Mechanics

CHEVROLET TRUCK ENGINE PROBLEM

1998 Chevrolet Truck • 11,000 miles

What are symptoms do faulty fuel pump
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Guest
December 27, 2012.




Chrysler pumps typically fail to start up so they leave you stranded in a parking lot or driveway. They almost never fail while they're running. GM pumps typically fail while they are running leaving stranded on the side of the road in the middle of nowhere. Those failures happen more often with high-mileage vehicles and are due to worn brushes inside the pump's motor. All pumps can develop excessive wear between the impeller and housing, or a buildup of debris in the housing. Those can cause lower than acceptable pressure. The symptoms for that varies with the engine size, model year, and brand. Some 50 pound systems like my '88 Grand Caravan will still run with no symptoms when fuel pressure is down to as little as 20 pounds, as I found out last summer. That is not typical. Normally fuel pressure that is low by ten percent can result in a hesitation or stumble on acceleration, or a diagnostic fault code for "engine running too lean". There is one or perhaps a few GM engines that won't even start if the pressure is low by just a few pounds. Sorry I can't tell you which years or models that pertains to but I don't think that is a real common cause of a no-start condition.

You can also listen for the hum of the pump for one or two seconds after turning on the ignition switch. GM pumps usually make plenty of noise in their trucks to be heard easily. Chrysler pumps are built to very tight clearances which makes them very quiet, although you can still hear them. The disadvantage is they are more likely to lock up from microscopic debris in the gas tank, or from a warped housing. The warped housing used to show up in very cold weather, and they'd work fine if you let the truck sit in a heated garage or shop overnight. That problem was solved a long time ago.

Caradiodoc
Dec 28, 2012.


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