How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Gary Your Own Question
Gary, Australia Car Mechanic
Category: Australia Car
Satisfied Customers: 1119
Experience:  Senior Technician
Type Your Australia Car Question Here...
Gary is online now
A new question is answered every 9 seconds

I have changed crank sensor and fuel injectors but this

Customer Question

i have changed crank sensor and fuel injectors but this problem only occurs on no 3 cylinder and my thought it would be ecu unit as this is what controlls injectors and to have so many codes at once with no engine light on is it possible to be the ecu
Submitted: 1 year ago.
Category: Australia Car
Expert:  Gary replied 1 year ago.

Hi Garry,

What make/model and engine?

Have you done a compression test on all cylinders with all spark plugs out?

Do you have injector pulse on the cylinder 3 injector plug?

Your fault could be the ECU, but I need to ask these questions first to see where you are.


Customer: replied 1 year ago.
Checked injector circuit and it was ok and when no3 cylinder completely fills up with petrol when I try to start the engine won't turn over so I removed all spark plugs only no3 had an issue and cranked engine and it forced out all the raw fuel and there is multiple codes and the check engine light doesn't stay on with codes replaced crank sensor as this was one of the codes po335-po115-po110-po123-po223 and when tried second time it happened exactly the same again I am thinking maybe the ecu is faulty as it controls the fuel injectors and by the way on the first time this happened I changed injectors thinking it might be faulty but to no avail
Customer: replied 1 year ago.
2005 outlander with 4g69 mixed engine
Expert:  Gary replied 1 year ago.


Have you got a noid light, for testing injector pulse?

Sounds like the injector circuit is on at all times, instead of pulsing.

The injector control circuit could be grounded within the harness, or the ECM is faulty.


Customer: replied 1 year ago.
I checked the wiring and it tested ok so does this mean the fault will be more likely the ecu as it controls the amount of time the injector stays open and the manual shows transistor in Ecu unit switches injector on and off and can these be replaced
Expert:  Gary replied 1 year ago.

If you have proved the engine, and all other components are ok, and the engine runs on 3 with the injector disconnected, AND a noid light stays lit instead of flashing, then yes the fault is internal of the ECM.

I would get an exchange ECM.

Repairs are out of the scope of the average home mechanic.


Customer: replied 1 year ago.
Expert:  Gary replied 1 year ago.

Hi Garry,

I hope I have been of assistance to you today.

All the best to you.