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1990 Chevrolet Lumina Question: My car just keeeps cranking but won't start. What could the cause be?

 

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sieggy023, 3.1L V6, San Lorenzo, CA, February 14, 2012, 15:56
 Rookie

so u think its the pump itself. what about the fuel pressure regulator? i was kinda hesitant on checking that beacause i didnt want to take off the upper intake if i didnt have to

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  • Answer #1

    Hal... (see my shops), February 14, 2012, 16:05
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     Master

    What's the fuel pressure? You need 40-50psi to get it to run. Can you spray carb cleaner into the throttlebody and get the car to start briefly?

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    sieggy023, February 14, 2012, 16:15
     Rookie

    i dont know what the pressure is i dont have a guage to check it. but if i disconnect the fuel line at the filter and run direct power to the pump the pump fills a bucket in no time. and yes if i spray starter fluid or gas into the throttle body it will start briefly

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    Hal..., February 15, 2012, 06:53
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     Master

    You said at the filter. Which side? If its before the filter try after to make sure the filter isn't clogged. If you disconnected the line after the filter it could be the pressure regulator of the fuel injectors are not opening.

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    sieggy023, February 16, 2012, 04:32
     Rookie

    well i changed the fuel pump and the outcome is still no start. Although now there is a bit more pressure at the rail when i push the bleeder valve. I still can get it to start briefly when i spray fuel directly into the throttle body. I even made sure the fuel line and return line werent clogged by disconnecting them in the engine compartment and shooting air through them back towards the tank and just air came out. Im stummped and dont know what to try next. its gotta be the regulator right?

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  • Answer #2

    patrick mannion from Greg Solow's Engine Room, February 14, 2012, 22:59
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     Master

    Remove the fuel hose that goes to the fuel rail and get a friend to crank over the engine to see you have adequate fuel volume (you should have approximately 1 pint of gasoline in ten seconds of cranking). Off course take proper precautions as gasoline is highly flamable. Next "listen" to the fuel injector. Using a mechanic's stethoscope (or use a long screw driver placing the handle end up to your ear place the metal tip end of the screwdriver against the body of the fuel injector), get a friend to crank over the engine while you "listen" to the fuel injector listen to each injector at the same point of the injector body. You should hear "click, click, click" as the injector is electrically opened and closed by the computer. If the injector is not being triggered you will not have fuel getting into the engine's cylinders. Disconnect the electrical connector at the fuel injector with the ignition key in the "on" position, (next position after the accessory position) you should have 12 volts at one of the two wires at the injector. This true for most vehicles but you need to consult a workshop manual for your vehicle to see that this is true for your vehicle. When the engine is running the second wire at the injector gets (triggered) grounded by the computer in your vehicle many times a second controlling exactly when and how much fuel gets injected into the engine. Check for ignition spark. Use caution when checking ignition spark firstly it provides very high voltage (about 15,000 to 40,000 volts) but it is low amperage, it can give an unexpected shock but is unlikely to kill anyone, secondly the spark produced can ignite any flammable gas or liquid (for example gasoline or the gaseous vapors of a lead acid battery). Remove the spark plug wire (or ignition coil if the ignition system on your car is coil over plug type), place an old spark plug with the gap between the electrode and shell of the spark plug "widened" to about .060" or .070" of an inch. Firmly ground the spark plug shell to a good engine ground. Hold the spark plug wire or coil with an insulated pliers and get a friend to crank over the engine while you watch for a pulsing bright spark jumping across the spark plug gap. Look on Youtube for a video on "Check for spark" or Check for ignition spark" I am sure someone has posted a good video clip. There is a company that independent auto repair shops get their information from, this same information is available inexpensively for people that work on their own cars.. The information is year make and model specific, covering repair procedures, torque specifications, fluid capacities and specifications, service bulletins, component locations, wiring diagrams ect.... Alldata is very easy to navigate http://bit.ly/AllData_Repair_Manuals_Online

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    sieggy023, February 16, 2012, 04:39
     Rookie

    you dont think its the fuel pressure regulator? I replaced the pump and still no start. I know i got spark because i can get the car to start briefly by spraying some fuel directly into the throttle body. i guess i'll try testing the injectors like u descibed and see what i come up with.

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