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Jay, Certified Infiniti Technician
Category: Infiniti
Satisfied Customers: 3943
Experience:  20+years, Nissan and Infiniti experience and currently now working for a Infiniti Dealer
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Put a used motor in my M45, transferred the new cam sensors,

Customer Question

put a used motor in my M45, transferred the new cam sensors, and crank (just bought them) old motor locked up Rod knock.
JA: Does the vehicle stall at low speeds? Does it sputter?
Customer: It doesnt start , backfires ...pulled plugs and they were wet.
JA: What year is your M45?
Customer: 07
JA: Are you fixing your M45 yourself? What have you tried so far?
Customer: yes its mine, I checked all wires and grounds, it was running at time of the Rod knock then seized. replaced with used motor, scanner says post Cat o2 sensors are off
JA: Anything else you want the mechanic to know before I connect you?
Customer: scanner shows RPM as well,
Submitted: 12 months ago.
Category: Infiniti
Expert:  Jay replied 12 months ago.

Hello my name is ***** ***** thank you for your question.

Where did you buy these sensors? Also do you have any codes?

Expert:  Jay replied 12 months ago.

Did you replace the Catt Converter as well? What was the cause of the other engine failing?

Customer: replied 12 months ago.
they are infinty sensors, the catts failed and were punched out , was running fine with catt code, developed a Rod knock, seized up and never started . pulled motor
Expert:  Jay replied 12 months ago.

What you are going to want to do is inspect the exhaust and make sure it's not restricted with any debris from the catt converter failing. If the exhaust restricts flow, it will keep the engine from starting.

So I would try dropping the exhaust after the catts, just to see if the car will start and run.

Clear all codes and monitor for new codes.

Give that a try and let me know how you make out.

Also, if the spark plugs keep getting soaked, that could be due to bad gas, or low compression in the engine you installed. So that may want to be checked as well.

Let me know how you make out

Customer: replied 12 months ago.
it actually doesnt have codes, letting batt charge overnight, I did drop exhaust then pulled pugs to see that they are wet.
will run compression check in morning.
Expert:  Jay replied 12 months ago.


Customer: replied 12 months ago.
I think I have an ECU PROB.
changed plugs , removed catts.
Gonna check gas tank next
Expert:  Jay replied 12 months ago.

I hope its not a bad engine...