So today as I was pulling through a light in second gear i noticed the cel flash for maybe a second then turn off. Then I noticed a burning smell like when electronics are burning, but the car was still running fine and the cel never came back on. I checked my ecu...i smelled it... and it seems like the smell i was getting was coming from it. However since then i have driven 30 miles without a problem. I checked that the cel does work and it isn't throwing any codes. Any ideas as to what could have caused this luckily i have another ecu sitting under my seat so i wouldn't be stranded if it did fail on me but I am really curious why it would have done this. I opened up the ecu and by the plugs there is a burn mark like you can see in the pic on the back there was also a solder that looked like it overheated it's sort hard to see in the pic but it's the one darker than the rest about two inches to the left of the screw that's towards the center. Do you think the ecu is fine since it's not throwing any codes i don't know what to do

 

bump does anyone know if that will effect anything it looks like it came from the brown cylinder...what does that effect, i know very little about boards like thsi other than resistors and the other basics

 

the cap (capacitor) is blown. they dry out over the years .. so they do have a lifespan. I would go to radio shack and by the exact same # cap and solder it in.... or get a whole new ECU.

 

Personally I would buy another ECU. It looks like a capacitor that went out, but no matter what it is, it isn't going to perform like it should with all of the parts working correctly. I wouldn't take my chances.

 

you can look at the part number and goto radio shack and buy a replacement. desolder and resolder new cap... good as new

 

what is that capacitor for? how did it happen? to big or small wires ghetto wired?

 

that's what i would like to know as well. It is a virgin p30 it isn't because of a chip or anything. As far as wiring in the car goes there aren't really any problems it was kinda messy when i got the car but i went through everything and soldered/heatshrinked any connections that the po had made. I am gonna hope that the problem was like someone else said that these capacitors can go bad over time ill just try to re solder one in. If i screw it up like i said i have another ecu so it wont be the end of the world. Obviously there is something wrong with the way it is currently so it can't get worse, it just doesn't seem to be affecting anything super obvious. Thanks for the replies guys ill let you know how the soldering goes...maybe post some pics if I am proud of my work haha

 

trace the back of the ecu (the lines) to an ecu pin..see if that does any good,
jus a guess

 

i don't think its the wires going to the ecu the other one i ran in there for like three months never did that. I took the old cap out and it had burned a hole in the board so that ecu is pretty much shot, a lot of the copper around it was melted too

 

practically, its not shot. as long as no other leads on the board were destroyed

you can solder on a new capacitor without soldering it to the board, just run some small wire > solder them to the cap > scrape off to get access to the leads and solder the wires to them

if no other leads were damaged by the burning (which you can examine and find out easily) then soldering the capacitor on this manner should work like normal

 

yeah well i don't think i am gonna go to that trouble it's hard to see where the lead for it goes because it kinda burned a lot everything under it is gone and some around it. There are two leads it could be for. I think I am gonna just keep running this p28 i bought the p30 to see if my mpg would be better and it isn't if anything it seems worse and it seems to run the engine a lot worse than then the chipped p28 which is kinda weird. Kinda suck cause i can't really sell the p30 know which was what i wanted to do...there goes two bills.