# 94 sentra no start but will crank ...please help



## joefrank1982 (Dec 29, 2014)

Hey guys I have 94 sentra 1.6 that wont start. I checked the fuel pump fuse and relay then I checked the pressure on the fuel line (45 psi). I then check for spark with a spark plug tester and the light came on. I then cleaned and tested the crank shaft position sensor CSPS in the distributor assembly which had a pretty nasty oil saturation. The voltage on the first pin of the CSPS I got what the manual said ( 0-5 volts) but the 2nd pin gave me 0-3 volts even though the manual says otherwise I never got 5....maybe I didnt back pin well enough. Now Im starting to think its the fuel injectors....Im lost and tired and any help would be greatly appreciated....

ps could I get pressure from the fuel tank and pump not be working... i can never hear the pump but I had pressure.


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## b13er (Apr 7, 2010)

SPARK:
Not sure what kind of spark tester you're using, but maybe you should use an actual spark plug so you can see how big the spark is. Either buy a normal spark tester at Autozone, or just hold the body of a spare spark plug to a good ground and have someone else try and start the car. JUST DON'T SHOCK YOURSELF.

AIR:
Car's need air, make sure that air filter isn't clogged. Heck take it out and try and start the car. Just don't suck up any rags or bolts.

FUEL:
No way are you going to get 45 psi from gas pressure in a fuel tank. But be sure to test the fuel pressure after the fuel pressure regulator to make sure the problem isn't the FPR. It should be 43.4 PSI after the regulator.

After trying to start the car, you should be able to remove a spark plug and smell all the unburnt fuel.

Injector test: Have someone try and start the car and put a flathead screwdriver up to each fuel injector and put your ear on the handle. You should hear the fuel injector clicking.

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The car can run without a MAF sensor thanks to the "Fail Safe System(EF-EC 218 of the 94 sentra FSM)" , but sometimes when they break they stop your car from working. Try unplugging it then try and start the car. Next plug it back in and then try unplugging your TPS and see if the car starts. Also just for reference the engine coolant temp sensor can be broke and the fail safe system compensates. It's hard to get a multimeter in there to test it, but it wouldn't stop your car from starting anyhow.

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On a 90 - 94 sentra the camshaft position sensor is built in to the distributor and so the only way to replace it is with a new distributor.

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On this forum we have seen way too many ga16de's that would not start until the owner bought a new distributor. As of right now it's the only piece of equipment that can't truly be tested. Even the FSM says to swap it out for a good known distributor in order to diagnose the problem. It should be the last thing you try. If you google "sentra fsm" and download it, go to the very end and it shows you how to test almost every piece of equipment under the hood of your car with a multimeter. When all else fails, distributor time.


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## smj999smj (Jan 1, 2006)

"_FUEL:
No way are you going to get 45 psi from gas pressure in a fuel tank. But be sure to test the fuel pressure after the fuel pressure regulator to make sure the problem isn't the FPR. It should be 43.4 PSI after the regulator_"

This in incorrect. You never check fuel pressure _after_ the fuel pressure regulator. You check fuel pressure between the fuel pump and the fuel injector fail (before the fuel pressure regulator), preferably after the fuel filter. Static fuel pressure should be around 45 psi and you should also see about the same pressure with the engine running and the vacuum hose disconnected from the fuel pressure regulator. With the vacuum hose connected to the regulator and the engine running, you should see about 34-36 psi. You would not see any fuel pressure if the fuel pump was not working.

If there is oil inside the distributor, you should go ahead and replace the distributor assy. This is an indication that the internal oil seal that goes on the shaft has failed. Personally, I recommend genuine Nissan remans, but they are a lot more expensive than aftermarket and most don't want to spend the extra money, even though the quality is much better. Assuming you don't get a bad, new part, this would rule out the possibility of the distributor being the culprit, as well. 

What I don't understand is that you say you have fuel pressure and that when you tested for spark, the light of the spark tester came on, which would indicate that you are getting spark. If you are getting spark to the plugs, there is no reason to check the cam position sensor. What I would check is to make sure the plugs are not gas fouled and I would do a compression test of all four cylinders. Low or erratic or no compression would be an indicator of jumped timing, weak rings or fuel-washed cylinder walls, among several other possibilities. If you want to test the fuel injector circuits, best way is to use a noid light for Bosch-style injectors. This will go into one of the fuel injector harness connectors and will flash when the engine is cranking, indicating that the injector has power, the ground circuit is good and the ECM driver is working to pulse-ground the injector to "fire" it.

Another way to check for a fuel delivery issue is to spray carb cleaner into the engine and attempt to start it. If the ignition system and compression is good, the engine should fire on the carb cleaner, indicating the engine is not getting fuel. Since you already verified sufficient fuel pressure, the engine not firing on the carb cleaner would be an indication that fuel is not getting past the injectors, possibly because they are clogged, but more likely that they are not being "fired" by the ECM. Here's where that noid light comes in handy.


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## b13er (Apr 7, 2010)

I got that advice from someone on here, but I see you are indeed correct:


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## joefrank1982 (Dec 29, 2014)

I thought the spark seemed weak so I took the battery in to get tested and it was bad...Took home the new one and it started right up. Lesson learned check the basics first.

Thanks for all your help guys.


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## joefrank1982 (Dec 29, 2014)

UPDATE -Turns out the battery wasn't it. I drove the car to work one night made it half a block and it died...pushed it back home and swapped out a junkyard distributor assembly/ crank shaft position sensor and Ive been driving it ever since....THANKS


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## Stevo92 (Dec 3, 2015)

b13er said:


> On this forum we have seen way too many ga16de's that would not start until the owner bought a new distributor. As of right now it's the only piece of equipment that can't truly be tested. Even the FSM says to swap it out for a good known distributor in order to diagnose the problem. It should be the last thing you try. If you google "sentra fsm" and download it, go to the very end and it shows you how to test almost every piece of equipment under the hood of your car with a multimeter. When all else fails, distributor time.


I have just been able to start my GA14DS after replacing the distributor - very common failure apparently. Thanks Man!


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