Need advice on fuel pump or fuel filter problem

[jvbastro]

Hello, new member here with a new question.
Van: '97 Astro, 170K mi
Symptom: No problem starting the engine, but when driving at any speed and give it hard gas, the engine coughs, sputters a little, then gradually speeds up. At first I thought it was failing to downshift. Mechanic said that trans is downshifting, but fuel pump is failing. Specifically, the fuel pump is putting out enough gas to start the engine but not putting out enough gas under high demand at highway speeds. He suggested replacing the Astro because cost of installing new pump will exceed market value of van.

Current fuel pump does not have that many miles. Fuel pump was replaced once, at 117K miles, by Chevrolet dealer, so I assume they used an AC-Delco pump. Seems like a fuel pump should last longer than 53K miles.

I would like to avoid replacing the van. Discussed symptom with mechanic at Chevy dealer. He said fuel pump failure is a possibility but other possibilities are clogged fuel filter or clogged catalytic converter or bad control module for fuel pump.

Now I am trying to replace fuel filter, but having trouble with very rusty fuel lines and very rusty flare nuts connecting fuel lines to fuel filter. Sprayed lots of penetrating oil on nuts and lines. I am using the correct size flare nut wrench.

I would appreciate any advice about removing flare nuts from the fuel filter without breaking the line.

Does it make sense to continue my attempt to install a new fuel filter? Should I just give up and agree that the fuel pump is at fault and start looking for a replacement vehicle?

[Captn. Crunch]

If you are on a forum it's because you really like your van. It doesn't matter what u drive, sooner or later it's gonna getcha. Would I get rid of my van over a fuel pump? Not a chance. Fuel lines are tough. They're under tha van, exposed to all manner of nasty stuff and don't get touched til something goes wrong. And because its fuel you can't use heat to help. If you have the room, use two hammers and tap on the fittings from either side at the same time. You can cut fuel lines and install new sections with the help of a flairing kit. You are right about the pump. Dealer would have installed ac delco. Good pump. I got 153k outa my original. You should be able to attach a fuel pressure gauge to your fuel rail and drive the van. You can see real time what's happening. A clogged cat usually doesn't cause a stumble. Power loss across the rpm range and notable loss of top end speed. They can be checked with an infrared thermometer. A clogged one will run hot. Don't give up. These things are aggravating but these vans are irreplaceable next your mechanic is gonna make an offer...

[jvbastro]

Thank you for your advice and encouragement. I hope to keep the van for a few more years.

For the past few days, I have been putting penetrating oil on the flare nuts and gas lines, tapping them to cause vibration, and cleaning them with steel wool and emery cloth. I hope to loosen the flare nuts tomorrow, then install a new fuel filter.

[jvbastro]

I was unable to loosen the flare nuts on the gas filter. I guess I could have pulled harder, but I was afraid of breaking the nuts or the gas line.

Today the service department of a Chevy dealer isolated and fixed the problem by removing the gas filter and finding that it was badly plugged. I give them credit for sticking with it until they found the problem and solved it. It was not necessary to replace the fuel pump and therefore not necessary to drop the gas tank. The Astro is running better than it has in a long time.

The fuel lines are still badly rusted, especially the line going from the filter back to the tank. Rusted lines will eventually leak. I do not know any way to replace those gas lines without dropping the tank. So that potential problem remains. But the Astro now seems trustworthy for the road. I think the fuel pump will OK for now.

[ihatemybike]

I've had to replace the hard fuel lines on both my current vans, but only because a line broke while dropping the tank to fix other problems. I've dropped the tank on almost every van I had, it's really not that bad to do.

When your pump goes bad, only replace it with ACDelco/Delphi as others just don't last. Since these vans are getting up there in age, change the fuel and rear brake lines at the same time.