Nissan Repair Questions? Ask a Mechanic for Answers ASAP
Hello my name is ***** ***** thank you for your question.
Did you get those cam and crank sensors from the dealer? Do you have a Service Engine Soon light on now?
First things first. When it comes to these Sensors stick with the dealer. After Market Sensors never work right. Was the car doing this same thing before the sensors were replaced?
If you have oil in the spark plug tubes, you will need to change the Valve cover gasket and spark plug tube o-rings.
This is most commonly a Mass Air Flow sensor issue. But do not get it after market. After Market ones never meter air properly. Get the Sensor from the dealer.
At the same time, get the Cam and Crank Sensor from the dealer. I am sure if you read Online that you will find to stay away from After Market Sensors.
Do you have any more questions on this?
If you removed spark plugs, oil could have seeped into the cylinder. You need to disable the fuel system if you are doing a compression check. Fuel can enter the cylinder and wash out the cylinder walls which lowers compression
What do you mean you pulled the injectors? You unplugged them?
What brand spark plugs do you have in the car and how many miles are on it?
Did the car just stop running out of the blue. How long has the car been like this?
So the car runs right? So it can't have 130 psi of compression.
Ok.. I get that. So compression is not the problem. If it was, it wouldn't run at all.
Do you find that it will accelerate if you accelerate lightly? But if you accelerate to hard it bogs?
That is normally a Bad MAF sensor..
Were you getting the Bogging at 2k rpms?
What year Altima is the MAF sensor from?
Do you know if you have any current codes?
Did you try the MAF sensor from the Sentra in the Altima to see if it operated properly?
Try that and let me know..
I Will be back in 20 mins..
Back... Let me know how you made out..
Perfect. Good test!!
The next thing that I would check is if there is a exhaust restriction or if there is a fuel pressure problem..
Well for fuel pressure, you need a gauge.
For the exhaust, you need to drop the exhaust after the Catt and road test it and see if your power returns..
Yes, it is also the Exhaust manifold
Then I would have the fuel system checked. If you have low fuel pressure, it can cause the car to run lean and act like it's doing.
More like a weak pump. The fuel filter is part of the pump now on these cars. But I would check it with a fuel pressure gauge to verify.
If that passes, then a scanner would be needed to monitor the fuel trim to determine direction.
You need to put it in line with the fuel feed to the injector rail.
25 psi is way to low. You should be getting 56 psi. So you need a Fuel pump assembly to resolve your issue.
Really! What is the fuel pressure testing at? Where did you buy the fuel pump?
Was it a complete assembly? or did you have to take yours apart to change it?
Do you happen to have a scanner that can monitor fuel trim?
That is where we need to test next. Basically the fuel system mixture is off. That is what is causing the vehicle not to accelerate properly. Example. Before you changed the fuel pump, at 20 psi, the car was running lean cause it wasn't getting enough fuel. So now that is't getting 60, we need to see if it's running rich or lean to determine direction.
That is why I want to check fuel trim now..
You need a Advanced level scanner to do that. Those scanners are normally around 500 or better. Some bluetooth models can do it.