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View Full Version : Fuel pump life expextancy. Also a thank you.


kb8qlg
08-28-2008, 01:15 PM
First of all, thanks for the input on my multi unit alternator replacement. I know a lot more now.
Secondly, my 02 has about 133 thousand miles on her. I wonder just how long the original fuel pump can be expected to last? We travel in the L100 and I'd rather schedule the replacement than do it on the road. I knoe the pump is in the tank, not a fun job.
Another little glitch with this car, when the tank has about 1/4 remaining, and I park on a slight incline it will not start-fuel starved. Anyone else have that problem?

froggy81500
08-28-2008, 01:18 PM
I don't think there is any real way to determine that. The fuel pump in my step-son's 95 explorer just took a dump with 145K miles on the original. I cannot say for sure, but my old chevy truck had over 221K miles on it and I believe that still had the original pump. The previous owner never mentioned replacing it.

L100andSW2
08-29-2008, 05:33 AM
Hey, my '02 2.2 fuel pump failed at 120,000 in March 07. Over 141,000 current miles now. BTW, the '95's fuel pump also gave out at around 120k a few years ago. Only a small sample of two, but it felt like a pattern to me! Just my experience....

s3nfo
08-29-2008, 09:07 AM
Fuel pump life expectancy is very hard to predict. If you never let the tank get real low, the pump stays immersed in fuel and is always cool. If you frequently run with low fuel, the pump can run alot out of the fuel bath and gets hot, shortening it's life expectancy considerably.

tomdkat
08-29-2008, 03:35 PM
The fuel pump on my 2003 LW300 went out on Hwy I-10E, 92mi west of Phoenix, AZ. Yes, I was in the desert! :) I don't recall how many miles I had on the car when it went out but it was less than 100,000.

I didn't know running the car low on fuel caused the fuel pump to run hotter. I'll be more careful about that in the future.

Peace....

froggy81500
08-29-2008, 04:04 PM
Fuel pump life expectancy is very hard to predict. If you never let the tank get real low, the pump stays immersed in fuel and is always cool. If you frequently run with low fuel, the pump can run alot out of the fuel bath and gets hot, shortening it's life expectancy considerably.

I have heard and read, and agree with the cooling effect of fuel on the pump. But I have yet to see anything actually linking the two, constantly running low on gas and short fuel pump life. I would love to see if there truly is a correlation between them.

Sounds like a job for the mythbusters!!!

fdryer
08-29-2008, 06:43 PM
Try this for reasoning about whether or not a fuel pump will burn out if run down to empty. Since no one has burned out a fuel pump, whether individually or from a group gathering to compare notes in a forum as large as this site, there's no proof that running a tank to empty or low would shorten the life of any fuel pump using gasoline as a coolant. Another way to look at this myth would be a very stern warning in every owner's manual against running a tank too low with fuel pump damage as a result. If this were ever true think of the calamity and anger from irate car owners all over the world complaining about burned out fuel pumps and the expense involved to replace each and every one that burns out!? Kind of a ridiculous situation isn't it?

Imagine the following, printed in every car owner's manual;
"WARNING! ! Do not allow your fuel to run below 1/4 or when the LOW FUEL indicator becomes illuminated! To continue driving without stopping to re-fuel will result in fuel pump damage. Please use the warning indicator to re-fuel as soon as feasible. GM/Mercedes-Benz/Volkswagon/Ferrari/Jaguar/Ford/Chrysler/etc. will not warranty nor replace a damaged fuel pump due to driver ignorance of warning indicators alerting to low fuel/fuel pump damage".

Instead we just drive as usual and as soon as the LOW FUEL indicator becomes illuminated most of us use this warning to drive to the nearest gas station and simply fuel up. No major fanfare, no fuel pump burnout, nothing. How many have consistently emptied out their tanks and ran dry along the side of the road? Anyone? And wound up replacing their fuel pump, certain that fuel pump damage resulted from always running the tank dry? Anyone ignorant enough to consistently run a tank dry all the time simply deserves to have their fuel pump burn out. That's just stupidity but in reality this fuel pump won't burn out. Running out of fuel just means no more fuel to pump to the injectors; no fuel means no pressure, no pressure means a dead engine very quickly. A stopped engine also means the fuel pump stopped operating. Attempting to re-start on an empty tank doesn't mean the fuel pump continues to run. Every start means the engine must turn over in order to enable fuel pump operation. No engine rotation, no fuel pump operation so the fuel pump only runs as long as the ignition key is held to the START position. How long before the idiot driver figures out that the tank is empty (the RED low fuel indicator staying on the last 2-3 gallons) and finally gives up when the light goes on (between the ears) that the car won't run on EMPTY? Guess what happens after refilling? The car starts up without complaint. The fuel pump never has a chance to overheat because some feel that the fuel pump runs continuously when the ignition key is in the ON/RUN position. Well most here have found out that this isn't so. When the engine stops the fuel pump stops running. SAFETY.Re-start the engine and the fuel pump resumes running. Allowing the fuel to run down to the LOW FUEL indicator does absolutely no harm since there's at least (2)two gallons at the bottom of the tank. I'm sure there are plenty of drivers that run their tanks to the low fuel level (myself included) without prematurely burning out their pump. Ever. If this were the case, one of the millions driving their car(s) would have spoken up about this a long time ago. Hearsay and rumors are just that if not backed up with visible evidence. And the idiot that does speak up to confirm a premature fuel pump burnout just proves his stupidity in insisting on emptying out his fuel tank every time to prove that fuel pumps do burn out. The low fuel indicator leaving all of us with at least 2-3 gallons of gas still allows a fuel pump to bathe in fuel. Anyone care to prove otherwise? :cool: Time to put this myth to bed.

kb8qlg
09-01-2008, 10:22 PM
I have heard and read, and agree with the cooling effect of fuel on the pump. But I have yet to see anything actually linking the two, constantly running low on gas and short fuel pump life. I would love to see if there truly is a correlation between them.

