atheadwins

iTrader: (3)

Hi all,

I'm a complete idiot.

I have been putting my GSLSE back together from being completely stripped down. The stupid part was stripping everything off over a year ago... Including relays etc etc etc.

I had the engine harness and driver's side harness all put together, starter harness bolted on. I was trying to get all the relays in place and I wanted to see if the fuel relay would kick on when I turned the key.

My ignition switch is not a stock one, the old one went out, I have an ignition switch from RockAuto that has always worked great, however, I had to wire it myself because none of the plugs fit.

So I turned the key and thought I heard the relay click, turned it again and heard a click... Started smelling something... Turned the key again and realized something was starting an electric fire... Couldn't find it anywhere, then saw smoke coming from under the ECU kick panel.

I have searched all over the forum to see if this has happened to anyone else and there are no results. Has anyone had this happen?

I need to take some time and go through the FSM to find where I screwed up (likely a relay, or wired the ignition switch wrong somehow).

atheadwins

iTrader: (3)

I had to share this... I went and saw a mechanic with a running GSLSE, I am an idiot and plugged one of the relays (metal top) from the drivers side in on the passenger side, I am not sure if this is what caused the short. I will also be looking to make sure all ground are in the right place.

Peace,
Al

atheadwins

iTrader: (3)

Hopefully this can be a resource for future use. I have absolutely no idea how this keeps happening, electric is not my strong suit, however, I am willing to learn to make this car run. I asked a factory trained mechanic in town what I may have done wrong and he said "never heard that one before" I don't like to bother him with these things as he stays busy with Formula Mazda cars and I think its disrespectful to bring my crappy project in and ask him to fix it.

I moved the aforementioned relay to the correct side of the car and ordered 3 new to me N304 ECU's.

Before all this was happening the car ran great... that was a little over a year ago, for some reason I stripped the whole damn thing down to the chassis and I am just now getting it put back together. The only modifications I have made are suspension/fuel and they should not affect the ECU, the fuel pump is wired up with a switch direct to battery. The car is a GSLSE with a street ported engine. Some of the engine ancillaries were exposed to rain in the time apart, however, alternator and starter have been tested perfect. Since I am just getting everything back in (including the harness) it would make sense that I may have plugged some things in the wrong place.

I installed one of the new ECU's today and completely by accident managed to power the car and burned the ECU up in the exact same way as the first one.

I have taken some pictures and tried to do as much research as possible to look for answers.

There are two transistors burning up T011 and T511.

What I am going to work on tomorrow is refreshing all the grounds in the car, specifically the engine and battery harness grounds. I need to also go through the FSM and trace the path to every single relay to ensure I haven't plugged some things in the wrong place. I should also try to find what pin these transistors lead to and see if that helps answer the question.

The other thing I found in my research was some Honda guys having ECU's burn up transistors just like this and they were crossing their intake air temp sensor and BAC/IACV plugs. This is something I will have to check as well.

ANY input is very much appreciated.

Peace,
Al

Jeff20B

iTrader: (13)

The intake air temp sensor connector is a different shape from the BAC valve, but they are in a similar location in the harness.

atheadwins

iTrader: (3)

No way I crossed them then... The plot thickens...

I have printed the wiring diagram for '85, my plan for tomorrow is to first clean up all the grounds. Then I am going to try and check for shorts in the ecu plugs in case somehow a wire is shorting in the harness (long shot), I am going to try and be patient and follow the whole wiring diagram to make sure everything is in the right place.

After all this hopefully I can plug one of the already burned ECU's back in and see if it still makes excessive heat and/or smoke.

Would you all do anything different or add anything?

Thank you,
Al

NCross

iTrader: (18)

When I unloomed my SE harness to combine it with the SA harness I noticed several wires had lost there insulation and were touching under the tape and conduit. That could be your problem. If it were me Id peel your harnesses apart and check for burnt wires.

atheadwins

iTrader: (3)

I appreciate the input... I will have to dig in to that soon..

I hate to admit it but this could go down as one of the dumbest things anyone has ever posted on the forum.

It turns out I had my battery cables switched, I had been putting power to the ground wire and vice versa.

I am hoping I didn't screw up any other electronics with this bone head move but I am pretty sure the ECU issue is taken care of now.

Heres to being wrong!

Thank you all for your thoughts.

NCross

iTrader: (18)

Surprised the main fuses didnt pop first.