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Jake
Jake, Nissan Technician
Category: Nissan
Satisfied Customers: 3788
Experience:  Experienced collision repair technician, Pulaski Tech graduate and DSM hobbyist.
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I replaced the throttle body ono a 2005 altima did an idle

Customer Question

I replaced the throttle body ono a 2005 altima did an idle relearn and after the car will not start it is not getting rpm signal
Submitted: 6 months ago.
Category: Nissan
Expert:  Jake replied 6 months ago.

you listed this as a 99 altima? is it a 99 or an 05?

Expert:  Jake replied 6 months ago.

The 99 would have a distributor and a cable driven throttle, so since you performed an idle relearn lets go with the fact its likely an 05

Expert:  Jake replied 6 months ago.

if so the RPM signal will come from the crank sensor.

Customer: replied 6 months ago.
Sorry working on 2 at once it's a 200t
Customer: replied 6 months ago.
2005
Expert:  Jake replied 6 months ago.

are you getting any codes at all? are you getting spark?

have you tried unplugging the crank sensor and starting the car in safe mode?

Customer: replied 6 months ago.
I have spark yes I have tried to start with it unplugged still no start
Expert:  Jake replied 6 months ago.

what did the car come in the shop for?

Customer: replied 6 months ago.
It had a bounceing idle Rev up and down
Expert:  Jake replied 6 months ago.

and you replaced the throttle assembly, did the relearn, and now the engine cranks but won't start.

you have no RPM signal yet you have spark?

all this is correct?

Customer: replied 6 months ago.
Expert:  Jake replied 6 months ago.

when you turn the key to ON position and leave it, you don't get anything peculiar like a condensor fan running, the security light on solid, or a service engine light right?

Customer: replied 6 months ago.
No everything seems normal
Expert:  Jake replied 6 months ago.

try starting the car while depressing the gas pedal for me.

Customer: replied 6 months ago.
I have done that
Customer: replied 6 months ago.
Just cranks
Expert:  Jake replied 6 months ago.

have you tried starting fluid?

Expert:  Jake replied 6 months ago.

because nothing is really adding up to be honest

Customer: replied 6 months ago.
Yea I did it started one time but had to crank the throttle
Expert:  Jake replied 6 months ago.

your saying the car will not start with the crank sensor unplugged or plugged in. Your saying you verified it has spark and replaced the crank sensor already.

Since you replaced the throttle I was hoping the closed position set was not met and it was not getting enough air, but you already attempted that as well.

you said the secuirty light was not on solid, so it should have injector pulse. Since it did start the one time though with started fluid can you verify injector pulse for me?

Customer: replied 6 months ago.
Ok doing know
Customer: replied 6 months ago.
Yep have pulse
Expert:  Jake replied 6 months ago.

The pump must not be running then because it can't see engine speed

Customer: replied 6 months ago.
That is my assumeption
Expert:  Jake replied 6 months ago.

did you scope the crank sensor by chance just to make sure its seeing the reference?

or make sure there is voltage to the sensor and a ground also?

Customer: replied 6 months ago.
Check for voltage and ground did not scope
Expert:  Jake replied 6 months ago.

Thats so odd for a car that came in for a throttle issue to now have no RPM signal.

all i can think of at this point from your descirption and symptoms over the net is that the reference signal back to the ECM is not getting there.

Expert:  Jake replied 6 months ago.

hence no RPM signal and the fuel pump not running after priming.

Expert:  Jake replied 6 months ago.

and seeing that its a 2.5 altima with spark and injector pulse we KNOW the cam sensor is functioning fine

Customer: replied 6 months ago.
Agree
Expert:  Jake replied 6 months ago.

so until you check continuity from the crank sensor reference wire to the ECM, and verify a reference signal. We have to assume it's not getting there since your scanner shows no signal.

Which means start at the crank sensor and connector inspection or proceed with above mentioned steps.

Wish i had an easier nugget of advice on this one.