Sounds like a job for the mythbusters!!!

Thanks for the input. As a matter of curiosity, I've dissected several electric fuel pumps, and the fact is, the fuel that it pumps, flows in and around the electric motor. Thus, the fuel carries away any heat in the motor. The one pump I did have fail, the lead to one of the brushes in the motor was broken.
Maybe other designs do need to remained immersed for cooling, but I have my doubts.

Ex-GMtech
09-02-2008, 12:15 AM
I would like to point out that when the tank was run down, on many older systems, they were not bathed in fuel. As stated, they did have fuel running through them. I personally believe that if you constantly drive around with 1/4 or less and yes, I have seen many people do this, it lowers the life expectancy. How much.......very little. I did drivability work for Oldsmobile and have seen a lot of things both good and bad.
Here is something to think about. The older systems just hung the pump on the sending unit(GM, Ford, some foreign makes). The newer sytems tend to have it inside a container where it is always covered by fuel. Since doing this, I have noticed pumps lasting longer, mileage wise. Not saying they go double or triple the miles, but they do seem to get further.

fdryer
09-02-2008, 08:03 AM
........Secondly, my 02 has about 133 thousand miles on her. I wonder just how long the original fuel pump can be expected to last? We travel in the L100 and I'd rather schedule the replacement than do it on the road. I knoe the pump is in the tank, not a fun job.
Another little glitch with this car, when the tank has about 1/4 remaining, and I park on a slight incline it will not start-fuel starved. Anyone else have that problem?

Was the fuel filter ever replaced at the 100k mile interval or earlier? With that many miles and possible fuel starvation with more than sufficient fuel remaining creating a problem on inclines, it may be worth the time consuming job of replacing the fuel pump not only to dispel any fears of the old pump dying but maybe to find out if there's crud, water, or what-have-you on the bottom of the tank preventing starts on inclines. The two issues may be good enough for you to kill two birds with one stone. I have a short steep driveway and the times I let my tank run down only to turn on the LOW FUEL light the next morning I've never given thought to fuel starvation. I would guess that the 2-3 gallons remaining is sufficient to keep the pump from burping. Call it dumb luck or whatever. Replacing the filter, pump, and dumping out the remaining fuel should tell you a lot. If you decide on the pump replacement either run the tank down to the lowest level and/or pump out the fuel before the filter (if its near the tank) into a five gallon gas can. One way to run the pump would be to set up the fuel hose into the gas can safely and then temporarily wire a jumper between socket pins 30 and 87 of the fuel pump relay; ignition doesn't have to be on for this and the fuel pump will run continuously unless you remove the wire jumper when the tank is empty. Have two people for this, one to monitor the fuel pumping out into the gas container and you standing by the relay circuit to disable pumping as its dangerous with a constantly running pump.

kb8qlg
09-12-2008, 03:56 PM
Was the fuel filter ever replaced at the 100k mile interval or earlier?
Yes, the filter was replaced at about 100K. Your other points are well taken, will look into new pump ans associated items. Thank you.

td1238
12-12-2011, 10:29 PM
This is a VERY old thread, but I wanted to add to it because I saw some things that interested me. First, I have a '99 SL2 that currently has over 227,000 miles on the ODO. I suspect that there is an ever so slight possibility that the fuel pump is trying to die (brushes are wearing out), because it was very difficult to start this morning, and otherwise normally starts very easily, and just about every other control/supply/ignition device on the car is brand new. When starting this morning, symptoms were somewhat indicative of fuel starvation. ...But the car now runs fine.

I agree with fdryer regarding running the tank low and not damaging the fuel pump. The fuel runs through and around the pump, and keeps it cool, and since some is always returning to the tank through the regulator, the pump always has a constant supply of cooling fluid. It is more likely that the brushes would wear out.

I also always run my tank empty, typically until the low fuel light comes on. I have always done this. My friend always runs his 1990 Honda Civic empty. It currently has 262,000 miles on the ODO, and he's owned it since it had about 89,000 miles. The fuel pump is original. Many other friends I know also run the tank low consistently, and don't complain of fuel pump failures. Filter restriction could reduce effective cooling, though my friend didn't change his Civic's original fuel filter until 200,000 miles. It was quite blocked up. Although a new filter did make a notable change in engine operation, the fuel pump did not fail.

Regarding not being able to start the car on an incline at a quarter tank or less, my car does not do this, but has a similar problem: it cuts out on hard right turns at a quarter tank or less. The problem gets progressively worse as the tank is emptied more. Eventually it gets to the point that the engine will try to stall on moderate to hard stops on a decline, but it typically catches and resumes operation once the car comes to a complete stop. This and the original poster's problem are likely due to a shifted pick-up tube, so that the pump is not drawing fuel from the lowest and most ideal point in the tank.