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Old 11-24-2020, 05:28 PM   #1
hjs
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Join Date: Feb 2018
Location: Arnoldsville GA
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ecm test question - tbi

there's a 'set timing' connector on the wiring harness for tbi years (i think) 87 to 95. it's a tan/black wire.
if you unplug the connector you bypass the ecm, but the motor will run, and you can set initial timing.
would this also be a good way to test for a faulty ecm? it the motor runs with the tan/black wire unplugged, but does not run with it plugged, wouldn't this point to a bad ecm?
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Old 11-25-2020, 09:22 AM   #2
Katrina/10
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Re: ecm test question - tbi

If you run the engine with the timing connector unplugged, the ECM is still reading sensors, firing fuel injectors, and running the fuel pump. I just isn't controlling the timing anymore.
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Old 11-25-2020, 11:18 AM   #3
hjs
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Re: ecm test question - tbi

oh ok, see that now. thought i was on to something. thanks
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