Have ECU probeleme!! Me so confused...wana help

[pancho y onions]

Ok i have an auto 93 hb. OK the first time i got it it wouldnt sart it cranked but no start Decided to check my ecu and i used my freainds ecu and it started right up. Gave it back to him Bought an other ecu and it turned right on.......my dad had it on for a bit and suddenely it turned off...... Back to where i started crank but no spark. Checked the ecu that was in it and noticed it had a little burn mark on it on the right side. I maybe thing something is burning the computer annd dont know what the hell it is. So im going to be checking the one i just bought and see whats happing. See if its got the same burn mark. Just would like to know if anybody knows what maybe causing it. Hope its not the harness. and wondering if that have ever happend to some one else.ThanksMR.Pancho

[All_Motor_KA]

You have a short of some kind. You will keep burning ecus.

[deviousKA]

Take a picture of the burn mark on the ecu if you can, a short or similar is most definately the issue.

Nissan ecus are not prone to failure unlike mitsubishi/mazda/and sometimes honda ecus. Sometimes with these ecus what will happen is the capacitors will leak acid or the stepper motor IACV's will seize causing heat and burnt parts in ecu. Not real common on a nissan.

[pancho y onions]

HMMM thats what i thought but not sure...........I will definatly post a pic tomorrow of the burn mark. Oh by the way thanks for the help guys.

[zerepdivad]

here's the pic so pancho will stop his crying

[pancho y onions]

Well there is the ecu. The one that i just bought has the same burnmark as the one thats on the pic. I dont know what it could be. I may be thinking it could be the ING. But i may be wrong.

[deviousKA]

Well let me first of all take a step backward with what I had mentioned before.

I have seen this problem previously but had assumed it was an isolated incident. This is an issue with the trace design on the coil power input, not associated with any wiring shorts in your harness.

You need to find another replacment ecu, you should inspect this area of the board before you purchase to make sure this is not going to be an immediate problem.

Alternatively, you can solder a wire between that large diode and the connector pin. This is a supplement power for the ecu (1 of 5 or so).

[pancho y onions]

Ok so i can soder a wire from that blue diode to the connector pin. Just wondering which is the connector pin. I really dont feel like buying ecus all the time and burning them out. and what do you mean by 1 of 5. Sorry not exactly a tech kind of person. ans cant i just change the coil.Thanks.

[deviousKA]

follow that trace to the blue connector pin and you will see it is outermost one, 4 over from the end. Solder a ~22-24 gauge wire from that pin connector the the closest lead of the large diode.

Then re install into your car and fire it up, you probably wont have a problem there again. There isnt anything wrong with your coil, this isnt an output signal but an input power.

[pancho y onions]

Is that large dioide the blue one. sorry just making sure.Thanks for the help man. Im telling ya this tech stuff is the devil haha. But thanks for the help.

[deviousKA]

Nope the black/white one next to it, on the white end. Right where you see the trace going

Also, fyi, its easier to solder the two together on the underside of the ecu. Check 5 times, solder once.

[pancho y onions]

so the one that looks like a ball. on the right side.sorry for being a pain.

[deviousKA]

The one that looks like a ball, with the blue dots on the white side.

[pancho y onions]

K got it. Thanks for the help.

[deviousKA]

Try it soon and see if it works, worse case scenario you have a problem futher up the line, there is nothing you can do about it anyways ecu would be dead.

This is just a common thing, too weak of a link, gets hot and solder pops.

[pancho y onions]

Allright i will post it up if it works....crossing my fingers.