97 Astro Fuel Pump

[astro fan]

I noticed many Astro owners experience fuel pump failures at one time or another. Touch wood, mine has been running for 170,000km!

Has anyone got any idea of the average life expectancy of the fuel pump? Do some run for ever?

I'm considering dropping tank and replacing it along with the sending unit (since this is another popular issue) as preventive maintenance. Winter time I travel long distances with my Astro and I know I would get #!@* at any garage if this would fail away from home.

Thanks in advance

[CD Smalley]

My 92 made it close to 200k before it failed. I really think it's just a matter of time. Also, anytime spent driving on less the 1/4 tank of gas will shorten the life of the pump...

Sounds to me like you have a good idea, given the mileage of your van, to do a pre-emptive strike.

[astro fan]

Thanks CD...

Anybody else has an opinion about this? Please advise.

[rj1721]

I think it might not be a bad idea, but it's pretty expensive. I guess it would be cheaper to do it when your home with time as opposed to on the road. Mine failed on a job site, on a monday, in the winter, just after a big snow, I guess I just expected it to fail when I had time, parked in a safe workable place.

RJ

[pesime]

I have an '89 Astrovan, With 119,000 miles in New York City Traffic, uuuufff!!! has not have a Fuel pump problem yet, but, I never leave the Gas tank less than a quarter and I use gasoline system cleaning aditives once every 3000 miles and change gasoline filter at 7000 miles and Oxigen sensor every 21,000 miles.
Even so, I would like to know how to measure the fuel pump pressure and compare it with the Tune-up specifications.


You can have the best brand new car in the world, but if your car mechanic is bad or wants to destroy it, He will.

[trannyman52]

have replaced several,,,most had plugged filter in the system also,,
sometimes think the plugged filter my put undue stress on the pump
causing the failure !!!! food for thought

[Westone]

Originally Posted by trannyman52

have replaced several,,,most had plugged filter in the system also,,
sometimes think the plugged filter my put undue stress on the pump
causing the failure !!!! food for thought

You are exactly right. To produce a given amount of pressure downstream of the filter, the pump must produce more work upstream of a clogged filter as opposed to a free flowing filter. Regularly changing the fuel filter is key to fuel pump longevity.

I always read that running the fuel level in the tank below a certain point shortens the life of the pump due to a lack of cooling fuel surrounding the pump. This is simply not true. As long as fuel is flowing through the pump when it is running, fuel is in contact with the heat producing movement of the pump, cooling it.

I almost ALWAYS run the tank on our '98 to almost dead empty. (Yesterday I filled it and it was only 3/10s of a gallon shy of empty, about 5 or 6 more miles of driving left in that tank) With 123,000 miles, the pump sounds today the same as it did when new. Listen for changes in the sound of the pump when it is operating. It will often give an indication of an impending failure.

[astro fan]

This is all making sense. A clogged filter will make pump motor work harder therefore explaining the change in sound.

I'm glad you shed some light on the pump cooling 'legend'. I personaly did not believe it since I always empty tank between fill-ups and pump still running after 115,000 miles.

[rj1721]

I was talking a while back to someone and fuel problems came up (non Astro) was with cars in storage for the winter...but maybe...
One of the things he talked about was dirt/rust floating at the bottom of the tank, as the fuel gets low more particle per gallon at the bottom, more junk getting sucked into the screen, more clogged filters.
I never got my brain around the low fuel, pump overheating thing...BUT I can get on board with more junk/rust, more clogged filter, more stress on the filter....change the filter more often.

I bought my truck used and on a long trip, one problem that came up...CLOGGED fuel filter.

RJ

[CD Smalley]

Originally Posted by rj1721

I never got my brain around the low fuel, pump overheating thing...
RJ

It's like the this. The pump uses an electric motor. What will kill electrical products faster than anything? Operating outside their temperature ranges, usually high heat. The fuel in the tank is actually used to keep the pump cool. Running around low on fuel keeps any fuel in the tank from cooling the pump. The pump gets hot and it fails prematurely.

[94&92Astro]

I have three Astro Vans 92 97 and a 94. I have replaced the fuel pump in all of them. The 94 left me far from home in freezing weather without a warning. The other two "sang" loudly and thanks to the 94 I listened. All three vehicles receive lotsa TLC and are in good shape. A mechanic told me people do not normally change the fuel filter as a matter of maintainance and this causes the pump to work harder to push the fuel through--however the driver is oblivious since the van still performs normally. I also understand the years 97 and on are more likely to give warning before going out--(makes a high-pitched singing noise) After you here this don't push it time is near!

Anybody know why fuel pumps made 97 and after cost so darn much as compared to the 96 and earlier models.

[drew300]

My'97: Bought used. I found the fuel filter quite plugged. At 191,000 Kms, i had to change the pump, as the engine became hard to start. (but ran fine once started)
Cooling: The pump assembly I bought, which is the same as came out of the van, has a "well" in which the pump sits. The fuel return line from the engine keeps this well full at all times. And the well doesn't have a drain, so you can run out of fuel, but still have the well full, to cool the pump.
Dirt: the pump inlet is at the bottom of the tank. so it's always getting the fuel off the bottom. The "sock" on the inlet of my old pump was clean when i took it out of the tank.

[94&92Astro]

http://cgi.ebay.com/ebaymotors/NEW-F...QQcmdZViewItem

What the heck is this. Is it an internal part you fit onto your old fuel pump or what'' They sell these on ebay for under $100 and say they will fit 97-99--

[drew300]

They it will work.
It looks like the pump that fits in the assembly. They have white socks for the intake, my GM and replacement were a bronze mesh.
My assembly included the top that plugged the hole in the tank, a new "O" ring, a spring loaded "well" that held the pump, and filter sock (the springs held it the bottom of the tank) and somewhere there was the fuel level sending unit attached in there. The kit aslo included a dielectric grease for the electrical connector, to keep it clean. (there's 10 amps running thru that small connector when the engines' running)
I thought that if I found a pump (like you found), I'd break something trying to replace the pump in the assembly. And I only wanted to do it once.
Good luck

[Blue Bowtie]

Drew is correct. The later systems use a reservoir which contains all the fuel necessary to cool the pump. It is imperative that the pump is allowed to flow fuel to reject heat as well. The FPR should maintain pressure while allowing bypass fuel to return to the tank, keeping fuel moving through the pump even if none is being consumed by the engine.



Another consideration is that while normal heat is not a friend to an electric fuel pump. low pump voltage is a far worse enemy, since it creates further heating (P=IxE) while moving less liquid through the pump to cool it. In addition to this heating, the lower output pressure from low voltage will often cause or contribute to poor starting or no-starts on CPFI systems.

When diagnosing fuel pump problems, pump voltage AT THE PUMP must be checked to verify the integrity of the multitude of connections in the pump circuit. There are three connectors at the pump unit itself, an additional connector in front of/above the tank under the vehicle, another connector at the UEC, the relay and socket, and the B+ connection and bussing. Many good pumps have been condemned as "bad" when only the connections are at fault. A new pump is installed, and barely makes adequate pressure at the reduced voltage, and six months later the vehicle is back in for "another bad pump". I've seen techs replace four pumps on the same vehicle without closely inspecting the connections, thinking each one of the replacements was a "cheapo unit" when in fact the diagnostic skill is what was lacking.

If you have ANY of this at the pump unit in the tank, you need to repair it before proceeding with a new pump:



Those connectors were in a tank unit on an Astro with 70K miles, was running flawlessly, and was only being repaired for a fuel level sensor problem. The pump was supposedly "just fine."