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Hi guys, I've been on a series of bad repairs on my 2004 Nissan Maxima since December last year, and it appears no one has been able to identify the actual problem of my car.

First an foremost, my car was parked for a period of 6 to 7 months, due to a knocked engine. Up till December last year (2019), I then replaced the entire engine. Just immediately after the replacement of a new engine, the car then kick's and starts properly, then hesitates when trying to accelerate, when it finally forces it's way up the throttle, it produces a loud shooting sound then jerk's itself off.

The car had been diagnosed and part of the failed results were that, I changed the fuel pump, air flow sensor, throttle sensor, yet it still gives same results. The last thing I have been told to buy again after another diagnose was one of my coils (number1) and my crankshaft sensor.

Please I badly need an experts advise on this. I am tired of buying parts that are not linked to the solution of the problem.

Please what do you guys think the problem is?
 

Sup Mod keeping the peace
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One of the first things to do is perform an ECU code readout with a portable scan tool to see if any fault codes are set. The tool can be purchased at most auto parts stores or online at Amazon.com. Post the actual codes here on the forum so that we may be able to help you further. If there is one or more fault codes set, they can help point to the malfunction. If you have a copy of the FSM for your vehicle, the code readout procedure is described there along with a listing of codes. You can download a copy of the FSM from this web site: Owner's Manuals. The section EC.PDF is the one you need to read.

Here are some things you can test:
  • - Make sure you have a clean set of spark plugs.
  • - Test ignition: Pull several coil packs to test; use a spare plug in the coil pack to test; ground the plug base with a jumper wire to the engine block; see if you're getting a good blue spark while trying to start the engine.
  • - Perform a compression test on all cylinders. Standard - 185 psi, minimum - 142 psi, difference between cylinders - 14 psi.
  • - Perform a fuel pressure test. Tee-in a temporary fuel pressure gauge between the fuel feed hose and the fuel rail. The reading at idle should be around 51 psi.
  • - There may be a major intake system vacuum leak: To check the intake system for a vacuum leak, attach a vacuum gauge to a full vacuum source. With the engine fully warmed up, the reading at idle should be 18 - 20 InHg. At 3,000 RPM, it should be around 21 InHg. If readings are under 18 InHg, check the intake manifold nuts to make sure they are tight. The gasket may have failed; spray a water mist at the gasket to see if the gauge reading changes. Also check the intake plenum bellows at the throttle valve and at the MAF for cracks or loose clamps.
 

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Discussion Starter #3
One of the first things to do is perform an ECU code readout with a portable scan tool to see if any fault codes are set. The tool can be purchased at most auto parts stores or online at Amazon.com. Post the actual codes here on the forum so that we may be able to help you further. If there is one or more fault codes set, they can help point to the malfunction. If you have a copy of the FSM for your vehicle, the code readout procedure is described there along with a listing of codes. You can download a copy of the FSM from this web site: Owner's Manuals. The section EC.PDF is the one you need to read.

Here are some things you can test:
  • - Make sure you have a clean set of spark plugs.
  • - Test ignition: Pull several coil packs to test; use a spare plug in the coil pack to test; ground the plug base with a jumper wire to the engine block; see if you're getting a good blue spark while trying to start the engine.
  • - Perform a compression test on all cylinders. Standard - 185 psi, minimum - 142 psi, difference between cylinders - 14 psi.
  • - Perform a fuel pressure test. Tee-in a temporary fuel pressure gauge between the fuel feed hose and the fuel rail. The reading at idle should be around 51 psi.
  • - There may be a major intake system vacuum leak: To check the intake system for a vacuum leak, attach a vacuum gauge to a full vacuum source. With the engine fully warmed up, the reading at idle should be 18 - 20 InHg. At 3,000 RPM, it should be around 21 InHg. If readings are under 18 InHg, check the intake manifold nuts to make sure they are tight. The gasket may have failed; spray a water mist at the gasket to see if the gauge reading changes. Also check the intake plenum bellows at the throttle valve and at the MAF for cracks or loose clamps.
I am really grateful for your response. Thanks so much.

Here is a screenshot of the ECU fault codes..
 

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Sup Mod keeping the peace
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From looking at your attachment, it shows 7 pending codes. Active codes are live codes or malfunctions that are keeping your Check Engine Light on. Pending codes mean that the OBD-II monitoring system has failed the operation of an emission control system at least once and if it fails after some number of times, the Check Engine Light will be turned on and the malfunction becomes an Active code.

What this seems to demonstrate is that there may be a general electrical problem with your vehicle. Some of the common causes are a malfunctioning charging system and bad ground connection points which can cause some of those 7 pending codes to be false.

A properly working charging system puts out about 13.2 to 15.0 volts, but this is a general spec, and the factory service manual should be referenced for the correct charging system voltage specifications for a particular vehicle. A battery should have a static charge of 12.2-12.6 volts. If a battery is not good, the charging system may not be able to charge properly. When a charging system is not charging, or overcharging, a lot of "strange" things can occur. It's not uncommon to see a multiple of stored trouble codes in the ECM memory. So, whenever a vehicle is setting a multiple of trouble codes, idling funny or stalling, or anything out of the "norm," test the charging system before you start pulling hairs!
 

Nissan Enthusiast
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I will say this Rogoman, you and SMJ999 are the treasures of this forum. Neither the Subaru or Honda forums I look at have anyone with the amount of experience and expertise you guys do. I know I am hijacking this post, but I just want to thank you both for the effort you make in helping people and to thank you for the role you have played in my automotive education over the past number of years. I am sure others feel the same way.
 
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