AtlasXVIII

Im new at this but lets try. I bought a z28 96' 5.7 3 days ago. Im having little problems. I full the gas in the car and drove it for about 15 miles and it was a quarter from empty. The car inside smells like gas. went I get out the car I hear a high pitch coming out of the gas tank. The temperature in the car is insane such as the oower lol. The oil pressure drops and jump up like crazy. I talk with the family mecanic and he told me that maybe the O2 sensor is not working well. Like I was saying let me know secrets that this car haves. What problem this car haves? The car is spending gas as hell is this normal please let me know thanks!!!!

Injuneer

Fill it up again. Maybe the gas gauge is faulty. If you used more than 1 gallon to drive 15 miles, and that 15 miles didn't consist of 60 1/4-mile passes, you have a problem. 1/4 tank left, with the known screwy calibration of the stock gauge would indicate you used 12 gallons driving 15 miles. How could you possibly think that might be normal? There would be liquid fuel pouring out of your exhaust.

Hard to understand how you didn't notice all these problems BEFORE you bought it.

AtlasXVIII

it actually smells like fuel went Im driving the car. What can I do to fix that?

AtlasXVIII

should I run Premium fuel or normal ? Thanks

Injuneer

To make full power, the engine needs premium. You can run regular grade, but you will experience a small loss of power.

But it makes no sense to worry about which grade of fuel to use, when there is a serious and dangerous condition. Did you check for a fuel leak? You can attach a fuel pressure gauge to the Schrader valve on the fuel rail, behind the passenger side of the engine, and check the fuel pressure. Turn the key to "run". The fuel pump will prime for two seconds, then shut off. The pressure at shutoff should be at least 40psi, and the fuel pressure should not drop rapidly.... it should hold, or drop very slowly. Rapid drop in fuel pressure can be:

-leaking fuel lines
-leaking check valve in the fuel pump
-leaking injectors
-leaking fuel pressure regulator

With the gauge still attached, engine off, pull the vacuum compensation line off the fuel pressure regulator. Check for wet fuel in the line. That would confirm a leak in the fuel pressure regulator, and that fuel would be pouring into the intake manifold, causing poor fuel mileage. It will also run past the piston rings, wash down the cylinder walls and dilute the oil, potentially leading to destruction of the engine.

If no fuel in the vacuum compensation line, plug the line to prevent a vacuum leak, and start the engine without attaching it to the fuel pressure regulator. Pressure should be 43.5psi, although GM accepts anything between 41-47psi. Reattach the vacuum line, and the pressure should drop about 8psi below the "no vacuum" reading.

Here's the location of the components, courtesy of Shoebox:

http://shbox.com/1/fp_reg.jpg

If you are not familiar with doing this kind of work, find a mechanic who is.

AtlasXVIII

Now it shows check gadgets!

AtlasXVIII

41.3 PSI and drop slowly

AtlasXVIII

The mecanic came and checked my car out. It didn't fiend any gas leak. He said maybe the O2 sensor or the gasoline tank was having problems. The pressure is not dropping or it drops really really slow. Im really worried

AtlasXVIII

can't post pictures here. Web force close

AtlasXVIII

No fuel in the vacuum compensation line! I connect it back and unplug fuel pressure regulator and it only drops to 35 no 8 psi. The engine is only dropping a little bit of Oil in the floor. sometimes the oil PSI jumps to 70 and cruising is not in a same position. It goes up and down If I full throttle the oil pressure goes up and gas down. I think I have a problem with the gadgets. Gas is know Half of it 1/2

Injuneer

Seems we may have a problem with the English language here. I did not say the pressure should drop TO 8 psi.... I said it "should drop about 8psi below the "no vacuum" reading." What that means is if you measured 43psi without the vacuum line connected, when you reattach the vacuum line, the pressure should drop 8psi, or mathematically 43psi - 8psi = 35psi. This appears to be exactly what you got. ??????

I think you need to focus on one issue at a time. I still can't understand how you managed to buy a car with so many problems. It has oil dripping on the floor????

Oil pressure varies with RPM.... as RPM goes up, pressure goes up. At low RPM (idle) pressure will be closer to 20psi. But you should never see 70psi IF THIS IS A STOCK ENGINE. Maximum pressure is set by the pressure relief spring in the pump, and that is 60psi.

That would be "check gauges".

Yes, if several of your gauges are jumping around irrationally, you may have a problem with the dash panel or with the ground for the dash. Did you refill the fuel tank to see how much fuel you actually used when you drove 15 miles? That will tell you if you are having a problem with your fuel gauge.

If you ask for help, then ignore the advice, you aren't likely to get much more help.

AtlasXVIII

I appreciate your help. I Follow all your steps and all sems to be normal. the only thing Im concern is the gas smell inside the car. If I start the car uphill it starts but then starts losing power and stalls. If I move the car without warming up the car it stalls. Ill check sensors Later. I hope is only the O2 sensor. Can you let me know your opinion in this problem? If it drops 8 psi it don't have fuel leak.? Sometimes in cold start the RPM stays at 1200 Thanks

Injuneer

So you did refill the tank with fuel to see if the gauge was correct, sitting at 1/4-tank? If you did, you failed to mention it. The objective there was to determine if you were experiencing problems with erratic gauge readings.

Since you are now only concerned about the gas smell in the car, and you feel your pressure does not drop quickly, appears you do not have lines leaking, do not have a leaking fuel pressure regulator, and do not have leaking injectors.

That's about all I can think of. Next thing might be the EVAP canister being full of fuel due to overfilling the tank, or the vent lines from the tank to the canister being rotted away.

AtlasXVIII

thanks very much. Tommorrow Ill check car sensors too se whats happening! My mecanic was the mecanic of the last owner" only one" The car was V6 STD and Got a V8 auto 4 swap. Love the car soo far and it haves ZR1 2011 rims and it looks really good. I was reading the owner manual and I found that the Fuel gadgets are not good said by GM. Ill drive the car tommorrow for work. Maybe the O2 sensor is the only problem. thanks for your Help Ill let you know what is the problem.

AtlasXVIII

manifold sensor is disconnected.? how can I connect it back??http://shbox.com/1/map.jpg the PVC PCC is disconnected