fuse.
As was mentioned you can just use a jumper wire instead of trying a new relay.
You're making an assumption the relay is bad all on your own. What you originally did with the starter wire wouldn't kill the main relay IMO.
Just use your damn meter and test. You could have this figured out in minutes. Brain's diagram shows 3O and 1B should both have constant power. You already said 3O doesn't. Have you even checked to see if you have power at 1B? If you don't have power at 1B then work back to the relay and main fuse.
As was mentioned you can just use a jumper wire instead of trying a new relay.
That diagram on trubokitty is misleading. if you look in the chassis schematics, you will see that 3O V/R goes directly to the IAC valve and does not split off to anywhere else. 3O should be the 12v supplied by the MS out to the IAC and not a 12v input.
That diagram on trubokitty is misleading. if you look in the chassis schematics, you will see that 3O V/R goes directly to the IAC valve and does not split off to anywhere else. 3O should be the 12v supplied by the MS out to the IAC and not a 12v input.
You're absolutely right. I didn't have access to a proper diagram last night.
08-12-2017, 08:37 PM
Potentially ruined wiring.. need help troubleshooting.
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