Lmm randomly stopped building rail and won’t start

Dante2795

Member
Aug 19, 2017
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My lmm has been perfectly fine until I noticed an injector leak. So I fixed it and unplugged fpr to check for more leaks. Well it maxed rail out then stalled and it will not start back up. It won’t build any rail pressure at all to start. I loosed HP line from pump while cranking and plenty of fuel shoots out. I’ve tried starting with FPR unplugged and nothing as well. Also unplugged rail pressure sensor to make that maxes out and it does.

truck has 100s and Exergy 12mm pump
 

gmduramax

Shits broke
Jun 12, 2008
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I don’t think you’re supposed to unplug the FPR when you have a race plug. That would make a shit ton of pressure
 

2004LB7

Well-known member
Dec 15, 2010
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What kind of return do you have on the injectors and CP3. Almost think something broke when you maxed it out and now its all dumping down the return
 

Dante2795

Member
Aug 19, 2017
64
1
8
What kind of return do you have on the injectors and CP3. Almost think something broke when you maxed it out and now its all dumping down the return


Passenger side injectors didn’t return any fuel while cranking
Driver side however was shooting a good bit out. tomorrow I will actually do each injector on that side and see results

I guess maybe the spike ruined something or all injectors on driver bank
 

2004LB7

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Dec 15, 2010
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Be careful with that injector. Make sure it didn't crack the nozzle, body or some other part. Would suck to put it all back together only to have it crack a piston from leaking fuel into the cylinder. Maybe you could install it pointing up/rotated so that you can watch for any leaks