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View Full Version : ECU problems please help


Tm240sx
03-02-2017, 10:38 PM
Hello I have some technical questions about my 1991 hatch. Nothing was done prior to what i did (stock). I was digging around under the dash and noticed an alarm system. It did not work at all so i figured i would remove it, no factory wires were cut the alarm was tapped into factory wires. After removing it the car would not start. I ran the codes and there was literally nothing and after farther tests i realized the original ECM/ECU was fried. I bought a refurbished matching serial number computer from Orielly's and they said it was a plug and play so I plugged it in and reset the codes (read 55 because new ecu) so I started the car and it ran like trash. My stock Ka24de would not idle and ran really rough, I turned the car off and re-ran the codes and it gave a 34 (knock sensor) so After replacing the knock it still shot a code 34 and after farther research I found out that a bad o2 sensor can sometimes cause a code 34 to which i found a cut o2 wire and a bad sensor so i replaced it and rewired it. Started the car again and it still runs the same.
So my question is.......
1. would removing an alarm cause any of this or could it be a deeper problem?
2. Where in the stock ka24de wiring harness does the knock sensor connect?
3. Do i need to get a factory tune on the refurbished ecu or is it good?

KAT-PWR
03-02-2017, 10:42 PM
Knocks sensors are a known wear item and their subharnesses are known to become corroded. Knock sensor is under the intake manifold.

The ecu will run the car

Tm240sx
03-02-2017, 10:49 PM
When I replaced the knock the wires were snipped so I don't have a sub harness or don't know where the sub harness meets the main harness

KAT-PWR
03-02-2017, 10:56 PM
The sub harness is about 6 in long.

Tm240sx
03-02-2017, 11:00 PM
My car didn't have a sub harness at all the wires wernt there just a knock sensor that wasn't connect to anything. I need to know where the sub harness was supposed to connect to the main harness because the idiot that owned the car before me left a bunch of cut wires tapped up in the engine bay.