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Help - Fuel Pump


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Hi there, new to the forum.<P>I have a 88 LeSabre and appear to be going on my 4th fuel pump. The original died about 2 years ago. The second two month ago now it looks like the 3rd died yesturday. I am currently in the process of dropping the tank to confirm this but I have any flow up to the filter so it doesn't look good. <P>Anyway, my question is does anybody know why I would be eating pumps? Voltage spikes? Resticted flow (filter is clear)? <P>Thanks in advance,<P>MJL

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I know this can affect the pump since the gas actually acts as coolant for the pump (scary thought), so I try not to let the tank get below 1/4 tank. <P>Thanks

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MJL, hopefully each time the fuel pump was changed the "sock" filter on the pump was also changed. They can plug up with a film from poorly refined gasoline or from some of the junk thaty some companies add. If that sock is plugged, the pump with work itself to death trying to draw the fuel in.

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Make sure you get a GM pump and not an aftermarket. <P>I've heard that they only go out if you try to start the car after its run out of gas.

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A non-restrictive (i.e.,. reasonably fresh) fuel filter is of extreme importance for several reasons. Not only does it let full pressure get to the pressure regulator on the injector rail, it also keeps the pump from drawing too much current (sometimes melting or discoloring the insulation on the wires which supply electricity to the pump on the sending unit itself). Usually, when the filter is restricted, the pump will have a louder whine that should be audible away from the vehicle.<P>Any time the pump is changed, a new fuel pump strainer should be installed--period.<P>Inside the tank, there should be a white plastic baffle that the pump will sit down into. This special plastic keeps fuel around the pump. Make sure that the locating dowels and retainers are tight and that it hasn't broken loose from the inside of the tank. If it's loose in there, but the locating dowels are still there, some appropriate push on retainers need to be replaced. Loose baffles were a problem with the '87 fuel injected Suburbans, which generated the necessary rust resistant flat washers and push on retainers to keep the baffle anchored.<P>Keeping the tank at least 1/4 full is a good orientation. The pump can generate a little heat and the fuel around it does serve as a heat sink, but that heat is less than the flash point of the fuel. The GM pumps are pretty durable at low fuel levels, but they will go away if they run too long with no fuel pumping through them.<P>When a customer comes in with a pretty new car with a fuel pump problem (i.e., died on the road or extended crank time), they will usually admit to running out of gas recently. If they come back again in about 10,000 miles or so with the same issue, it was probably due to a lack of fuel issue again.<P>Always put a new inline fuel filter with a new pump. The failed pump could have put some trash in the lines (which might be partially clogging the old filter).<P>Prior to pulling the tank down, put a meter on the fuel rail and check the fuel pressure. It should come up immediately when the pump is powered up. If, during crank mode, it starts low and builds to the minimum pressure for the engine to run, it's a pump issue. Doing these diagnostics prior to pulling the tank down might be advisable as you'll then know where things are.<P>When those LeSabres were new, there were some fuel pump noise issues that were addressed with a couple of service bulletins. Usually, a "pulsator" or "damper" was put inline on the pump output side just before the pressure line joined the tubing in the sending unit. I don't recall the pulsators ever causing a problem, but at this point in time it could be a possibility. Seems like they were later added in regular production or some other change was made so they weren't needed.<P>My recommendation would be to run the pressure checks and see where things are. Then, put a new fuel filter on an see if things change (pressure or fuel pump noise). You might also backflush the filter to see what might have been in it. Plus, check the voltage at the connector to the fuel tank sending unit to see if it's where it needs to be.<P>For some reasons, the new "reformulated" fuel can clog the inline filters. Therefore, we recommend filter changes at about 30,000 miles (even though there might not be a recommendation in the owner's manual for such).<P>One other word of caution . . . have the tank as near empty as you can before you drop it down from the bottom of the car. Gas weighs about 6 lbs per gallon by itself, not counting the tank and sending unit. It would also be advisable to have the car on a lift with a transmission-style jack to support the tank as you lower it.<P>It might also be possible to access the sending unit/pump by removing an access panel in the floorpan (in the trunk area, under the mat). Some of the later ones are this way and it makes things much easier.<P>Perhaps it would cost more, but I believe that if you have the fuel pump replaced at a Buick or GM dealer, the pump will carry a limited lifetime replacement warranty as long as you own the car. If they install it, I believe it's "parts and labor" but if it's an over the counter sale, it's for parts only. That's the most expensive way to do that deal, but with proper documentation, it should be the last time you have to pay for that repair . . . I'd recommend you check out that option!<P>Plus, if there are some other issues causing the failures (vehicle-related), they'd probably find them too, plus having the diagnostic tools to check the necessary things too.<P>Back then, we had many more problems with the mass air flow sensors than we did with fuel pumps. The car would die out or start running poorly, all of a sudden, but if you tapped on the sensor, it could run fine again. Another reason to have good diagnostics for the problem as you can chunk lots of parts at these newer vehicles and not fix anything.<P>Other things to check for would include the oil pressure sending unit (which tells the ECM to power up the fuel pump when oil pressure is present outside of the crank mode). There might also be a fuel pump relay in the circuit. Have you checked the fuel pump fuse?<P>Thanks for reading through this with me.<P>Just some thoughts . . .<BR>NTX5467<p>[ 06-27-2002: Message edited by: NTX5467 ]

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Guest John Chapman

When we purchased our Camry in 1994, the dealership held classes on the care and feeding of the car. <P>The one item they continuously stressed was fuel pump care. Other than the notes above about keeping 1/4 tank and not operating the pump when out of fuel was the cleanliness of the fuel. The most effective way to trash the fuel system was to get contaminated fuel. The most common way of getting contaminated fuel was to fill up at a station that had just taken a fuel delivery. The flow of fuel into the storage tank stirs up the sediment and it will get pumped right into your tank. If you go to a station and see a tanker truck... find another station. Contaminates precipitate out of gasoline pretty quick, but I'd allow at least two hours post-delivery before pumping fuel from a tank receiving a delivery.<P><BR>Cheers,<BR>JMC

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