I have a 2004 Landrover Discovery 2 SE. I was having a missfire in cylinder 3 and after closer inspection noticed that the fuel injector was dumping fuel into the cylinder even when the car was just turned on to accessory mode. I replaced the fuel injector and after that didn’t fix it, I sent the ECU away to get fixed. They repaired it and I plugged it back in. The car worked for a day, but then the ECU fried itself again and the same problem came back. Any insight as to what could be causing this? Any advice is appreciated. Thanks

Trouble codes I’m getting
p0150
p0300
p0303
p0267

 

P0267 Cylinder 3 injector circuit low; Injector 3 short circuit to earth
P0150 O2 sensor circuit malfunction (bank 2, sensor 1) This is not the same bank as cylinder 3
P0300 Random/multiple cylinder excess emissions detected
P0303 Cylinder 3 misfire detected

It seems that the circuit for Injector 3 is shorting making it constantly open. When you sent the ECU away to get fixed, was there a specific issue that they found and fixed? It is possible that they did a poor job at fixing the issue, or maybe the ECU is fine.

I think it is likely you have broken wiring somewhere that is shorting. Possibly intermittent causing it to work for a day with the fixed ecu. I would take the upper intake off again and follow the wiring looking for issues. Use a multi meter and check the injector plug (car side) to see if there is a short to ground. Then unplug the ECU and see if the short remains. If it does not, then the ECU likely has the issue.

 

The shop that repaired the ecu said there was a blown capacitor on injector 3 that the fixed.

I’ve taken the intake off again and inspected the wiring harness but couldn’t find any visible damage to it.

 

According to the electrical circuit diagrams https://discoii.wordpress.com/wp-con...grams_2000.pdf page 20.4, the fuel injector has one wire that connects to positive and is shared with the other injectors, and the other connects directly to the ECU which is a controlled ground and turns on and off when the injector is supposed to be pulsing.

Since you had a blown capacitor on the ECU, your current problem is either one of two things.

1. The repair failed, and the ECU needs to be sent back.
2. Some (possibly intermittent) short causes the capacitor to blow.

The short could be inside the injector, but since you replaced it this is probably not the issue. Double check you replaced the right one.
I would use a multi meter, and check that the injector pin that connects to the ECU is not shorted to negative or positive. It is possible that you have wiring issues farther down the line where you can not see it, however, this is less likely, and im thinking you just need a new ECU, or to send this one back to repair. The should have a warranty and fix the issue for free. You could also open it up yourself to see if anything is wrong.