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-   -   fuel smell info (https://www.zdriver.com/forums/300zx-z32-performance-technical-47/fuel-smell-info-9391/)

jaffi 05-30-2004 05:03 PM

fuel smell info
 
I had a little problem with a gasoline smell eminating from under my hood. Since I've seen a lot of posts for this problem, I figured I should help out. Mine was a fuel pressure regulator that's located right above sparkey #6 ( at least I think it's 6). The part costs about $70 and is really easy to diy. Anyway, later.

outkast19 06-20-2004 08:56 PM

Fuel Reg
 
my car smells like gas to, did yours get rotten GAS MILEGE?

jaffi 06-21-2004 09:36 AM

My mileage was like 250 miles per fill up. Not great, but not that bad. Another thing to look at is your hose clamps attached to your fuel pressure regulators. They are on both sides, right above the # 5 and 6 cylinders.

outkast19 06-21-2004 10:01 PM

wheres my gas going?
 

Originally Posted by jaffi
My mileage was like 250 miles per fill up. Not great, but not that bad. Another thing to look at is your hose clamps attached to your fuel pressure regulators. They are on both sides, right above the # 5 and 6 cylinders.

im no were close to 200 miles per tank, something is definitley wrong

jaffi 06-23-2004 08:04 AM

YEAH, THAT AINT TOO GOOD. oH, I GAVE SOME BAD INFO. THE FUEL THINGY ABOVE CYLINDER #5 IS A FUEL DAMPNER. ANYWAY, JUST POP THE HOOD AFTER YOU START THE CAR. DO THIS WHEN THE ENGINE IS COLD, CAUSE THE HEAT OF THE ENGINE MAKES GAS EVAPORATE VERY QUICKLY AND IT MAKES IT HARDER TO FIND. WITH THE HOOD OPEN, JUST FOLLOW YOUR NOSE. MINE WAS REALLY OBVIOUS. ALSO TAKE A LOOK AT YOUR FUEL FILTER AND SEE IF THERE ARE ANY LEAKS THERE. ONCE YOU FIND IT, IT'S CAKE FROM THERE.

CanyonCarver 06-23-2004 08:35 AM


Originally Posted by outkast19
im no were close to 200 miles per tank, something is definitley wrong

I just got 277 miles on 12 gallons. Or 23 mpg.

91zxtt 06-24-2004 02:15 PM

Not even 200 miles on 1 tank of gas?!? That's awful. I can get to about 300 miles on a tank. Even if you ran that thing at WOT non stop you'd get better mileage than that. You have a serious problem, and it's more than a fuel leak. Does that thing pass smog?

outkast19 06-29-2004 01:36 AM

sucky milege
 
well check it out, i just bought this car, and they took it to emissions right before i drove it off the lot, im guessing it passed if they gave it to me when it got back, it turned out that all 6 spark plugs were shot, so i replaced them and then the milege improved, but im still no where near descent milege. i mean i just toped up the car, and after only 40 miles into it, its already down a quarter of a tank, and i have no idea were to start looking for the correct fix for this problem, can any one help me out?

emo236 06-29-2004 07:50 AM

On my old TT, I replaced all the fuel components. Its a good way to make sure you don't have any fuel leaks and most Z's need it anyway being that most fuel lines are hard and will crack soon. For now, take a screw driver and tighten down all the clamps from the fuel filter area to the fuel rails. Just follow you're fuel lines and start tightening. You either have a major fuel leak somewhere or some other problem. Do you blow black smoke out of the exhaust? a lot?

