Ecu/wiring problem

[mambastu]

Hi all,

Just coming to the end of my R33 GTS-T RB25DET into S13 conversion and I'm having a few last minute electrical problems

Finished fitting the engine last Friday. Fired it up and it started immediately and ran for about 15 minutes untill it was warm at which point we switched off the engine. Checked all the fluid levels and fired it up again. Within 30 seconds we noticed smoke coming out of the ECU and then the engine stopped running.

Turned everything off and pulled the neg wire of the battery. Opened the ECU and found that a resistor was badly burned (R420) and a transistor (T450) was burnt so badly it had seperated from the board. Bugger

Checked the various connections and everything appeared to be fine although there were a couple of cut wires that may possibly have earthed to the inner wing but we weren't sure.

Managed to get hold of another ECU and tried it today. Plugged it in, turned the ignition key, fuel pump primes for about 5 seconds and 10 or 15 seconds later the same resistor (R420) starts to smoke. Checked all the pin outs on the ECU and everything looks fine.

Has anybody experienced this before and if so how can you tell me how you fixed it please ?

[Jay95R33]

Sounds strangely like what I did when I blew my ECU

http://www.skylinesaustralia.com/forums/sh...read.php?t=4320

Cooked a resistor and melted a transistor off of the board !!

I stuffed up and shorted out the tacho output. Did your tacho work while it was running ? Try cutting the wire to the tacho output and see if it does the same thing.

I 'might' still have some pictures at home of the inside of my blown ECU, if I can find them I'll post them up and you can see if it's the same resistor and transistor.

J

[mambastu]

If you can find them it would be really handy, thanks

[Jay95R33]

Damn - can't find them. I must have deleted them

If I remember right, the resistor that burnt out was on the side with all the other components, while the transistor was on the other side where it's mostly silver track and soldering.

J

[mambastu]

Thanks for looking anyway. Sounds very similar to the problem we have. The transistor is on the back of the board like you say.

Looks like the blown resistor does pinout to the tacho wire although we didn't think that the wire was actually connected to anything.

We'll check into it a bit further, might be the clue we're looking for. Thanks again.

[mambastu]

Found the fault at last. Looks like the engine loom had taken an impact and 1 wire was completely severed and another 3 (including an ignition feed) had damaged insulation and they were obviously shorting. There were no obvious external signs of the damage, we were quite lucky to find it !

[Jay95R33]

Ahhh, good stuff Stu.

Good to see you found the problem

J