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  • avatar zaken1 02/18/11 12:26 am PST

    Some normal sparks will not be bright blue. They can vary from blue to orange. If the spark really is weak; it could come from a low battery, or an ignition switch with excessive resistance in it; or bad plug wires. The spark from the coil wire should be able to jump at least a 1/2 inch gap, and ideally be able to jump a gap of 1 inch or more.




    On this vehicle; two different ignition modules were used in 1991. One was only used on fuel injected motors; while the other was only used on carbureted motors. There also were two different types of distributor. If you installed the wrong module or the wrong distributor; that might keep it from starting.




    It also sometimes happens that someone installs a distributor with the rotor pointing to the plug wire for # 1 cylinder; but the crankshaft may be at TDC on the EXHAUST stroke instead of the compression stroke. If that is the case; and you move the plug wires 180 degrees in the cap; so that they will be directly across the center of the cap from where they now are; the firing order will then be right.




    I would recommend testing the compression. I know you said everything is set right; but even the best of us sometimes make mistakes. If the cam timing is really right; the compression should be at least 150 psi. If it is less than 100 psi, the cam timing is probably off.




    The air hose from the mass airflow sensor to the throttle body MUST be connected when you try to start the motor. If it has been connected; briefly disconnect it and spray starting fluid into the throttle body for two full seconds; while the butterfly is held partly open. Then release the butterfly, quickly put the air hose back on, and try to start the motor. If the motor now fires briefly, or starts and then quits; this means that fuel is not getting to the injectors.




    You said you replaced the fuel pump; but can you hear the pump run when the key is turned on; and did you also install a new fuel filter?? A clogged fuel filter or a fuel pump that does not run can prevent the motor from starting.



    Yes; a bad ignition module will shut down the motor.




    I hope this information is helpful.

    Source: 

Answers

  • zaken1 02/18/11 12:26 am PST

    Some normal sparks will not be bright blue. They can vary from blue to orange. If the spark really is weak; it could come from a low battery, or an ignition switch with excessive resistance in it; or bad plug wires. The spark from the coil wire should be able to jump at least a 1/2 inch gap, and ideally be able to jump a gap of 1 inch or more.




    On this vehicle; two different ignition modules were used in 1991. One was only used on fuel injected motors; while the other was only used on carbureted motors. There also were two different types of distributor. If you installed the wrong module or the wrong distributor; that might keep it from starting.




    It also sometimes happens that someone installs a distributor with the rotor pointing to the plug wire for # 1 cylinder; but the crankshaft may be at TDC on the EXHAUST stroke instead of the compression stroke. If that is the case; and you move the plug wires 180 degrees in the cap; so that they will be directly across the center of the cap from where they now are; the firing order will then be right.




    I would recommend testing the compression. I know you said everything is set right; but even the best of us sometimes make mistakes. If the cam timing is really right; the compression should be at least 150 psi. If it is less than 100 psi, the cam timing is probably off.




    The air hose from the mass airflow sensor to the throttle body MUST be connected when you try to start the motor. If it has been connected; briefly disconnect it and spray starting fluid into the throttle body for two full seconds; while the butterfly is held partly open. Then release the butterfly, quickly put the air hose back on, and try to start the motor. If the motor now fires briefly, or starts and then quits; this means that fuel is not getting to the injectors.




    You said you replaced the fuel pump; but can you hear the pump run when the key is turned on; and did you also install a new fuel filter?? A clogged fuel filter or a fuel pump that does not run can prevent the motor from starting.



    Yes; a bad ignition module will shut down the motor.




    I hope this information is helpful.

    Source: 

  • Stever@Edmunds 02/20/11 5:22 pm PST

    You can reply in this thread by clicking the Answer this Question button and that will help keep all the information in one spot. Thanks!

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