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Jay
Jay, Nissan Technician
Category: Nissan
Satisfied Customers: 19083
Experience:  20+yrs experience with Nissan & Infiniti Trained & Certified.Currently still working for Dealer
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Won't rev past 2000 rpms in neutral or in gear, 140000 miles

Customer Question

Won't rev past 2000 rpms in neutral or in gear
JA: How old is the transmission? Have you checked the brake switch?
Customer: 140000 miles and no
JA: What is the model of your '00 Nissan?
Customer: 2002 nissan Sentra 2.5l
JA: Are you fixing your Sentra yourself? What have you tried so far?
Customer: Yes I fixed the codes for the cam shafts position sensor and the crankshaft and put new sparkplugs and sparkplug boots
JA: Anything else you want the mechanic to know before I connect you?
Customer: Nope
Submitted: 1 month ago.
Category: Nissan
Expert:  Jay replied 1 month ago.

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?

Customer: replied 1 month ago.
No from auto zone and no I dont
Expert:  Jay replied 1 month ago.

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?

Customer: replied 1 month ago.
There is oil on the bottom of the old spark plugs
Customer: replied 1 month ago.
it was
Expert:  Jay replied 1 month ago.

If you have oil in the spark plug tubes, you will need to change the Valve cover gasket and spark plug tube o-rings.

Expert:  Jay replied 1 month ago.

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?

Customer: replied 1 month ago.
Not on the top. There is oil on the bottom in the cylinder and my compression is 130 on all the cylinders
Expert:  Jay replied 1 month ago.

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

Customer: replied 1 month ago.
I pulled the injectors when I did the compression test and the old spark plugs had oil on them and we're black the boots and the tops were dry
Expert:  Jay replied 1 month ago.

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?

Customer: replied 1 month ago.
Sorry yes unplugged them ngk
Expert:  Jay replied 1 month ago.

Did the car just stop running out of the blue. How long has the car been like this?

Customer: replied 1 month ago.
Started about two weeks ago wouldn't rev past 4000 so I checked the codes bought the sensors by the time I got the sensors the car got worse now it won't rev past 2000 I replaced the sensors and sparkplug and the car still won't go past 2000 and it has no codes
Expert:  Jay replied 1 month ago.

So the car runs right? So it can't have 130 psi of compression.

Customer: replied 1 month ago.
The car starts but it canot go over 20 meh
Customer: replied 1 month ago.
Mph
Expert:  Jay replied 1 month ago.

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?

Customer: replied 1 month ago.
Expert:  Jay replied 1 month ago.

That is normally a Bad MAF sensor..

Customer: replied 1 month ago.
Ok I put the man from my altima in the Sentra it goes to 3000 rpms then bogs
Customer: replied 1 month ago.
Maf
Expert:  Jay replied 1 month ago.

Were you getting the Bogging at 2k rpms?

What year Altima is the MAF sensor from?

Customer: replied 1 month ago.
Same year 2002 and yes 2000 rpm
Expert:  Jay replied 1 month ago.

Do you know if you have any current codes?

Expert:  Jay replied 1 month ago.

Did you try the MAF sensor from the Sentra in the Altima to see if it operated properly?

Customer: replied 1 month ago.
Just started it and tried again now it won't go past 2k and it gets loud and gargally
Customer: replied 1 month ago.
No codes and not yet
Expert:  Jay replied 1 month ago.

Try that and let me know..

Expert:  Jay replied 1 month ago.

I Will be back in 20 mins..

Customer: replied 1 month ago.
Ok
Expert:  Jay replied 1 month ago.

Back... Let me know how you made out..

Customer: replied 1 month ago.
That altima runs perfect with the maf from the sentra
Expert:  Jay replied 1 month ago.

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..

Customer: replied 1 month ago.
How can I test that
Expert:  Jay replied 1 month ago.

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..

Customer: replied 1 month ago.
Okay I can drop the exhaust
Expert:  Jay replied 1 month ago.

ok

Customer: replied 1 month ago.
The cat is the one with the o2 sensor plugo in
Expert:  Jay replied 1 month ago.

Yes, it is also the Exhaust manifold

Customer: replied 1 month ago.
Ok it's off car won't go past 3000 rpms
Expert:  Jay replied 1 month ago.

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.

Customer: replied 1 month ago.
clogged fuel filter or weak fuel pump
Expert:  Jay replied 1 month ago.

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.

Customer: replied 1 month ago.
Thanks if that checks out to be good where do I go from there
Expert:  Jay replied 1 month ago.

If that passes, then a scanner would be needed to monitor the fuel trim to determine direction.

Customer: replied 1 month ago.
Ok I'm going to go rent a fuel pressure gague
Expert:  Jay replied 1 month ago.

ok..

Customer: replied 1 month ago.
Ok got the gauge where do I connect it
Expert:  Jay replied 1 month ago.

You need to put it in line with the fuel feed to the injector rail.

Customer: replied 1 month ago.
I did that and I was only getting 25 psi
Expert:  Jay replied 1 month ago.

25 psi is way to low. You should be getting 56 psi. So you need a Fuel pump assembly to resolve your issue.

Customer: replied 1 month ago.
Okay new fuel pump installed still won't go past 2000 rpm
Expert:  Jay replied 1 month ago.

Really! What is the fuel pressure testing at? Where did you buy the fuel pump?

Customer: replied 1 month ago.
Auto zone and fuel pressure is at 60 psi
Expert:  Jay replied 1 month ago.

Was it a complete assembly? or did you have to take yours apart to change it?

Customer: replied 1 month ago.
Complete
Expert:  Jay replied 1 month ago.

Do you happen to have a scanner that can monitor fuel trim?

Customer: replied 1 month ago.
I do not
Expert:  Jay replied 1 month ago.

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.

Customer: replied 1 month ago.
It won't drive at all now it gets up to 2000 rpms and starts to jeez violently back and forth
Expert:  Jay replied 1 month ago.

That is why I want to check fuel trim now..

Customer: replied 1 month ago.
Where can I get that scanner none of the part stores sell it
Expert:  Jay replied 1 month ago.

You need a Advanced level scanner to do that. Those scanners are normally around 500 or better. Some bluetooth models can do it.