I HAVE TO PULL THE FUEL FILTER AND DRAIN THE GAS FROM MY NEW C4, ITS BEEN SITTING FOR 3 YEARS WITH THE SAME GAS, HAD LAST BEEN STARTED A YEAR AGO UNTIL LAST NIGHT. I FIRED IT UP A FEW TIME WITH A SPARING AMOUNT OF ETHER, AND IT STARTED RUNNING, BUT REALLY ROUGH, AND WOULD NOT ACCELRATE, THE GAS SMELLS LIKE OLD FURNITURE POLISH. I ASSUME ILL HAVE TO DRAIN THE FUEL AND REPLACE THE FILTER, ANYONE KNOW WHERE THE FILTER IS AND WHAT THE EASIEST WAY TO DRAIN THE TANK IS? ANY HELP WOULD BE GREATLY APPRECIATED

 

I'm not an expert on the C4 tank. It's not that fun on a C5, I can tell you that.

I'd suggst finding someone who can help you, who knows a bit more, and of course, going it carefully. Drain the tank, flush it (after draining, plug it and put a few fresh galloons of gas in, witha can of something you buy at the Auto Store called Sea Foam. Let it sit a while (several hours or overnight) then drain that, too.

Then, fill it with good fuel, discounnect the fuel line at the engine and turn on the ignition and get the fuel pump to push fuel through the fuel line into a drain cup or something (be very safety careful here, have a extinguisher ready, etc.) and let about a quart run through to clear the old crap out of the fuel line. Replace the filter (and count on replacing it again at about 700 miles).

Now fill the tank with at least several gallons, and another can of Sea Foam, and try to start the car. I expect it will still run lousy, but let the engine chew on the Sea Foam for a while, etc. That stuff often really does work very well at cleaning injectors, etc.

 

The fuel filter on my 86 is located underneath the passenger seat along the chassis, not too far behind the front wheel. You might think about taking that off, then jumping the fuel relay to turn on the fuel pump, and pump all the fuel out. Im not sure if thats the best idea, but it will work.

 

i was able to syphen most of the fuel out via a hose, although it took forever. there fuel was horrid. i added 5 gallons of 93 octane and a whole can of seafoam. i turned her over for a minut to build up fuel in the lines and disconected the fuel filter. i wouldnt have thought the gas wouldve dumped out as fast as it did. i couldnt get the other side of the filter loose and wound up soaked in gas on some nice wet concrete. i abandoned the project for the day and figured that once the fuel stopped leaking id finsh disconnecting the old filter and replace with a new one. i suppose it needed to be flushed anyhow! ill have the car towed home this week from the location where i bought it so that i can tinker in the privacy of my own garage with all my tools and amentities. wish me luck and hopefully with some new fuel she will quit running so rough after while and ill be out cruising. thanks for helping me out, derek

 

Fuel pump will only run fro 2-3 seconds after truning key on if car is not started.

 

You are right, but I think that's only if the fuel line is connected - the pump runs just until it pressurizes the fuel line enough, then stops. At least on my C5, with the line disconnected to flush fuel, the pump will continue running (at least for a while, we never did it more than about 5-10 seconds, that seemed enough).

 

The filter is on the frame rail behind the passengers side front wheel. As for draining the tank. I never tried it. But I wonder if you can get a hose into the tank from the filler neck and syphone it out.. Other wise maybe pull the filter and turn the key on. I would think the fuel pump would run and pump the gas out of the gas line. But be realy careful. Even old gas can be dangerouslly flamable and explosive.

 

Fuel pumps on all GM cars only run 2 - 3 seconds if the ECM does not see an ignition signal. ECM shuts down fuel pump relay. Reasoning is if you are in a wreck, they do not want the fuel pump feading a fire and so forth. Along the same lines as Ford and their inertia switch.

 

thanks for the advice mech however i have two comments.
1. ive already completed this task
2. seeing as how you are an "ASE Master Certified Tech" which i honestly doubt you are, one would think that somewhere during the master certification process you would have realized you can use a jumper wire to the diagnostic port under the dash to run the fuel pump for as long as nesc. if by some twist of fate there not teaching that, i guess ill have to rethink how much stock i put into that "master" certification of the local dealerships, not flaming you, just staing an opinion.

 

Aww, does your mommy know you got at the computer again? Considering your, considerable, knowledge on car repair, I would have sure thought that you could figure out how to diagnose an engine misfire, since any rookie mechanic knows how to do that, or is it that you just like to see your forum posts on the big old screen. "Look what I wrote!"