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Discussion Starter #1
Hi guys,

Im new to the forum and to Nissan engines. I live in sweden and i don´t have that much experiense with Nissan engines at all. :)
I own a 1988 Nissan Sunny (sentra) 1.6 SLX and i´ve been having some problems getting it to run.
The engine has been running very rough and erratic ever since i bought it and it´s hesitating when i try to give it more gas.

Last week it just died (in the middle of a runabout with heavy traffic i might ad). I just thought it was out of gas since the gas meter don´t always work.

I filled it up with about 5 liters of gasoline but it wont start.

When i open the air filter cap and pour some gas directly in the throttle body it runs for a few seconds then it dies again.

The strange thing is that i´ve been following the fuel line all the way to after the fuel filter and there is fuel running to that point when i turn the key.

Can any of you give me some input on this?

I´ve checked all the fuses btw.
 

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NF Mod/Nissan Master Tech
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First, you need to install a fuel pressure gauge and confirm proper fuel pressure. If the fuel pressure was ok, then I would confirm there is 12v power at the fuel injectors with the key "on." If there is no power, then the circuit must be checked to find out why not. If there is power, the ground side circuit will need to checked for continuity between the injector and the ECM. The circuit should also be checked for no continuity to ground.
 

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Discussion Starter #3
Thanks for your reply.

The gas is flowing to the injector so i unscrewed the fuel return hose to check and when i turned the starter on it was squirting out gas like hell, so i dont think the issue is with the fuel pressure.

Can it be a stuck valve of some sort? Should i take the whole injector appart and clean it perhaps?

Best regards
Nicklas
 

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Sup Mod keeping the peace
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By unscrewing the fuel return hose is not the proper way to test fuel pressure. The fuel pressure regulator may be bad and it may just be diverting all the fuel back to the tank; the result is no pressure at the fuel injectors.

The proper connection for testing is to tee in the gauge between the fuel filter and the fuel rail. The pressure should be somewhere between 36 - 43 psi at idle.
 

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Discussion Starter #5
By unscrewing the fuel return hose is not the proper way to test fuel pressure. The fuel pressure regulator may be bad and it may just be diverting all the fuel back to the tank; the result is no pressure at the fuel injectors.

The proper connection for testing is to tee in the gauge between the fuel filter and the fuel rail. The pressure should be somewhere between 36 - 43 psi at idle.
Thank you,
The problem is that the engine won´t start at all so i wont be able to check the fuel pressure. The engine only starts when i pour some gas directly in the throttle body.

I was doing the other part to ensure that there was fuel running all the way.

Does anyone of you have a repair manual for this engine?
 

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Did you check all of your vacuum lines? Specifically the line that goes to the fuel regulator. I'm going out on a limb here, but I agree with rogoman about the fuel regulator. I think the easy way to test a regulator is to bypass it. Your engine will run like crap but it should start. If it does, you know what the problem is. Remember that this is just a test, don't drive it like that because the fuel rail will be getting full pressure from the fuel pump. At the least, it will run rich as he--. At the worst, you'll blow other stuff out by letting it run too long or by driving it.
 

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NF Mod/Nissan Master Tech
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You don't need to start the engine to test fuel pressure. With the gauge installed, turn the key "on" and the fuel pump will prime the system and you can see what the pressure is.

I wouldn't take apart the fuel injectors. First, you must see if the fuel injectors have power to them and then you must see if the ECM is firing the fuel injectors. You can have all of the fuel pressure in the world, but if the fuel injector is not operating, there will be no fuel getting into the combustion chamber. Checking power is easy enough by using a 12v test light. A better way is to use a "noid" light, which plugs into the fuel injector harness. If the circuit has power and is being pulsed to ground by the ECM, the noid light will flash as you attempt to start the engine. You can do a similar check with a pulse meter. Without either one of those tools, the best you can do is check and confirm power to the injectors, then isolate and check the integrity of the injector ground circuit, then check the ECM grounds. Due to the age, I'd be surprised if you can find an online service manual. I have seen Nissan factory service manuals for say on Ebay for around $35 and they are worth every penny! You can also get a single vehicle subscription to ALLDATA that will have the same information as the service manual.
 

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Discussion Starter #8
I tested the fuel-pressure and got 3bars/~40psi wich it should be if i read the manual correctly.

i also messaured the cable to the injector, there was two pins and one of them had 12v in it without the ignition on.

I then found out how to read the error codes and after setting it to mode 3 i got error code 41, air temperature sensor. i then checked the sensor and one cable is off so im replacing that today. Could that be why the engine wont start? In my opinion it should but have a terribly wrong fuel/air mixture.
 
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