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ECU affecting starter?

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Old Apr 27, 2024 | 04:21 PM
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Default ECU affecting starter?

Can ECU issues have any effect on starter operation? Odd question I know, but there is reason. Doing some troubleshooting / diagnostics and this may (or may not) be useful information in that process. Car is a '94.
Same question will be posted in the LS forum as well - the way I see it it's all 1UZ and I want to cast a wide net.
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Old Apr 28, 2024 | 07:37 AM
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No interaction that I'm aware of, for what little that's worth.
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Old Apr 28, 2024 | 05:21 PM
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Originally Posted by t2d2
No interaction that I'm aware of, for what little that's worth.
Kind of what I thought, but I'm starting to wonder.
Could it be a totally parallel system?
Or is it the computer that energizes the relays (via the ignition switch) etc to make things happen?
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Old Apr 28, 2024 | 11:20 PM
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What issues are you having? Low idle? obviously it's a no start assuming by the title.
Usually is key to starter relay to starter. The ECU will get a signal, but as long as the triangle are getting power then it should start. If you have an immobilizer, then it would be an intercepting signal from a secondary source, which in this case would be the alarm brain box to the code on the key to the ECU. Oversimplified in a way, if I'm wrong feel free to correct me.
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Old Apr 29, 2024 | 10:58 AM
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Originally Posted by Tallyhoe
What issues are you having? Low idle? obviously it's a no start assuming by the title.
No, it's actually not a no start issue. it's a "sometimes" start issue. "start only with foot on gas" issue among other things (unstable idle, just plain stalling out).

The main concern with this post is a crank / starter not fully disengaging or slowly disengaging the flexplate.
I would just assume it's a starter only thing ... except this behaviour is one of a few things that are happening all at once.

When I see a bunch of crazy stuff happening all at the same time (when it was fine the day before). makes me think ECU.
So point of this particular thread is really only one part of my diagnostic path.

All input is appreciated!


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Old Apr 30, 2024 | 08:03 AM
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I suppose you could disconnect the ECU and see if the starter relay is still energized.
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Old May 2, 2024 | 05:45 PM
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Originally Posted by t2d2
I suppose you could disconnect the ECU and see if the starter relay is still energized.
Good point. Of course now that particular problem has (temporarily) "fixed" itself
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