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Slow Start and starter hangs

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Old Apr 2, 2024 | 01:37 PM
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Default Slow Start and starter hangs

So alot going on here

Just built/installed a new engine in my '64 Nova. Engine is an LQ9 w/799 heads (about 11:1) and a decent cam. The car has the battery in the trunk (NHRA cutoff, gigantic gauge wire, amazing grounds) as well as a starter selnoid back there too. The starter is a newish (1 year old) ACDelco and since I have a starter noid in the trunk I Jumped the starter post to the noid post on the starter... pretty typical setup. I use a dished flexplate and a long snout 9.5" 3400 converter and a 4L80e, no alignment issues, everything went together nicely.

Just got to the point of starting her in the car and the starter sounds like it's hanging up in the flexplate... AND the car comes to life real slowly... Like the RPMs remain real low for a bit before it gets to the idle RMP.. To the point where I'm seeing a decent hit count on my scanner logs in the 400 RPM area..

I did have 2 starter shims installed so I took them out and that didn't change a thing. If your wondering why I had 2 shims its because when I started her on the stand I had an annoying tweet/screetch when starting. The starter did not hangup when starting on the stand, it also didn't have a tranny bolted to it so there is that.

My questions?

Just getting back to HPT (from Holley) to improve the initial startup so that she comes to life a bit quicker, can I just add a bit of idle air? Also wondering if this might help the starter release?
Anyone know what causes the tweet/screetch when the starter engauges the flexplate, it's an SFI FP. I thought it was the starter being too tight hence the shims but that didn't seem to work.
Would a weak battery cause a starter to hangup, I have a optima battery but I'm starting to wonder if it's failing under load.
Would the jumper wire on the starter be a problem, this is the first time I've done this config for a LS. The trigger wire for the starter noid comes right off the key as it should.
Anything I'm missing that I should have asked/provided?


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Old Apr 2, 2024 | 02:16 PM
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Just found startup airflow...thats feels like a better place to start with my lazy startup.
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Old Apr 2, 2024 | 07:25 PM
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Okay so 15% to start air initial gets her to fire much better!

the starter still hangs…

also changed the battery out and it still hangs..

next test

- swap starter , with and without the jumper

also when I started it on the stand there was no jumper so I’ll test it that way first.

-
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Old Apr 2, 2024 | 07:37 PM
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Okay so 15% to start air initial gets her to fire much better!

the starter still hangs…

also changed the battery out and it still hangs..

next test

- swap starter , with and without the jumper

also when I started it on the stand there was no jumper so I’ll test it that way first.

-
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Old Apr 11, 2024 | 08:08 PM
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So to close this out…

I pulled the tranny back and replaced the FW and Starter. Spins over nicely now!

FW was cracked and starter I think is smoked as a result.

the starter still hangs up a bit but I have another thread going and my remote starter mood wiring might be the problem…
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