Mechanics

MY STARTS ROUGH....

Nissan Sentra

I have a '04 sentra 1.8 S. 79,900 miles. I've only had one problem with it since I bought it new in '03 (cd player) but for the last couple of months it wants to take five to ten seconds of cranking to get it started after the motor is warm. When the motor is cold, it starts like a champ. I've talked to some mechanics in the area that said it's probably a fuel pump. My question is, could it be anything else (and cheaper) to look into first. I've had it on a machine, it shows no codes as far as anything being distressed.

Do I spend the $400-$550 to get a new pump installed or take it back to the dealer and have them check the fuel pressure and anything else it could be?

any info would be insanly appreciated
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Evilcut99
January 5, 2007.




Why go to the dealer?

Try this first-when the problem would happen: Turn the key to the on postion without cranking it. Wait 5 sec. &Amp; trun it back to the off position.

Do this procedure 4 times.

Now crank it, does it start right away?

I was told by a mechanic that the fuel pump is a dealer stock item only. And to check the fuel line pressure can only be checked by a dealer because the fitting is some goffy size or something. I've also read that the fuel filter could possibly be clogged, but I guess the filter is housed in the fuel pump? He also said to turn the key on and not crank it, ( like you suggested) that doesn't make much of a difference.

Would a fuel pressure regulator be part of the problem? Is there any other parts that would be part of the problem and not be 4-5 hundred bucks?

Tiny
Evilcut99
Jan 5, 2007.
I'm not sure of the other prospects on it.

You can try to find the problem by checking the vacuum of the fuel pressure regulator, if gas is coming up the tube instead of air, it may prove the diaphram of the regulator is cracked.

For what it matters, if you contact a local snap-on dealer
http://www.snapon.com
he can refer you to an independent garage that can work on them. The aftermarket works hard to keep up by necessity.

Another possiblity is a carbon build up that soaks the gas before it burns it, this should be done regardless of the symptom:

I would try what I call an air induction service.
I like to use castle hydroblast. You spray it into a vacuum line such as the brake booster line if nothing else is accessible. Full spray for 3 minutes, stall the engine with it or have somone kill it while your spraying. Let it set for a few hours then take for a short drive in low gear, revving the rpms to help break it up. First use Castle cleansrite to clean the throttle bore. Try to get the throttle plates scrubbed good with a brush, while your spraying. Use a rag to wipe the carbon out between brushngs. Seafoam is another good product, but smokes a lot.

IF you can't find Castle, here is my rep's email:
robw@castlepackspower.com

The air induction service sounds like a good idea anyway. I'll do that on sunday. Thanks for the info.

Tiny
Evilcut99
Jan 5, 2007.
Try the fuel pump relay-Why, most EFI uses the oil pressure sending unit to back the F/P relay if it goes bye-bye to keep the engine going. If its wired like this-all it takes is 4lbs to close the OPSU then the engine will fire up. Or the cold start valve not kicking in between that time.

Have the fuel pressure check to include the coolant temperature sensor.

Tiny
Rasmataz
Jan 6, 2007.
I also had this sort of problem, my car would start easly when warm, but sometimes even in the middle of the summer it wouldnt start easly. I took it to nissan under warrenty and they said my fuel pump was messed or something. So I got a new one under warrenty. Sentra seem to have a cheap fuel pump, and I have read that alot of sentra guys have had the same problem. So my best guess for what I have read is it is most likely your fuel pump

the reason someone said to turn it to start and leave it for a while then go to off and then back to start and ignition, is because when u put the key to start it lets gas into the engine and thus making it easier to start. But if your fuel pump is toast, then that wouldnt make a difference because its hardly pumping anything.

Goodluck.
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Tiny
_spec_v_
Jan 9, 2007.
A fuel pressure check will tell you something about the injectors, filter, pressure regulator, and pump.

Tiny
Rasmataz
Jan 9, 2007.
The reason for the key procedure was to see if the check valve in the pump was failing and allowing a bleed back. But after reading the post again, it runs good when cold thus my thoery is invalid.

Service Writers : roll:


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