90 corsica 3.1 no fuel pressure
06-19-2007, 09:04 PM
Fuel pump went out so i changed it. Now when i try to start it it tries to start but wont. When i turn the key to start it the fuel pump comes on for about 3 seconds and shuts off. I took the pump out and tried it on the bench and it runs fine. I got a new fuel pump soloenoid and hooked a volt meter to the fuel pump wires There are 4 solenoid valves on the firewall i dont know fore sure which one is for the fuel pump so i tried the new solenoid on all of them but still get voltage for only 2 to 3 seconds. Is this solenoid located somewhere else? What controls the solenoid? Any help would be appreciated!
06-20-2007, 09:39 AM
GM fuel pumps only kick "on" for 2-3 seconds when starting to build up pressure, then shut off if the engine does not start. So what you describe is normal. The pump should build up 40 lbs+ of pressure so you might check to see if you by chance have that much. Much less and engine won't start. Maybe a plugged fuel filter or maybe another problem all together. Anyway, what you describe is normal for your pump. Get a pressure tester and start from there, then move along to electrical(firing). You do have a relay for your pump on the firewall, but if you hear the pump it is working OK. Common problems for these cars include ignition module, crank sensor, fuel pump, faulty injectors for non start.
06-20-2007, 12:32 PM
So if the fuel line is empty i should blead the air out of the lines and then it should fire ? It makes sense. Thanx
06-20-2007, 01:06 PM
Not sure about bleeding air out.... should build pressure and start without doing that. In fact I do not know a safe way to do that. What I was saying was to go ahead and connect up everything and take a reading on the fuel pressure to see if it is 40lbs. That is what Corsicas have to have. If the pressure is lower than 40 then you might have to replace the fuel filter under the rear axle, or, the new pump may be bad.... The point is that the pump only runs for 2 seconds, which is enough to pump fuel to the injectors. I suppose air could be in the lines but the pressure would still be there in the line until the engine fired up. the pressure should not bleed off for some time so even if there was air in them it would be pretty quickly forced out by the pressure reamaining in the line. If you have 40 lbs pressure and won't start after a few attempts you might have an injector problem or a spark problem.
06-21-2007, 07:32 PM
I put a new fuel filter on also. Now it tries to start but stalls before you can hit the gas. It will start fine using starter fluid in the air intake so the ignition system seems ok. After i try to start it there is no pressure at the test valve but after i turn the key off and back on there is plenty of pressure. The fuel pump runs as you described. Is the pump supposed to kick back on after it starts? It is losing pressure for some reason. I am sure it will run if the pressure would stay up. I also changed the pressure regulator that the fuel line runs in to. Just before the pressure regulator there is a round drum type of thing that the fuel line runs to. Could this be a type of regulator too? Thanx for the help.
07-02-2007, 08:45 PM
Turns out i had bad fuel injectors. Thanks. Car runs great now.Those injectors are very touchy dont try to clean them yourself!
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