Alright, my main question is,.... i can go back to running a P28 stock by simply cutting the J1 jumper correct? It should run stock fine right???

anyway, my problem is that i have j1 disconnected to check to make sure the ECU works before i play around with uberdata. My car runs in limp mode with the check engine light blaring. So i'm tyring to figure out if simply having a chip in there will throw it off, or if i HAVE to have jumper J1 connected.

Again, I am just looking to run this ECU stock to verify it works.

Thanks!

 

Tken from the Uberdata FAQ:

"Notes: Caution: If you plug in an EPROM or EEPROM backwards it will overheat and erase or damage the device. Use a 27C256 ROM, same as OBD0. If you are getting an error that was not there with the stock ECU, write the appropriate stock .bin file to a blank chip and install in your ECU. If there is still an error, there may be a soldering problem. Cut J1 to return the ECU to stock."

 

alright, a little update:

I had J1 disconnected, car was in limp mode i believe. THen i connected J1 for the hell of it, put in my burned rom. Then the car wouldnt even start. so i disconnected J1, and the car still wouldnt start.

What the heck is going on? ???

 

I have actually put toggle switches in the j1 postion. Just pull the fuse for the ecu memory (same as clock/radio memory under the hood), wait a few minutes, flip the switch, replace the fuse, and your done. The ecu I am running right now is done this way. No problems. I can go between stock and mod program in 3 min.

 

so basically i have a bad ecu?

 

Take the ecu out of the car and inspect it very well. Look at all your solders. Make sure that the jumper is completely cut and if you clipped completely out, make sure no little piece of it is in the ecu anywhere. If you clipped the jumper with the ecu still plugged up in the car, you can kiss it good-bye. Pull the ecu fuses under the hood, if you have jumpered the diagnostic connector then pull that out, and plug the ecu back up (with the covers on it). Replace the fuses, wait a minute or two, turn the ignition on, wait to see if the fuel primes and all the dash lights act normal, then start the car. Sometimes a bad ecu will light the check light but won't throw any codes at all when you put it into diagnostic. The ecus are tougher than people think, but if you messed with it with power connected tough luck.

 

do you have to disconnect the battery cable even just to unplug the ECU? I definitely never even had the cover off it while it was plugged in.