91zxtt 06-29-2004 12:00 PM

I'll get to 80-90 miles by the time I use 1/4 tank. Try changing your fuel filter and air filter. Run an ECU diagnostic and see if it has stored an error code. Maybe your O2 sensors are on their way out. You could try a fuel injector cleaner. Many people say you shouldn't use a fuel additive, but I have many times and have had no problems. I use Red-Line fuel injector cleaner.

outkast19 06-29-2004 09:18 PM


Originally Posted by 91zxtt
I'll get to 80-90 miles by the time I use 1/4 tank. Try changing your fuel filter and air filter. Run an ECU diagnostic and see if it has stored an error code. Maybe your O2 sensors are on their way out. You could try a fuel injector cleaner. Many people say you shouldn't use a fuel additive, but I have many times and have had no problems. I use Red-Line fuel injector cleaner.

how do i get my car in to diagnostic mode? i dont see a port any were like my 90 toyota had

outkast19 06-29-2004 10:03 PM

smelly
 

Originally Posted by outkast19
how do i get my car in to diagnostic mode? i dont see a port any were like my 90 toyota had

my car is giving me a code 55 which means no malfunctions, and ive been adding lucas fuel cleaner, my aif filters are clean, and the gas smell is eminating from under the car, not the engine. so im guessing i have some cracked and rotted lines, is there anything down there that is known to cause this problem?

emo236 06-30-2004 07:43 AM

Nothing I've heard down there, but try following your fuel lines from your fuel tank/pump to your fuel filter. maybe one is cracked. Or check your tank for cracks (unusual, but possible).

91zxtt 06-30-2004 11:31 AM

Yea, I bet that's the culprit. There's really not much else down there. All of your fuel hoses remain up and around the plenum.

jaffi 06-30-2004 10:17 PM

I think I've got your problem figured out. Maybe it's your fuel guage. I said I was getting close to 250 miles. Well, I checked that by counting gallons at fill up instead of looking at my guage and I ended up finding that I was getting more like 325 miles per fill up. For example, lets say I fill up after 240 miles and put in 12 gallons. I would then divide 240 by 12 and get 20. This is the avg mpg. I then multiply 20 times 7 ( the remaining capacity of the fuel tank) and get 140. Then just add 140 to 240 and that would be 380 per tank. When I did it I got an avg. of 17.5 mpg which is actually pretty good. Give it a try before you go thinking your car is screwed.

CanyonCarver 07-01-2004 05:38 AM


Originally Posted by jaffi
For example, lets say I fill up after 240 miles and put in 12 gallons. I would then divide 240 by 12 and get 20. This is the avg mpg. I then multiply 20 times 7 ( the remaining capacity of the fuel tank) and get 140. Then just add 140 to 240 and that would be 380 per tank. When I did it I got an avg. of 17.5 mpg which is actually pretty good. Give it a try before you go thinking your car is screwed.

It's not that complicated of a calculation. The key is to fill it up the same each time. Use the same pump at the same station each time.

Fill your tank and reset trip odo.
Drive a while. It doesn't have to be for a whole tank, but the more miles you drive on the tank of gas, the better the average will be based on the type of driving you do. Fill your tank again.

Now the math:

On my mpg above, I drove 277.4 miles and put in 12.1 gallons.
277.4/12.1= 22.92 mpg.

I just put new mufflers on my car last weekend, so I'm checking the mileage again to see if there's an improvement from the reduced back pressure. K&N is going on this weekend.

91zxtt 07-01-2004 11:01 AM

17.5 MPG on an N/A is pretty low. I get better than that in my TT. Either you have a problem, or you're at WOT all the time.

outkast19 07-01-2004 08:08 PM

bad milege
 

Originally Posted by jaffi
I think I've got your problem figured out. Maybe it's your fuel guage. I said I was getting close to 250 miles. Well, I checked that by counting gallons at fill up instead of looking at my guage and I ended up finding that I was getting more like 325 miles per fill up. For example, lets say I fill up after 240 miles and put in 12 gallons. I would then divide 240 by 12 and get 20. This is the avg mpg. I then multiply 20 times 7 ( the remaining capacity of the fuel tank) and get 140. Then just add 140 to 240 and that would be 380 per tank. When I did it I got an avg. of 17.5 mpg which is actually pretty good. Give it a try before you go thinking your car is screwed.

well my car has a strong fuel smell when it runs, some times it has got to the point were i couldnt breathe in the car.

