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Jay, Nissan Technician
Category: Nissan
Satisfied Customers: 20248
Experience:  20+yrs experience with Nissan & Infiniti Trained & Certified.Currently still working for Dealer
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1999 Nissan Maxima: with 89,000 miles..driven..ran fine..smooth

Customer Question

I just bought a 1999 Nissan Maxima with 89,000 miles. The guy I bought it off of said it hadn''t been driven in over a year. The battery was dead so I replaced it and it started right up and ran fine, very smooth. This was about three days ago. My wife drove the car back and forth to work and on her way home yesterday the service engine light came on with a P1491 code and at first didn''t run any different but after about ten miles or so it started running very rough and sputtering. When I got home and checked it out I it smelled like gas and when I started the car gas was pouring out of the exhaust. She had a half a tank of gas earlier and it was gone. Would the evac valve cause this? I thought it was just for vapors. What could cause something so severe. Right now it has another code that said random misfires and it will barely start.
Submitted: 9 years ago.
Category: Nissan
Expert:  Jay replied 9 years ago.

Hello and thank you for using

The first code you have P1491 is a evap code for the Vacuum Cut Valve ByPass Valve, See image. That could be giving you the gas smell if a Evap line is broken. I would inspect that plastic valve and have evap system checked. Vent control valves and evap canisters are some what common.I don't think gas was coming out of the exhaust, it may have been just condensation build up ( water ), that is common to drip from the tail pipe.graphic

The running ruff and misfire code. There was a common problem with Nissans ignition coils. If you have a ignition primary code, that would indicate that all coils should be replace. I certain misfire code, you may be able to get away with just the one coil. I would see if you can get the code, so you can look into the cylinder that is misfiring.

If you have any more questions about this, please feel free to ask. Thanks

Customer: replied 9 years ago.
Reply to FixUrNissan's Post: It was not water coming out of the tailpipe it was gas and lots of it. She had half tank and within an hour it was empty. When I checked it in the drive way there was a puddle of gas that took 15 minutes to evaporate and the neighbors were complaining. It actually ran out of gas in the driveway. The misfire was after all this started and I'm not talking about a miss I'm talking about the engine barely running if at all and forget about idling. I have checked all the hoses and they are in great shape, no cracked or weathering.
Expert:  Jay replied 9 years ago.
Well if there was gas all over the drive way, you have some kinda of fuel leak. There is no way that much gas can come out the tail pipe. I would have the fuel system checked for leaks, it could also be dangerous to drive if it is leaking gas. If you can not find where the gas is leaking I would tow the car to someone who can perform a fuel pressure test, to find the leak.
Customer: replied 9 years ago.
Reply to FixUrNissan's Post: This was not a leak I was watching it come out of the tailpipe with smoke and an occasional backfire. When it got this severe it would not run past 1,000 rpm's.

This evac goes from the tank to the intake with valves inbetween. Is there anyway the vacuum from the intake could suck gas out of the tank if a valve were defective? I know it's only supposed to suck out fumes but I've got a real problem and it's not a leaky fuel line, I've never seen or heard anything like this.
Expert:  Jay replied 9 years ago.

This does sound a bit strange. There is no way the Intake can suck the tank dry. The only other thought is maybe you have an injector or 2 stuck open, and is dumping fuel into the cylinder. I would remove the spark plugs and see if they are wet with fuel also. If they are, I would pull the fuel pump fuse and crank the car with the plugs out to try to dry out the cylinders.

Customer: replied 9 years ago.
Reply to FixUrNissan's Post: Ok I might have exagerated a little with drain the tank dry but it is sucking up gas and fouling on all cylinders (I used a test light to ground the plugs when I got it to run) It was only firing on two strong enough to keep the engine running and now it won't even start. Where is the evap canister purge control vacuum solenoid and the Canister purge volume control valve and the Canister purge control valve that the code is referring to? Also if it does have a stuck injector is that fixable or does it have to be replaced?
Expert:  Jay replied 9 years ago.

If you have a stuck open injector, then the injectors would need to be check to find out witch one of them is stuck open, by ohming each injector.

The Evap Canister is located in the drivers side rear. Here are some images for you.graphicgraphic

Customer: replied 9 years ago.
Which of the two evap parts in known to go bad first? And is this all there is to the evap system?
Expert:  Jay replied 9 years ago.
There quite a few hoses and componets to the evap system. The most common is probably the evap canister and vent control valve.
Customer: replied 9 years ago.
Reply to FixUrNissan's Post: One last thing, is there anything you can think of that would allow gas into the intake manifold thus uniformly flooding all cylinders with gas.

I just can't believe a sticky injector could do this just because there is so much gas and it is killing all the cylinders not just one or two.

It started all at once (two hours total time) with the engine all of a sudden running very bad to not idling and running very bad to backfiring and smoking to the engine dieseling when shut off to all this gas spewing from the tailpipe and the engine so flooded it will not run.
Expert:  Jay replied 9 years ago.
Well it is possible the Ecm ( the main computer ) failed. The computer controls injector pulse. If the computer just turned the injectors on , instead of pulsing the injectors on and off. Then I could under stand why all the cylinders loaded up with fuel.
Customer: replied 9 years ago.
Reply to FixUrNissan's Post: Wouldn't that produce a code?
Customer: replied 9 years ago.
Relist: I prefer a second opinion.
I would prefer a new Expert, Please.
Expert:  Jay replied 9 years ago.

If the computer failed, it may not produce a code.

I will opt out an let another expert give you there opinion. Thanks and hope everything works out for you.