I helped landlord who got a 2009 Nissan Maxima sedan car that was towed to landlord's yard and he did a compression test, 1 was 90, 2 was 120, 3 was 95 and 4 was 150. He replaced all the spark plugs and ignition coils and spark plug wirings. The engine has a rough idle and will shut off. I did a code read test at 2k rpm and got 5 codes: P0300,P0301,P0014 and P0024. He said it needs a new alternator. The vehicle has 200986 miles. I thought the car reached end of life and landlord is wasting money to try to fix this car.
Those compression readings indicate the engine is probably worn out. That being the case there can be no expectation of it running properly. Unless he is ready to rebuild the engine (not worth it) he is wasting time, effort, and money.
You are correct.
I am not an mechanic but it's an good idea to use a 500 bucks xtool code scanner instead of 35 bucks autel code reader i have to check an used car before buying?
The more data you can gather and tests you can perform on a used car the better, however you also need to learn how to interpret the data and use the more advanced functions. It would probably be better to pay a good mechanic, who has a fancy scan tool and knows how to use it, to do a thorough inspection.
Thanks for the answers. I am not an mechanic but it's an good idea to use a 500 bucks xtool code scanner instead of 35 bucks autel code reader i have to check an used car before buying?
click on "Car Questions". At the top you will see that the first topic is, "Which Scan Tool Should I Get?" This should help you.
I have been watching YouTube videos of how the mechanics use the scan tool and diagnose the engine issues. I know of an mechanic that can check used cars.