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01-18-2019, 10:22 PM
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#1 |
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Registered User
Join Date: Jul 2014
Location: North-central Virginia
Posts: 1,104
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Can I power up the ECM without an engine attached?
Based on my schematics, the run/crank relay provides an ignition hot source to the ecm. The ecm in turn, activates the powertrain relay, which "turns on" the engine sensors and components. I want to know if the ecm will automatically power up that relay when it gets a key on signal, as does it need a data signal to do so.
If you didn't follow that mumble-jumble, don't sweat it. On to the question... Can I provide 12 volts to the appropriate pins on the ecm, and read the output voltages on various pins without an engine attached? Or is this somehow dangerous or ill advised? I would be doing this through the stock harness and fusebox. So I won't be just blindly pushing alligator clips into the ecm pins... |
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01-19-2019, 12:00 AM
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#2 |
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Registered User
Join Date: Dec 2009
Location: Independence Mo
Posts: 4,118
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Re: Can I power up the ECM without an engine attached?
You can, but not sure why you'd want to?
__________________
My '72 short bed build. http://www.ls1tech.com/forums/conver...6-0-4l80e.html 5.3 swap into my RUSTY '71 C10 http://ls1tech.com/forums/conversion...71-c-10-a.html |
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01-19-2019, 10:32 AM
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#3 |
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Registered User
Join Date: Aug 2006
Location: Redmond, WA
Posts: 6,332
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Re: Can I power up the ECM without an engine attached?
I did. I powered it up and flashed the ECM with a manual trans load before I installed it, because it had been ordered as an AUTO harness. Worked fine.
Get ALL the grounds, and there's no guarantees!
__________________
1970 GMC Sierra Grande Custom Camper - Built, not Bought 1969 Pontiac 2+2 427/390 4-speed Coupe 1969 Pontiac 2+2 427/390 4-speed Convertible |
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