CanyonCarver 07-02-2004 05:45 AM


Originally Posted by outkast19
well my car has a strong fuel smell when it runs, some times it has got to the point were i couldnt breathe in the car.

Is the smell actually fuel or maybe exhaust fumes. You might trying checking you shifter boot for cracks and any other places on the firewall where wires pass thru.

91zxtt 07-02-2004 09:06 AM

If it gets to the point where you have a hard time breathing, you shouldn't be driving the car. It'd be a shame to see the thing go up in flames. Put the thing up on Jack stands and roll under it with a creeper. it sounds like it should be pretty easy to find. Maybe even have the car running when you do this.

outkast19 07-03-2004 02:18 PM

bad cats?
 

Originally Posted by 91zxtt
If it gets to the point where you have a hard time breathing, you shouldn't be driving the car. It'd be a shame to see the thing go up in flames. Put the thing up on Jack stands and roll under it with a creeper. it sounds like it should be pretty easy to find. Maybe even have the car running when you do this.

i know its not my fuel gage, cuz it cost me almsot 30 bucks to fill back up, a friend at work told me that my cats could be pluged up, im going to have them checked today, he said when they get plugged they let out a lot of heat which my car is doing, and waste a lot of fuel

outkast19 07-03-2004 02:29 PM

Malo Gatos?
 

Originally Posted by jaffi
I think I've got your problem figured out. Maybe it's your fuel guage. I said I was getting close to 250 miles. Well, I checked that by counting gallons at fill up instead of looking at my guage and I ended up finding that I was getting more like 325 miles per fill up. For example, lets say I fill up after 240 miles and put in 12 gallons. I would then divide 240 by 12 and get 20. This is the avg mpg. I then multiply 20 times 7 ( the remaining capacity of the fuel tank) and get 140. Then just add 140 to 240 and that would be 380 per tank. When I did it I got an avg. of 17.5 mpg which is actually pretty good. Give it a try before you go thinking your car is screwed.

i know its not my fuel gage, cuz it cost me almsot 30 bucks to fill back up, a friend at work told me that my cats could be pluged up, im going to have them checked today, he said when they get plugged they let out a lot of heat which my car is doing, and waste a lot of fuel

91zxtt 07-06-2004 12:54 PM

It could be the cats, but the next question would be....what caused the cats to go bad? You could have a rich fuel mixture condition. Maybe O2 sensors, but the ECU would have detected that. Fact is, you still get the fuel smell. Your cats could be a problem, but you most likely have another problem as well.

outkast19 07-06-2004 08:48 PM

???
 

Originally Posted by 91zxtt
It could be the cats, but the next question would be....what caused the cats to go bad? You could have a rich fuel mixture condition. Maybe O2 sensors, but the ECU would have detected that. Fact is, you still get the fuel smell. Your cats could be a problem, but you most likely have another problem as well.

what do you think my best bet, keeping in mind that im a budget

CanyonCarver 07-07-2004 05:35 AM


Originally Posted by outkast19
what do you think my best bet, keeping in mind that im a budget

You can test your cats for clogging by feeling the amount of exhaust coming out of the tailpipes and comparing that "feel" to another vehicle with same size motor. If your cats are clogged there will be a substantial difference.

You can check whether they're functioning properly with a digital / infared thermometer. After driving the car around for a few minutes the temperature of the cats should be around 400 degrees. Most of the places that I go to for a smog check have one of these thermometers to check the cats.

A number of performance car guys that I know will take their cats off and hammer a bar or pipe thru them (down thru the exhaust pipe) to open them up and reduce back pressure. They still seem to pass the smog checks with cats like that.

The ultimate test is to remove them and drive it around. Again, if the cats are the problem, you'll notice a substantial difference in how it runs.

Cats do go bad. At 10 - 12 years old, if you know that they're the original ones, I'd replace them, or remove them depending on where you live. Like 91zxtt said, if you're not getting any CEL's, I'd focus on this first.


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