Fuel system not getting gas correctly - 1991 Buick Park Avenue

What are the indications of bad gasoline?
A:

QUICK ANSWER

The symptoms of bad gas involve a lean misfire, which creates a P0300 code in newer cars, engine detonation and pinging, sputtering and stalling. These occur because the bad gas fails to keep the fuel system clean and introduces contaminants that can clog fuel filters, fuel pumps and fuel injectors. In addition, bad gas can have an octane rating lower than advertised, leading to the aforementioned detonation and pinging.

FULL ANSWER

Receiving bad gas from a fueling station is more common than the industry admits. The only cure for fixing bad gas is to drain the fuel tank and fill it with fresh gasoline while cleaning the fuel system in the process. Bad gas can be caused by gasoline suppliers not mixing the required amount of additives in the fuel, causing them to be less effective in preventing deposits and causing fuel varnish to form in the fueling system. Sometimes the tanks, whether at the fueling stations tanks or in the vehicle's own fuel tanks, are contaminated with dirt, corrosion and water. Because no filtration system is absolutely perfect, even with the various filters and stringent EPA requirements in place, these contaminants end up inside the car and may damage it. Gasoline that is lower in octane often occurs because either the supplier or the fueling station intentionally sells regular fuel as higher octane, profiting over the difference in price.

Did you release the air in the system. You may have an air pocket stuck in the fuel line system. If it is fuel injected, be careful because the line pressure can be extremely high and if not released properly it can leak out under high pressure. Be sure you changed the fuel filter as well. Things can find there way into the lines when removing and installing things in line. Check that you have sufficient fuel pressure at the carb or fuel injection system. The system requires to be pressurized so that the injectors operate correctly,

P1450 EVAP Control System Fault, P1450 Unable To Bleed Up Fuel Tank Vacuum.
These are Emmision system faults, the can be as simple as the gas gap on the filler spout is not correct placed, or is missing. It can also indicate other issues with the fuel system from
gas tank to injection. Sometime replacing the gas gap with a correct new one solve the problem.

sound like problem with the EVAP SYSTEM.HAVE CHECK OUT. trick to pumping gas dont stick fuel spout all the way in hold it back a little then pump gas the gas vapors stored in fuel tank stopping you from pumping gas.hold spout back pump gas.

It would be really nice to know EXACTLY which code you are getting. However, since you mentioned gas cap, I will assume that you are getting Diagnostic Test Code (DTC) P0457.

First, you need to understand that DTCs (or fault codes) NEVER tell you what parts to replace. They only tell you which of the many circuits and systems monitored by your onboard computer network is malfunctioning. The circuit or system must then be properly diagnosed to determine the actual CAUSE of the failure. To do that, you need to follow the correct diagnostic procedure and you also need to know how the system is supposed to work, so you will know a malfunction when you see it.

Here is what is causing your confusion:
The standard definition for DTC P0457 is "Evaporative Emission System Leak Detected (fuel cap loose/off)"
Please note here that the part about the fuel cap is in parenthesis. The MAIN description is "Evaporative System Leak Detected." This fuel cap part is only because this code is very often caused by people not putting their fuel cap on correctly, forgetting to put their fuel cap on at all or losing it, or refueling their engine with the engine running. So, this part of the DTC description is NOT telling you to replace the gas cap. It is only telling you to check for a loose or missing gas cap for a possible cause because it is so common.
What the code REALLY MEANS is that there is a HUGE leak in your EVAP system.

Please also note that a fuel tank pressure (FTP) sensor that is not working correctly can also cause the computer to "think" that there is a huge leak when there is not...Hence, the need for proper diagnosis.

The operation of the FTP needs to be verified to make sure it is not "lying to the computer. All of the hoses, lines, tubes, charcoal canister, and other components of the EVAP system need to be inspected for cracks, tears, breaks, etc. that would cause a leak in the system.

If this is a sudden occurrence and nothing suspicious happened prior, you most likely lost either gas or spark to the engine. You need to check for both.

Do you hear the fuel pump in the gas tank buzz on for a couple of seconds when you turn the ignition key to ON? Unless the fuel pump turns on and puts gas under high pressure at the fuel injectors, the engine cylinders won't get gas to start. Correct fuel pressure is crucial to know if you have a fuel pump (or fuel filter) problem. If the pressure is correct, it is probably not a fuel problem but a spark problem, although there are less common instances where a fuel injector circuit may malfunction.

The ignition system not producing spark at the spark plugs is the other common problem of no starts. Buy a cheap spark tester at a parts store, plug it into one of your spark plug wires, then crank the engine over and watch for a strong blue spark. You might need a helper to do this. If you see a consistent spark, the ignition system is probably good, although you should probably check more than just one plug wire-sometimes one bad ignition coil in a coil pack will cause no starting. Good luck.

Yes there is a line from the pumt to the injectors....and also a return line. It is unlikey to leak a small amount from this, as any leaks there are under pressure and spill massive amounts...Look around for smaller leaks, often in fuel vapor recovery system...Be sure gas cap is correct one and installed correctly.

I would have someone get on the ground back behind the truck underneath the gas tank and when you turn on the key, you should hear a hum as the fuel pump primes. You could also hook up a fuel pressure gauge on to the schrader valve and see if has the correct pressure or if you get any at all and whether it holds it. If you don't get the correct pressure or it doesn't run at all, then I would say it is the pump. Depending on what fuel system you have you will have different pressures.

I would believe he's correct since when he diagnosed it, he would have hooked up a scanner to your cars computer to retrieve the code that would've caused the check engine light. If the code he retrieves is pointing to your fuel system, then it could be your fuel pump. Odds are the code is saying your system is running to lean which would mean it's not getting enough fuel.

you have a leak in the fuel evaporative emission system. The fuel light flashes when the gas tank and system is not sealed, and the purge control cant **** vacuum or hold vacuum in the tank. Usually its the gas cap not sealing the tank correctly, the "activated charcoal canister shut off valve" wont completely close the system, or the "purge control valve" under the hood isnt opening/pulsing correctly enough for the engine manifold vacuum to create the vacuum in the gas tank