Expert: Rob Painter - 3/25/2011

Question
I have just replaced a fuel pump in my 1993 caddilac fleetwood the first one I bought showed only 10 pounds of pressure so I took it bac n got another one n it also showed rhe same amount but now the pump doesnt kick on at all what could that be

Answer
Hello,

Obviously without being at the vehicle, there is no way for me or anyone on the web to give you the answer you are looking for because components have been changed and altered from it's original state.

You did not state as to why you changed the fuel pump in the first place. Was the engine hesitating? Lack of power? What was the initial problem.

I have seen people go to all the work of changing a fuel pump only to find that it was a problem like a plugged catalytic converter.

At least you ruled that out by checking the fuel pressure, but in the fuel delivery system, often over looked in a pressure situation is the fuel filter. If the filter is plugged, it will definitely affect pressure.

Now you state since you replaced the pump, you don't have the fuel pump kick on. You could have blown the fuel pump fuse. You could have a connection issue at the pump and yes, you could have a faulty fuel pump.

With the ignition on, you need to check to see if there is power going to the fuel pump at the tank. If there is power going to the fuel pump, you have a bad pump unit. If not, you need to find out why.

If this was a drive ability problem the question I would have would be; was the original pump showing the same 10 pounds pressure as the pump you returned? If so, the fuel pump was not even the original problem and I would be seriously consider replacing the fuel filter. Even as a maintenance issue, the filter should have been replaced when dealing with a fuel delivery issue on a 18 year old car.


You by far are not the only one who has gone for the fuel pump first on a fuel delivery problem because it is the first thing thought of. Am I an expert on fuel delivery issues? I know more than many, however it is not my specific expertise. however, I have dealt with these issues on more than one occasion and have had a tendency of being correct.

I hope my information helps you in the diagnoses as to determine why the fuel pump is not running and I hope that the only problem past the fuel pump is as simple as a plugged fuel filter.

I also recommend that when people are trying to work on their cars that they have the right equipment. What I do with a problem car is seek out the factory service manual with diagnostic flow charts which prevents changing good parts with a guess. I pay the $30 and download all this information for a year and if you have a second car, you can do that for $15. I go to http://www.alldata.com scroll for the exact car and download. $30 is a very low cost compared to all the time effort and cost of potential replacement components that did not need to be changed.

Good luck!


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