2007 Lacrosse fuel pump relay

[Pete O]

What could cause the fuel pump micro relay on my 2007 Lacrosse to be burning out?     It's not like it happens a lot.  I've had the car since new, and I've had to replace it twice now- the first time about 6 years ago, and again just yesterday.  So they last like 6 years .   The casing of the relay is burned brown on the outside,  and luckily the headlight high beam relay is the same as the fuel pump one, so I just switched it to get me home.

 

Thanks

Pete

[NTX5467]

Obviously, the pump is pulling tooo much juice in order to work.  We say something similar on Suburbans (in the wiring on the fuel pump module melting) when the fuel filter hadn't been changed in about 70K miles. The fuel filter restriction made the pump work harder, hence more current through the system.  We advocated the filters be changed every 30K miles, although the maintenance schedule had no recommendations at all.

 

It's not "dirt" that does the clogging.  It's apparently additives in the fuel building up on the filter element and over time, that continued build-up causes the restriction.  A symptom of that is "extended crank time".  Until the fuel injection system gets to about 56psi, the injectors will not fire.  As the engine is cranked, the fuel pressure will rise slowly.  When it touched the magic pressure, the engine suddenly fires and runs.

 

A noisy pump is another symptom, but with the turbine rather than vane pumps, they might not be a noisy as the earlier types.

 

Please advise.

 

NTX5467

[Pete O]

Thanks NTX5467,    I've searched all the online auto parts stores, and none list a fuel filter for a 2007 LaCrosse....

 

 

If searched fuel system schematics, and from what I can see there doesn't seem to be a fuel filter in the system.  I've seen a blog that confirmed this, and mentioned all there is is a screen in the pickup in the fuel tank.

Edited July 6, 2017 by Pete O (see edit history)

[NTX5467]

The fuel pump module "includes non-serviceable lifetime fuel filter".  I found that in ACDelco listing for a fuel pump module at RockAuto.com .  That's where it is and why none listed separately for it.

 

Might need to check the voltage/amp specs on the side of the relay and then do a "current draw" check on the fuel pump circuit.

 

NTX5467

[Beemon]

The pickup screen could also be plugged up, too. I had an issue to this similarly on my 02 Jeep. Pump gas is rated by price depending on their filtration process, I've come to find out. Cheap gas has lots more particulates than expensive gas, and even more so when the station tanks are filled, which can unsettle a lot of the settled dirt. In the end, I had to pull the fuel pump and soak it in solvent like seafoam, or injector cleaner. I also had to spray out the pickup in the tank. Once cleaned and put back together, I haven't had an issue since. This was before I got my Buick running, back when the jeep had its 10 year birthday. Ethanol is really gross when it builds up accumulation. 

[NTX5467]

Only issue is that almost all of the fuel (at least in the metro markets, possibly) come from "fuel terminals", where the particular additives are "splash blended" at the time the fuel goes into the transport tanker.  Not like when the major oil companies owned and operated tank farms in the metro areas, then shipped blended fuel from their own refineries.

 

What CAN be an issue with any fuel station is the result of what's at the bottom of the particular underground tank!  As a Holley engineer once stated, if you see a transport truck at a fuel station, find another station to buy gas from, even if it might mean running out of gas to get there.  Reason?  The fuel going into the tank is a "column of fuel that weights 6lbs/gallon", in motion, with momentum.  When that column of fuel hits the underground tank it naturally will go to the bottom, then blend into the remaining fuel.  This stirs up ALL of the stuff that's settled-out in the bottom of the tank.  The dispensing pumps (on the pump island) are supposed to have filters in them (the size of an FL-1A oil filter) which also react with water, as a water separator filter for a diesel), so there should be enough filtration in there (IF the pumps have these!) to keep water an gunk from reaching a vehicle's fuel tank.  

 

The "grunge" is probably "the gunk" otherwise known as "phase separation" when water/moisture happens and mixes with ethanol in the fuel tank (underground or vehicle).  That stuff also settles to the bottom of the tank (underground or vehicle).

 

In the later 1970s, there was an article on gasoline and its "pow" factor.  The "freshness" of the fuel for racing cars was in the article.  About how to measure the specific gravity of the fuel to determine its freshness and ultimate power factor.  It was mentioned that the better fuels with the highest specific gravity readings would be at the higher-volume stations (which probably would have the newest non-metal tanks).  This, combined with the pump filtration issues, should result in the best product going into the vehicle's fuel tank and the highest specific gravity.

 

Seems like there is a federal spec on the allowable age of underground tanks?  I know there usually has to be some sort of monitoring "well" nearby to detect leaks while they are still small ones, IF they happen.

 

NTX5467