2004 nissan sentra bad camshaft sensor, replaced with a new one and now car won't start. Also replaced crankshaft position sensor and sitll only runs (like ****) when I put the old bad camshaft sensor back in.

front of engine, left side, below the camshaft sensor, get a repair manual , HAYNES it will help you be a mechanic , & tell you what all the sensors do, are located, & so on .....................

No that would not affect temperature in any significant way. the engine in most cases just won't run or will be hard starting.

it is On the back side of the block(below the intake manifold). on 1.8 engine. nissan sentra.

The crankshaft position sensor (POS) is located on the oil pan facing the gear teeth (cogs) of the signal plate. It detects the fluctuation of the engine revolution.
After replacement, ECM reprogramming is required.
This vehicle may be subject to voluntary recall, CAMPAIGN I.D. # R0606, that involves the crankshaft position sensor:

Quote: Nissan has determined that on some 2003 - 2004 Altima and Sentra vehicles with the 2.5 liter engine the operation of the crank angle sensor is significantly affected by variations in temperature that occur due to the unique location of the sensor in the engine. Under certain driving conditions, these variations in temperature can be large enough to cause a brief interruption in the signal output from the sensor. If the interruption in the signal from the sensor is so brief that the Electronic Control Module (ECM) logic does not have time to diagnose the condition, the engine may stop running without warning while the vehicle is driven at low speed.

May need to take it to a car electronics specialist, it may be something broken that only will come up when doing a diagnostic test

Go to dealership they will give a diagram to locate every single one. I replace them on my daughter car. I believe there were three sensors. I exactly know what you are talking about. I had a hard time locating the back one right above the drive shaft on driver side.

In the kit there are two sensor that look identical. The one for the crankshaft has a white paint mark on it near the bolt hole. Make sure that it is in the right location.

try replacing the crankshaft and camshaft sensers, my 2004 sentra spec v had the same problem.It cost me $122 for both the sensers and can be done in 20mins

I am not sure where in a Sentra, but in a Quest 1993-02, it is in the distributor (integral). Common problem with Quest is that brown dust covers optical sensor under slotted wheel under rotor. If dust, the bearing is failing and you need new distributor. Clean optical sensor and see if it starts and runs. Get dist. on ebay.

report back on progress.

check the fuel pump first.after that check the fuel filter. probably it is clogged.these parts are loacted in your fuel tank floater.remove the back seat.remove the screws.your car is young so the crankshaft position sensor must be working properly.