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lm7 startup issue

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Old 07-23-2012 | 11:44 PM
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Default lm7 startup issue

wondering of more likely causes for no start issue i have. Not sure if could be fuel pressure related. There are no codes thrown by the computer yet. O2 sensors are currently missing but it should still run in closed loop.
video:
https://vimeo.com/46266737
Old 07-24-2012 | 12:40 AM
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Mine ran fine with no O2s. That sounds out of time. Did you mess with the timing chain at all? Are the injector wires pinned out correctly?
Old 07-24-2012 | 12:54 AM
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Timing chain was not messed with. I thought it was out of time originally. I have double checked the wiring according to wiring pinout info here:
http://www.lt1swap.com/99-02_vortec_pcm.htm

Everything for coil and injector control matched correctly. I even thought maybe somehow one of the shop towels been left in one of the intake ports but don't want to take it back apart yet.
Old 07-24-2012 | 06:52 PM
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Did you check your fuel pressure at the rails? Should be around 58 psi.
Old 07-24-2012 | 09:46 PM
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I pulled the intake with everything attached to it and checked each injector. One of the injectors did not spray very well, but after cleaning it worked. I have ordered a fitting and a gauge for fuel pressure to check next.
Old 07-26-2012 | 10:07 PM
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checked to fuel pressure and it is good. While trying to start again i noticed that almost all spark plug wires are sparking through cracks. Going to get new spark plug wires and give it another try tomorrow, but it looks like that it is probably what the issue was.
Old 07-27-2012 | 11:13 AM
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if you want to rule out a fuel issue quickly, take your fpr vacuum line off the intake, spray a few shots of ether, carb clean, brake clean we you have laying around flammable and if it cranks up for 10 seconds and shuts down, its a fuel issue, if it still hits and crackles like it does now its an ignition issue.
Old 07-27-2012 | 04:23 PM
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another try today with new spark plug wires and still no start. it fires for a second and then dies. Next step will be to connect oscilloscope to injector control wire to see if it is turning on correctly.
https://vimeo.com/46507289
Old 07-27-2012 | 04:27 PM
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Originally Posted by yevgenievich
another try today with new spark plug wires and still no start. it fires for a second and then dies. Next step will be to connect oscilloscope to injector control wire to see if it is turning on correctly.
https://vimeo.com/46507289
That's acting like VATS isn't turned off in the PCM.
Old 07-27-2012 | 07:33 PM
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after changing platform type to f body engine started. When running a scanner it does not show any value for airflow. Would that indicate that i have a bad maf sensor?
https://vimeo.com/46516754



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