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Mike V.
Mike V., Nissan Technician
Category: Nissan
Satisfied Customers: 23845
Experience:  Nissan factory trained and Certified Subaru Technician.
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Sentra: i have a 2004 nissan sentra 1.8 litre. the car will

Customer Question

i have a 2004 nissan sentra 1.8 litre. the car will start up and stall out right away and then it wont start back up. i have changed the fuel pump the cam sensor and crank sensor also checked all fuses and relays and nothing has changed. i did a spark test on it and notice when you first turn it over it gets spark but then it seems to lose its spark. also the first time you turn the car over the fuel pump kicks on but then when you try it again it doesnt seem like the fuel pump is coming on.
Submitted: 1 year ago.
Category: Nissan
Expert:  Mike V. replied 1 year ago.
Hi there,Can you please try unplugging the mass air flow sensor and start the car.See if it will idle on it's own and let me know.Thanks.
Customer: replied 1 year ago.
no change it does the same thing
Expert:  Mike V. replied 1 year ago.
Do you know if the car is losing injector pulse as well? Meaning can you check it with a noid light and see if it loses the injectors at the same time it loses spark?Do you by chance have a scan tool that can see the live data?
Customer: replied 1 year ago.
i can check real quick to see if it loses injector pulse and i have a centec scanner its suppose to do live data but im not sure how well it works
Expert:  Mike V. replied 1 year ago.
Ok, if possible I would like to know if you can see the engine speed/rpms on it.If you have a noid light that would be great as well.
Customer: replied 1 year ago.
i hooked up the noid light and it seems like the injector pulse is not consistent just like the spark is not consistent
Expert:  Mike V. replied 1 year ago.
Ok, on the cam and crank sensors, did you use aftermarket or Nissan factory parts?
Customer: replied 1 year ago.
i got the intermotor sensors from advanced auto
Expert:  Mike V. replied 1 year ago.
Ok, you might want to try dealer parts. If the computer loses the signal from either of these senors, then it won't produce spark or injector pulse. Since you are losing both it makes me suspicious. This is part of the reason I was wondering if you can see the engine rpms or not. Since the cam sensor is what is used to produce rpms, which will also keep the fuel pump relay grounded it seems like it's losing the signal, or there is a possible issue with the computer itself. It's tough to know which is the problem without any codes though.
Customer: replied 1 year ago.
ok i will go get dealer parts and see if it works
Expert:  Mike V. replied 1 year ago.
Thanks, ***** ***** think its the best place to start because it has spark and pulse at first and then loses it.
Customer: replied 1 year ago.
I changed out the sensor and it's still doing the same thing.
Expert:  Mike V. replied 1 year ago.
Which sensor did you replace?Does this car have any type of aftermarket security or remote starter on it?
Customer: replied 1 year ago.
I replaced both and no after market security or remote start.
Expert:  Mike V. replied 1 year ago.
Ok, to be clear, as you are cranking the engine you actually see the noid light stop pulsing?Does the car have the factory security system in it? Chip key?
Customer: replied 1 year ago.
Could the cat possibly be clogged
Expert:  Mike V. replied 1 year ago.
A plugged converter could prevent the car from starting, but it's not going to stop fuel and spark which is what you are saying is happening. IF you want to check for a plugged cat, remove the top O2 sensor from the exhaust manifold and try to start the car. However, if this works, then the car clearly has fuel and spark.
Customer: replied 1 year ago.
As I am turning over the noid light will flash every couple seconds and then there will be a pause and then it will flash like it skipped a couple rotations and it will keep going like that. No the car doesn't have a factory alarm or a chip key.
Customer: replied 1 year ago.
And the spark is the same way. It doesn't completely lose it there is just a big gap between Sparks after the first couple rotations.
Expert:  Mike V. replied 1 year ago.
I think you should check the compression at this point. If the car isn't turning over properly, out of time or if the battery is weak you might get this issue. It has to crank at least 250 rpms for the ignition to kick on.
Customer: replied 1 year ago.
Could there possibly be a problem with the ignition switch. I will check the compression when I get home.
Expert:  Mike V. replied 1 year ago.
I would not consider the switch to be the problem because it appears to be getting what is needed through the switch because even though it's bad, there is spark and fuel. Trying to figure out what in the world would cause it to taper off like that is the trick. Check the negative battery cable attachment points as well. The ecm is getting signals from both the cam and crank sensors if it's giving you spark and fuel, it fading off may be battery or ground related.
Customer: replied 1 year ago.
Compression is within 2-3 psi on all 4 cylinders. With the plugs out on my scanner it is reading 175 rpm while turning the motor over. I have looked at the grounds and they looked ok but I will check them all again.
Expert:  Mike V. replied 1 year ago.
Ok, we have to get the rpms up to 250 or the car won't start. Try jumping the car, 175 is just to low. I am assuming compression was good, at least 125 or better.
Customer: replied 1 year ago.
Yea compression was good. I will hook the jump pack up to it and see if I can get it to run.
Expert:  Mike V. replied 1 year ago.
Ok, it has to be 250 rpms to get the engine to fire and run properly.
Customer: replied 1 year ago.
I hooked up the jump pack and I'm getting 250-262 rpm while cranking and it will spike up more when it tries to fire.
Expert:  Mike V. replied 1 year ago.
Try holding the gas pedal 3/4 of the way to the floor and see if it will start or not.Also, if you spray some carb cleaner into the throttle will it run off that longer?
Customer: replied 1 year ago.
Holding the gas pedal 1/2-3/4 of the way done doesn't help. And carb cleaner doesn't help. I can smell fuel when I am holding the pedal down.
Expert:  Mike V. replied 1 year ago.
Are the plugs saturated in gas?Did the car have any history with using coolant?
Customer: replied 1 year ago.
No
Expert:  Mike V. replied 1 year ago.
What was the actual compression?
Customer: replied 1 year ago.
118-121 but my compression tool is missing the o ring so it reads a little lower
Expert:  Mike V. replied 1 year ago.
Ok, I am showing 168 psi to be the min allowable compression. If possible could you put about a capful of oil down each cylinder and retest with all the plugs out and your battery pack on the car so it's cranking the highest rpms we can get.Thanks.