i installed a used engine in my 2000 maxima 5sp and now it runs really rich but when i unplug the mass air it runs fine. the mass air is new and the car ran fine before i installed a new engine. any ideas???

ok here is what you people are missing. the car runs great with the (REF) cam sensor unplugged. it is not until the cam sensor is plugged back in that i get the problem. it can even be plugged in and not mounted to the block and it sill runs fine. i would leave it this way but it will not always start with the cam sensor unplugged. so i dont think it is Fuel injector, Exhaust gas leak, Incorrect fuel pressure and the mass air flow is brand new.

 

How do you know it''s running rich? What AFR is it at when idle, WOT & part throttle?

 

well it is blowing fuel out the tail pipe i know a bit about cars it is fuel.

UPDATE!!!!!!!!!

when i remove the front crank sensor it will run fine it just takes a while before it starts. i tested the crank sensor and it is at .56 ohm which is in spec. i have a spare tryed that one and it the same. i checked the wiring to the crank sensor and it is good. the crank sensor can be plugged in and just not mounted to the block and it will run. but as soon as i mount it the engine runs ruff and it dumps in fuel. i put a scan tool on and the timing is at 2 deg when it should be at 15. the rpms read 300 at the scan tool but the tach says 1000. thats all i got so far also new mass air

 

No AFR, no care.

 

whats AFR how do you check it

 

airfuel ratio, and you would use a wideband.

But if I were in your shoes, i would check the codes and replace whatever those codes tell you is wrong. Most likely a/some sensor(s)

 

codes are misfire and evap

 

Fix the misfire. (coil{s})

 

it doesnt need coils it runs fine when there is no crank sensor

 

Change the faulty crank sensor.

 

you need to read what i wrote the crank sensor is fine i tested it

 

Sensors can check out fine, and still may be faulty. It's happened
to me plenty of times.

Try cleaning the senor and its mounting spot.

 

did it. i have two sensors one is only a year old. and the car ran fine before i put the engine in.

 

wtf? WTF?
don't you think the misfire may be the problem?

uhh ok, i don't understand how the crank sensor can be the problem really.. it senses the position of the crank! unless your ignition system is faulty and doesn't know when to ignite
you check them plugs n ish?

 

there's actually 2 crank sensors one by the balancer pulley and one up top. Positive and i forgot the name of the other one.
Is your evap cannister full of fuel? check that too. It's supposed to only suck in vapors.
Did you get the harness from the old engine too? There's a bulletin on some of them braking around the driver's side by the rear rocker cover
also leaky injectors could make it run ritch or a faulty fuel pressure regulator or an airflow meter. or even an o2 sensor. Now you can narrow it down and figure out what of those parts you left on fromm the new engine.

 

POS and REF. It's not up top, it's near the tranny.

The one up top is the cam sensor (phase)

 

whats with some of these sigs? i got hell for showing a cute anime one with covered bouncing *****, and i see ppl shaking ***'s why dont they get *****ed at?

 

Possible causes of this problem are:

1. Front heated oxygen sensor
2. Fuel injector
3. Exhaust gas leak
4. Incorrect fuel pressure
5. Mass air flow sensor

Check the exhaust and intake for leaks. Then check the oxygen sensors for an open circuit or short. Check the fuel pressure regulator, pump and fuel pump circuit. The fuel injectors can be checked by removing them and checking for dripping from the injector. If you have a P0172 code the problem is with the right bank. If you have a P0175 code it's the left bank that should be tested. The injectors should make a clicking sound if they are operating correctly. This will require an automotive s***hoscope or other listening device.

Be careful when checking injectors. Fuel should not be allowed to get on engine and the engine should cold.

Proceed at your own discretion.

 

the car will run fine with the crank unpluged and the mass air is new so i dont think it is any of these